wave12: 501/237 — ClickHouse/Druid/Pinot + Ansible/OpenTofu/Pulumi + Celery/Camel + VictoriaMetrics/Ceph

This commit is contained in:
russell@unturf.com 2026-03-27 17:34:59 -04:00
parent 19333b378e
commit 424a2a7787
31 changed files with 2994 additions and 5 deletions

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# ansible-0001: Role.get_vars() seen-list O(D²) deduplication
## Classification
- **Severity**: MEDIUM
- **CWE**: CWE-407 (Algorithmic Complexity — Inefficient Algorithmic Complexity)
- **Component**: `lib/ansible/playbook/role/__init__.py`
## Location
`lib/ansible/playbook/role/__init__.py`, method `get_vars()`, lines 539546
```python
seen = []
for dep in self.get_all_dependencies():
# Avoid rerunning dupe deps since they can have vars from previous invocations
if dep not in seen:
all_vars = combine_vars(all_vars, dep.get_vars(include_params=False, only_exports=True))
seen.append(dep)
```
## Pattern
`seen` is initialized as a Python `list`. The membership test `dep not in seen` is O(D) for each of D dependencies → total O(D²). In a large Ansible playbook with deeply nested roles (e.g. enterprise roles with D=100+ transitive dependencies), this produces D(D-1)/2 comparisons.
## Speedup
At D=200 dependencies: 19,900 comparisons → 200 comparisons (99.5x reduction)
## Patch
```diff
--- a/lib/ansible/playbook/role/__init__.py
+++ b/lib/ansible/playbook/role/__init__.py
@@ -536,10 +536,10 @@ class Role(Base, Become, Conditional, Taggable, CollectionSearch):
# get exported variables from meta/dependencies
- seen = []
+ seen = set()
for dep in self.get_all_dependencies():
# Avoid rerunning dupe deps since they can have vars from previous invocations and they accumulate in deps
# TODO: re-examine dep loading to see if we are somehow improperly adding the same dep too many times
if dep not in seen:
# only take 'exportable' vars from deps
all_vars = combine_vars(all_vars, dep.get_vars(include_params=False, only_exports=True))
- seen.append(dep)
+ seen.add(dep)
```
Note: `Role` objects are used as set members; Python uses identity (`id()`) by default for unhashed objects, which is correct here — same object in memory = same dep. If Role doesn't define `__hash__`, Python uses the default identity hash.
## Complexity
- Before: O(D²) — D = number of transitive role dependencies
- After: O(D) — set membership is O(1) amortized

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package unit;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
/**
* ansible-0001: Role.get_vars() seen-list O(D²) deduplication
*
* Slow: uses List for seen-set dep not in seen is O(D) per iteration O(D²) total
* Fast: uses HashSet for seen-set dep not in seen is O(1) per iteration O(D) total
*
* Verifies: slow_ops >= D*(D-1)/2, fast_ops == D, ratio >= 10x at D=200
*/
public class AnsibleRoleGetVarsAlgorithm {
static long slowOps = 0;
static long fastOps = 0;
/** Simulated Role dependency — identity-based equality (no custom equals/hashCode) */
static class MockDep {
final int id;
MockDep(int id) { this.id = id; }
}
/**
* Slow version: seen is an ArrayList contains() is O(D)
* Mirrors: seen = []; if dep not in seen: seen.append(dep)
*/
static int slowGetVars(List<MockDep> allDependencies) {
slowOps = 0;
List<MockDep> seen = new ArrayList<>();
int combinedCount = 0;
for (MockDep dep : allDependencies) {
// Each call to contains() scans the entire seen list O(seen.size())
for (MockDep s : seen) {
slowOps++;
if (s == dep) break; // found
}
// Equivalent of: if dep not in seen
boolean inSeen = false;
for (MockDep s : seen) {
if (s == dep) { inSeen = true; break; }
}
if (!inSeen) {
// combine_vars equivalent
combinedCount++;
seen.add(dep);
}
}
return combinedCount;
}
/**
* Fast version: seen is a HashSet contains() is O(1)
* Mirrors: seen = set(); if dep not in seen: seen.add(dep)
*/
static int fastGetVars(List<MockDep> allDependencies) {
fastOps = 0;
Set<MockDep> seen = new HashSet<>();
int combinedCount = 0;
for (MockDep dep : allDependencies) {
fastOps++;
if (!seen.contains(dep)) {
combinedCount++;
seen.add(dep);
}
}
return combinedCount;
}
/**
* Build a dependency list with D unique deps, no duplicates (worst case for seen growth).
*/
static List<MockDep> buildDeps(int D) {
List<MockDep> deps = new ArrayList<>();
for (int i = 0; i < D; i++) {
deps.add(new MockDep(i));
}
return deps;
}
public static void main(String[] args) {
int passed = 0;
int total = 0;
// Test 1: basic correctness both produce same combined count
{
total++;
int D = 10;
List<MockDep> deps = buildDeps(D);
int slowResult = slowGetVars(deps);
int fastResult = fastGetVars(deps);
boolean ok = (slowResult == D && fastResult == D);
System.out.println((ok ? "PASS" : "FAIL") + " [correctness D=" + D + "]: slow=" + slowResult + " fast=" + fastResult);
if (ok) passed++;
}
// Test 2: with duplicates both should deduplicate identically
{
total++;
int D = 5;
List<MockDep> unique = buildDeps(D);
List<MockDep> depsWithDups = new ArrayList<>();
for (MockDep dep : unique) { depsWithDups.add(dep); depsWithDups.add(dep); } // each dep appears twice
int slowResult = slowGetVars(depsWithDups);
int fastResult = fastGetVars(depsWithDups);
boolean ok = (slowResult == D && fastResult == D);
System.out.println((ok ? "PASS" : "FAIL") + " [dedup D=" + D + " with dupes]: slow=" + slowResult + " fast=" + fastResult);
if (ok) passed++;
}
// Test 3: slow op count is O(D²) at least D*(D-1)/2 comparisons
{
total++;
int D = 200;
List<MockDep> deps = buildDeps(D);
slowGetVars(deps);
long minExpectedSlowOps = (long) D * (D - 1) / 2;
boolean ok = slowOps >= minExpectedSlowOps;
System.out.println((ok ? "PASS" : "FAIL") + " [slow O(D²) D=" + D + "]: ops=" + slowOps + " >= " + minExpectedSlowOps);
if (ok) passed++;
}
// Test 4: fast op count is exactly O(D) one check per dep
{
total++;
int D = 200;
List<MockDep> deps = buildDeps(D);
fastGetVars(deps);
boolean ok = (fastOps == D);
System.out.println((ok ? "PASS" : "FAIL") + " [fast O(D) D=" + D + "]: ops=" + fastOps + " == " + D);
if (ok) passed++;
}
// Test 5: ratio >= 10x at D=200
{
total++;
int D = 200;
List<MockDep> deps = buildDeps(D);
slowGetVars(deps);
long slowCount = slowOps;
fastGetVars(deps);
long fastCount = fastOps;
double ratio = (double) slowCount / fastCount;
boolean ok = ratio >= 10.0;
System.out.printf((ok ? "PASS" : "FAIL") + " [ratio D=%d]: slowOps=%d fastOps=%d ratio=%.1fx%n", D, slowCount, fastCount, ratio);
if (ok) passed++;
}
System.out.println(passed + "/" + total + " PASS");
if (passed != total) System.exit(1);
}
}

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# camel-0001 — O(R²) Route Startup Endpoint Clash Scan
**Severity:** HIGH
**Complexity:** O(R²) → O(R)
**CWE:** CWE-407 (Algorithmic Complexity)
## Affected File
| File | Lines | Notes |
|------|-------|-------|
| `core/camel-base-engine/src/main/java/org/apache/camel/impl/engine/InternalRouteStartupManager.java` | 357444 | Route startup consumer clash check |
## Defective Code
### `InternalRouteStartupManager.doStartOrResumeRouteConsumers` lines 357444
```java
List<Endpoint> routeInputs = new ArrayList<>();
for (Map.Entry<Integer, DefaultRouteStartupOrder> entry : inputs.entrySet()) {
// ...
Endpoint endpoint = consumer.getEndpoint();
// CHECK 1: O(R) linear scan inside O(R) outer loop → O(R²)
if (!doCheckMultipleConsumerSupportClash(endpoint, routeInputs)) {
throw new FailedToStartRouteException(...);
}
// CHECK 2: rebuild existingEndpoints as ArrayList each iteration → O(R²)
List<Endpoint> existingEndpoints = new ArrayList<>();
for (Route existingRoute : camelContext.getRoutes()) {
// ... add to existingEndpoints
}
if (!doCheckMultipleConsumerSupportClash(endpoint, existingEndpoints)) {
throw new FailedToStartRouteException(...);
}
routeInputs.add(endpoint); // List grows by 1 each iteration
}
```
`doCheckMultipleConsumerSupportClash` calls `routeInputs.contains(endpoint)` and
`existingEndpoints.contains(endpoint)`. Both lists use `ArrayList.contains()` which
is O(N). The outer loop runs R times (R = number of routes). Total: O(R²).
## Root Cause
`routeInputs` is declared as `ArrayList<Endpoint>`. The `.contains()` call scans
every existing element linearly. At R=1000 routes, this is ~500,000 comparisons
instead of ~1,000.
## Fix
Replace `ArrayList<Endpoint>` with `LinkedHashSet<Endpoint>` (preserves insertion
order, provides O(1) `contains()`):
```java
// Before
List<Endpoint> routeInputs = new ArrayList<>();
// After
Set<Endpoint> routeInputs = new LinkedHashSet<>();
```
`doCheckMultipleConsumerSupportClash` accepts a `Collection<Endpoint>` parameter
(declared as `List<Endpoint>`), so the call site parameter type must also be updated:
```java
// Before
private boolean doCheckMultipleConsumerSupportClash(Endpoint endpoint, List<Endpoint> routeInputs)
// After
private boolean doCheckMultipleConsumerSupportClash(Endpoint endpoint, Collection<Endpoint> routeInputs)
```
For `existingEndpoints`, use `LinkedHashSet` as well:
```java
// Before
List<Endpoint> existingEndpoints = new ArrayList<>();
// After
Set<Endpoint> existingEndpoints = new LinkedHashSet<>();
```
## Impact
- Affects Camel applications with R ≥ 50 routes at startup
- Startup time grows quadratically with route count
- At R=500: ~12,500 comparisons → ~500 (25x reduction)
- At R=1000: ~500,000 comparisons → ~1,000 (500x reduction)
- Cloud deployments with large route counts (e.g., microservice monorepos using Camel) are most affected

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package unit;
import java.util.ArrayList;
import java.util.Collection;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;
/**
* camel-0001: InternalRouteStartupManager.doStartOrResumeRouteConsumers
*
* Defect: routeInputs is ArrayList<Endpoint>. Each iteration calls
* routeInputs.contains(endpoint) O(R) inside an O(R) outer loop = O(R²).
*
* Fix: use LinkedHashSet<Endpoint> for O(1) contains().
*/
public class RouteStartupAlgorithm {
// --- Slow path: ArrayList.contains() in loop ---
static long slowStartupCheck(int routeCount) {
long ops = 0;
List<String> routeInputs = new ArrayList<>();
for (int i = 0; i < routeCount; i++) {
String endpoint = "endpoint-" + i;
// Simulate: if (!doCheckMultipleConsumerSupportClash(endpoint, routeInputs))
// doCheckMultipleConsumerSupportClash calls routeInputs.contains(endpoint)
ops++;
boolean clash = routeInputs.contains(endpoint); // O(i) scan
if (clash) {
throw new RuntimeException("unexpected clash at " + i);
}
// Simulate existingEndpoints rebuild each iteration
List<String> existingEndpoints = new ArrayList<>();
for (int j = 0; j < i; j++) {
existingEndpoints.add("endpoint-" + j);
ops++;
}
// contains check on existingEndpoints
ops++;
boolean existingClash = existingEndpoints.contains(endpoint); // O(i) scan
if (existingClash) {
throw new RuntimeException("unexpected existing clash at " + i);
}
routeInputs.add(endpoint);
}
return ops;
}
// --- Fast path: LinkedHashSet.contains() in loop ---
static long fastStartupCheck(int routeCount) {
long ops = 0;
Set<String> routeInputs = new LinkedHashSet<>();
Set<String> existingEndpointsSet = new LinkedHashSet<>();
for (int i = 0; i < routeCount; i++) {
String endpoint = "endpoint-" + i;
// O(1) contains
ops++;
boolean clash = routeInputs.contains(endpoint);
if (clash) {
throw new RuntimeException("unexpected clash at " + i);
}
// No need to rebuild existingEndpoints; maintain incrementally
ops++;
boolean existingClash = existingEndpointsSet.contains(endpoint);
if (existingClash) {
throw new RuntimeException("unexpected existing clash at " + i);
}
routeInputs.add(endpoint);
existingEndpointsSet.add(endpoint);
}
return ops;
}
static void runTest(String label, int N, long slowOps, long fastOps) {
double ratio = (double) slowOps / fastOps;
boolean pass = ratio >= 10.0;
System.out.printf(" %-12s N=%-5d slow=%,7d fast=%,5d ratio=%5.1fx %s%n",
label, N, slowOps, fastOps, ratio, pass ? "PASS" : "FAIL");
if (!pass) {
throw new AssertionError("Ratio " + ratio + " < 10x threshold at N=" + N);
}
}
public static void main(String[] args) {
System.out.println("camel-0001: RouteStartupAlgorithm");
System.out.println(" Defect: ArrayList.contains() in O(R) loop → O(R²)");
System.out.println(" Fix: LinkedHashSet.contains() → O(R)");
System.out.println();
int[] sizes = {100, 300, 500};
int passed = 0;
int total = sizes.length;
for (int N : sizes) {
long slowOps = slowStartupCheck(N);
long fastOps = fastStartupCheck(N);
try {
runTest("route-startup", N, slowOps, fastOps);
passed++;
} catch (AssertionError e) {
System.out.println(" FAIL: " + e.getMessage());
}
}
System.out.println();
System.out.println(passed + "/" + total + " PASS");
if (passed < total) {
System.exit(1);
}
}
}

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# celery-0001 — O(N²) ResultSet Membership Test in update()/add()
**Severity:** MEDIUM
**Complexity:** O(N²) → O(N)
**CWE:** CWE-407 (Algorithmic Complexity)
## Affected File
| File | Lines | Notes |
|------|-------|-------|
| `celery/result.py` | 597598, 629631 | ResultSet.add() and ResultSet.update() |
## Defective Code
### `celery/result.py` line 597598 — `ResultSet.add()`
```python
def add(self, result):
if result not in self.results: # O(N) list scan
self.results.append(result)
```
### `celery/result.py` line 629631 — `ResultSet.update()`
```python
def update(self, results):
"""Extend from iterable of results."""
self.results.extend(r for r in results if r not in self.results)
# ^^^^^^^^^^^^^^^^^^^
# O(N) scan per element → O(M*N)
```
`self.results` is a plain `list` (see line 586: `self.results = results`).
Each `r not in self.results` scan is O(N). When `update()` merges M new results
into a set of N existing results the total cost is O(M×N). For chord groups with
thousands of tasks this becomes the bottleneck.
## Root Cause
`ResultSet.results` stores `AsyncResult` objects in a `list`. Deduplication uses
linear scan (`not in list`) instead of a `set`/`dict` lookup.
## Fix
Maintain a parallel `set` for O(1) membership:
```python
def __init__(self, results, app=None, ready_barrier=None, **kwargs):
self._app = app
self.results = results
self._result_ids = {r.id for r in results} # shadow set for O(1) lookup
...
def add(self, result):
if result.id not in self._result_ids:
self._result_ids.add(result.id)
self.results.append(result)
if self._on_full:
self._on_full.add(result)
def update(self, results):
for r in results:
if r.id not in self._result_ids:
self._result_ids.add(r.id)
self.results.append(r)
```
Alternatively, change `results` to an `OrderedDict` keyed by `result.id`.
## Impact
- Affects `group()` / `chord()` workflows with large task counts
- `update()` is O(M×N) → becomes the dominant cost for chord result collection
- At N=M=1000: 1,000,000 comparisons vs 1,000 dict lookups (1000x overhead)
- Backend chord unlock (`celery.chord_unlock`) iterates `header_result.results`
which triggers the O(N²) path when merging partial completions

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package unit;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
/**
* celery-0001: ResultSet.update() / ResultSet.add()
*
* Defect: self.results is a plain list. The expression
* 'r not in self.results' (Python)
* becomes an O(N) scan on each of M elements in update() O(M*N) total.
*
* Fix: maintain a parallel dict keyed by result ID for O(1) membership.
*
* Op counting: each comparison during the list scan counts as one op.
* For hash lookup we count 1 op per lookup.
*/
public class ResultSetAlgorithm {
// --- Slow path: simulate list.contains() with explicit scan counting ---
static long slowUpdate(int existingCount, int newCount) {
long ops = 0;
List<String> results = new ArrayList<>();
for (int i = 0; i < existingCount; i++) {
results.add("result-" + i);
}
// simulate: self.results.extend(r for r in results if r not in self.results)
for (int i = existingCount; i < existingCount + newCount; i++) {
String r = "result-" + i;
// Scan the list: worst case is a full pass (item not found)
for (String existing : results) {
ops++; // each comparison costs 1 op
if (existing.equals(r)) break;
}
// Item not in list, add it
results.add(r);
}
return ops;
}
// --- Fast path: LinkedHashMap (idresult) simulation ---
static long fastUpdate(int existingCount, int newCount) {
long ops = 0;
Map<String, String> resultMap = new LinkedHashMap<>();
for (int i = 0; i < existingCount; i++) {
String r = "result-" + i;
resultMap.put(r, r);
}
for (int i = existingCount; i < existingCount + newCount; i++) {
String r = "result-" + i;
ops++; // O(1) hash lookup counted as 1 op
if (!resultMap.containsKey(r)) {
resultMap.put(r, r);
}
}
return ops;
}
// --- Slow path: add() pattern ---
// Simulates: if result not in self.results: self.results.append(result)
// Called N times for sequential task completions in a chord group.
static long slowAdd(int N) {
long ops = 0;
List<String> results = new ArrayList<>();
for (int i = 0; i < N; i++) {
String r = "result-" + i;
// Scan entire list for membership check
for (String existing : results) {
ops++;
if (existing.equals(r)) break;
}
// Not found append (all N items are unique, so full scan each time)
results.add(r);
}
return ops;
}
// --- Fast path: add() pattern ---
static long fastAdd(int N) {
long ops = 0;
Map<String, String> resultMap = new LinkedHashMap<>();
for (int i = 0; i < N; i++) {
String r = "result-" + i;
ops++; // O(1) lookup
resultMap.putIfAbsent(r, r);
}
return ops;
}
static void runTest(String label, int N, long slowOps, long fastOps) {
double ratio = (double) slowOps / fastOps;
boolean pass = ratio >= 10.0;
System.out.printf(" %-14s N=%-5d slow=%,8d fast=%,5d ratio=%6.1fx %s%n",
label, N, slowOps, fastOps, ratio, pass ? "PASS" : "FAIL");
if (!pass) {
throw new AssertionError("Ratio " + ratio + " < 10x threshold at N=" + N);
}
}
public static void main(String[] args) {
System.out.println("celery-0001: ResultSetAlgorithm");
System.out.println(" Defect: list.contains() per element in update()/add() → O(N²)");
System.out.println(" Fix: dict/map key lookup → O(N)");
System.out.println();
int[] sizes = {200, 500, 1000};
int passed = 0;
int total = sizes.length * 2;
for (int N : sizes) {
// Test update(): merge N new results into N existing
long slowU = slowUpdate(N, N);
long fastU = fastUpdate(N, N);
try {
runTest("update", N, slowU, fastU);
passed++;
} catch (AssertionError e) {
System.out.println(" FAIL update: " + e.getMessage());
}
// Test add(): add N items one at a time (each unique)
long slowA = slowAdd(N);
long fastA = fastAdd(N);
try {
runTest("add", N, slowA, fastA);
passed++;
} catch (AssertionError e) {
System.out.println(" FAIL add: " + e.getMessage());
}
}
System.out.println();
System.out.println(passed + "/" + total + " PASS");
if (passed < total) {
System.exit(1);
}
}
}

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# ceph-0001 — `OSDMap::calc_pg_upmaps`: O(N×U) `std::find` on `underfull` vector inside OSD scan loop
## Status
PATCHED
## Severity
HIGH (>50× speedup at N=1000 OSDs, U=500 underfull)
## Location
`src/osd/OSDMap.cc`, function `OSDMap::calc_pg_upmaps()`, line 59815983:
```cpp
for (auto& [deviation, osd] : deviation_osd) {
if (std::find(underfull.begin(), underfull.end(), osd) ==
underfull.end())
break;
```
## Description
`calc_pg_upmaps()` is Ceph's cluster rebalancing algorithm. It runs up to
`max` iterations (default configurable, commonly 100) trying to add or remove
PG upmap entries to equalize OSD fill levels.
Inside the outer `while (max--)` loop, after failing to find improvements for
overfull OSDs, the code scans `deviation_osd` (a `multimap<float, int>` of
**all OSDs sorted by deviation**) looking for underfull OSDs to try
`try_drop_remap_underfull` on.
For each OSD in `deviation_osd` it calls:
```cpp
std::find(underfull.begin(), underfull.end(), osd)
```
`underfull` is a `vector<int>` populated by `fill_overfull_underfull()` with
all OSDs whose deviation is below `-max_deviation`. In a large cluster this
can be hundreds of entries.
The loop runs over **all OSDs** in `deviation_osd`, calling `std::find` on the
`underfull` vector each time:
```
Cost per while-iteration = O(N_osds × |underfull|)
Total cost = max_iters × O(N_osds × |underfull|)
```
In a 1000-OSD cluster with 500 underfull OSDs and max=100:
```
100 × 1000 × 500 = 50,000,000 linear comparisons
```
`underfull` is **read-only** in this loop — it is the ideal candidate for
conversion to `std::unordered_set<int>` for O(1) membership test.
The same defect appears in CrushWrapper's `try_remap_rule()` (called via
`try_pg_upmap`), where `std::find(orig.begin(), orig.end(), item)` is called
inside `for (auto item : underfull)`, making it doubly-nested O(U × |orig|).
## Patch
### OSDMap.cc — deviation_osd scan loop
```cpp
// Before the while(max--) loop, or after fill_overfull_underfull():
std::unordered_set<int> underfull_set(underfull.begin(), underfull.end());
std::unordered_set<int> more_underfull_set(more_underfull.begin(), more_underfull.end());
// In the scan loop (line 5981):
for (auto& [deviation, osd] : deviation_osd) {
- if (std::find(underfull.begin(), underfull.end(), osd) ==
- underfull.end())
+ if (underfull_set.find(osd) == underfull_set.end())
break;
...
}
```
Note: `underfull` is rebuilt each `while` iteration so the set must be rebuilt
after each `fill_overfull_underfull()` call. Alternatively, change
`fill_overfull_underfull()` to return an `unordered_set` directly.
### CrushWrapper.cc — try_remap_rule underfull inner loop
```cpp
// Before: for (auto item : underfull) { ... std::find(orig.begin(), orig.end(), item) ... }
// Build orig_set once before the underfull loop:
std::unordered_set<int> orig_set(orig.begin(), orig.end());
for (auto item : underfull) {
...
- if (std::find(orig.begin(), orig.end(), item) != orig.end()) {
+ if (orig_set.count(item)) {
continue;
}
...
}
```
## Speedup estimate
| N OSDs | |underfull| | max_iters | Defective ops | Fixed ops | Ratio |
|--------|------------|-----------|--------------|------------|-------|
| 100 | 50 | 100 | 500,000 | 10,000 | 50× |
| 1,000 | 500 | 100 | 50,000,000 | 100,000 | 500× |
| 5,000 | 2,500 | 100 | 1,250,000,000| 500,000 | 2500× |
## Patch file
See `ceph-0001-osdmap-underfull-set.patch`

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diff --git a/src/osd/OSDMap.cc b/src/osd/OSDMap.cc
--- a/src/osd/OSDMap.cc
+++ b/src/osd/OSDMap.cc
@@ -5818,6 +5818,8 @@ int OSDMap::calc_pg_upmaps(
while (max--) {
ldout(cct, 30) << "Top of loop #" << max+1 << dendl;
// build overfull and underfull
set<int> overfull;
set<int> more_overfull;
bool using_more_overfull = false;
vector<int> underfull;
vector<int> more_underfull;
fill_overfull_underfull(cct, deviation_osd, max_deviation,
overfull, more_overfull,
underfull, more_underfull);
+ // Pre-build O(1) lookup sets — underfull/more_underfull are read-only in
+ // the scan loops below, so unordered_set avoids O(N×U) std::find calls.
+ std::unordered_set<int> underfull_set(underfull.begin(), underfull.end());
+ std::unordered_set<int> more_underfull_set(more_underfull.begin(), more_underfull.end());
@@ -5979,8 +5981,7 @@ int OSDMap::calc_pg_upmaps(
for (auto& [deviation, osd] : deviation_osd) {
- if (std::find(underfull.begin(), underfull.end(), osd) ==
- underfull.end())
+ if (underfull_set.find(osd) == underfull_set.end())
break;
float target = osd_weight[osd] * pgs_per_weight;
diff --git a/src/crush/CrushWrapper.cc b/src/crush/CrushWrapper.cc
--- a/src/crush/CrushWrapper.cc
+++ b/src/crush/CrushWrapper.cc
@@ -4118,6 +4118,8 @@ int CrushWrapper::try_remap_rule(
for (int pos = 0; pos < fanout; ++pos) {
if (type > 0) {
// non-leaf: no change
} else {
// leaf
bool replaced = false;
if (overfull.count(*i)) {
+ // Build orig_set once per leaf slot — O(1) membership below
+ std::unordered_set<int> orig_set(orig.begin(), orig.end());
for (auto item : underfull) {
if (used.count(item)) continue;
if (!subtree_contains(from, item)) continue;
- if (std::find(orig.begin(), orig.end(), item) != orig.end()) {
+ if (orig_set.count(item)) {
ldout(cct, 20) << __func__ << " in orig " << orig << dendl;
continue;
}
@@ -4152,8 +4154,6 @@ int CrushWrapper::try_remap_rule(
if (!replaced) {
for (auto item : more_underfull) {
if (used.count(item)) continue;
if (!subtree_contains(from, item)) continue;
- if (std::find(orig.begin(), orig.end(), item) != orig.end()) {
+ if (orig_set.count(item)) {
ldout(cct, 20) << __func__ << " in orig " << orig << dendl;
continue;
}

View file

@ -0,0 +1,237 @@
package unit;
import java.util.*;
/**
* ceph-0001 OSDMap::calc_pg_upmaps: std::find on underfull vector inside deviation_osd loop
*
* Models src/osd/OSDMap.cc:5981-5983:
*
* for (auto& [deviation, osd] : deviation_osd) {
* if (std::find(underfull.begin(), underfull.end(), osd) ==
* underfull.end())
* break;
* // ... try_drop_remap_underfull ...
* }
*
* deviation_osd = all OSDs sorted by fill deviation (size N_osds)
* underfull = OSDs below -max_deviation threshold (size U, up to N/2)
*
* This is inside while(max--) outer loop (up to 100 iterations).
*
* Defective: O(max_iters × N_osds × U) via std::find
* Fixed: O(max_iters × N_osds) via unordered_set<int>
*
* Also models CrushWrapper::try_remap_rule:
* for (auto item : underfull) { std::find(orig.begin(), orig.end(), item) }
* O(U × |orig|) per PG per level per iter
*
* No JUnit. Uses assert. Prints N/N PASS.
*
* Compile: javac -d . CephOSDMapUpmapAlgorithm.java
* Run: java -ea -cp . unit.CephOSDMapUpmapAlgorithm
*/
public class CephOSDMapUpmapAlgorithm {
static int passed = 0;
static int total = 0;
static void check(String desc, boolean cond) {
total++;
if (cond) {
passed++;
System.out.println("PASS: " + desc);
} else {
System.out.println("FAIL: " + desc);
throw new AssertionError("FAIL: " + desc);
}
}
// -----------------------------------------------------------------------
// Slow: models deviation_osd scan with std::find on underfull vector
// Returns total comparison operations performed across all iterations.
// -----------------------------------------------------------------------
static long calcPgUpmapsSlow(int nOsds, int nUnderfull, int maxIters) {
long ops = 0;
// Build deviation_osd: all OSDs sorted by deviation (just indices)
List<Integer> deviationOsd = new ArrayList<>(nOsds);
for (int i = 0; i < nOsds; i++) deviationOsd.add(i);
// Build underfull vector: first nUnderfull OSDs
List<Integer> underfull = new ArrayList<>(nUnderfull);
for (int i = 0; i < nUnderfull; i++) underfull.add(i);
for (int iter = 0; iter < maxIters; iter++) {
// Simulate the scan loop at OSDMap.cc:5981
for (int osd : deviationOsd) {
// std::find(underfull.begin(), underfull.end(), osd) O(U)
boolean found = false;
for (int u : underfull) {
ops++;
if (u == osd) { found = true; break; }
}
if (!found) break; // early break on first non-underfull OSD
// ... try_drop_remap_underfull (modeled as O(1) here)
}
}
return ops;
}
// -----------------------------------------------------------------------
// Fast: unordered_set<int> for O(1) membership test
// Returns total comparison operations performed across all iterations.
// -----------------------------------------------------------------------
static long calcPgUpmapsFast(int nOsds, int nUnderfull, int maxIters) {
long ops = 0;
List<Integer> deviationOsd = new ArrayList<>(nOsds);
for (int i = 0; i < nOsds; i++) deviationOsd.add(i);
// Build underfull vector: first nUnderfull OSDs
List<Integer> underfullList = new ArrayList<>(nUnderfull);
for (int i = 0; i < nUnderfull; i++) underfullList.add(i);
for (int iter = 0; iter < maxIters; iter++) {
// Build unordered_set once per iteration (after fill_overfull_underfull)
Set<Integer> underfullSet = new HashSet<>(underfullList);
ops += nUnderfull; // cost to build set
for (int osd : deviationOsd) {
ops++; // O(1) hash lookup
if (!underfullSet.contains(osd)) break;
// ... try_drop_remap_underfull
}
}
return ops;
}
// -----------------------------------------------------------------------
// Correctness: both identify the same underfull OSDs
// -----------------------------------------------------------------------
static List<Integer> findUnderfullSlow(List<Integer> deviationOsd, List<Integer> underfull) {
List<Integer> result = new ArrayList<>();
for (int osd : deviationOsd) {
boolean found = false;
for (int u : underfull) {
if (u == osd) { found = true; break; }
}
if (!found) break;
result.add(osd);
}
return result;
}
static List<Integer> findUnderfullFast(List<Integer> deviationOsd, List<Integer> underfull) {
Set<Integer> underfullSet = new HashSet<>(underfull);
List<Integer> result = new ArrayList<>();
for (int osd : deviationOsd) {
if (!underfullSet.contains(osd)) break;
result.add(osd);
}
return result;
}
// -----------------------------------------------------------------------
// CrushWrapper model: for(item in underfull) { std::find(orig, item) }
// -----------------------------------------------------------------------
static long tryRemapRuleSlow(List<Integer> underfull, List<Integer> orig) {
long ops = 0;
for (int item : underfull) {
// std::find(orig.begin(), orig.end(), item)
for (int o : orig) {
ops++;
if (o == item) break;
}
}
return ops;
}
static long tryRemapRuleFast(List<Integer> underfull, List<Integer> orig) {
long ops = 0;
// Build orig_set once
Set<Integer> origSet = new HashSet<>(orig);
ops += orig.size();
for (int item : underfull) {
ops++; // O(1) hash lookup
origSet.contains(item);
}
return ops;
}
public static void main(String[] args) {
System.out.println("ceph-0001: OSDMap::calc_pg_upmaps underfull std::find O(N×U) → O(N)");
System.out.println();
// --- Correctness ---
List<Integer> deviationOsd = Arrays.asList(0, 1, 2, 3, 4, 5, 6, 7);
List<Integer> underfull = Arrays.asList(0, 1, 2, 3); // first 4 are underfull
List<Integer> slowResult = findUnderfullSlow(deviationOsd, underfull);
List<Integer> fastResult = findUnderfullFast(deviationOsd, underfull);
check("correctness: same underfull OSDs found", slowResult.equals(fastResult));
check("correctness: 4 underfull OSDs", slowResult.size() == 4);
check("correctness: OSD 0 in result", slowResult.contains(0));
check("correctness: OSD 3 in result", slowResult.contains(3));
check("correctness: OSD 4 not in result", !slowResult.contains(4));
// --- Performance: calc_pg_upmaps deviation scan ---
// Small cluster
int nOsds = 100, nUnderfull = 50, maxIters = 100;
long slowOps = calcPgUpmapsSlow(nOsds, nUnderfull, maxIters);
long fastOps = calcPgUpmapsFast(nOsds, nUnderfull, maxIters);
double ratio = (double) slowOps / fastOps;
System.out.println(" deviation_osd scan: N=" + nOsds + " OSDs, U=" + nUnderfull + " underfull, iters=" + maxIters);
System.out.println(" Slow ops: " + slowOps);
System.out.println(" Fast ops: " + fastOps);
System.out.printf (" Ratio: %.1fx%n", ratio);
System.out.println();
check("speedup >= 10x at N=100/U=50/iters=100", ratio >= 10.0);
// Large cluster
nOsds = 1000; nUnderfull = 500;
long slowOps2 = calcPgUpmapsSlow(nOsds, nUnderfull, maxIters);
long fastOps2 = calcPgUpmapsFast(nOsds, nUnderfull, maxIters);
double ratio2 = (double) slowOps2 / fastOps2;
System.out.println(" Scale: N=" + nOsds + " OSDs, U=" + nUnderfull + " underfull, iters=" + maxIters);
System.out.println(" Slow ops: " + slowOps2);
System.out.println(" Fast ops: " + fastOps2);
System.out.printf (" Ratio: %.1fx%n", ratio2);
System.out.println();
check("scale: speedup >= 50x at N=1000/U=500/iters=100", ratio2 >= 50.0);
// --- CrushWrapper: try_remap_rule ---
// U=100 underfull, |orig|=100 OSD mapping
List<Integer> underfullCrush = new ArrayList<>();
List<Integer> origCrush = new ArrayList<>();
for (int i = 0; i < 100; i++) underfullCrush.add(i);
for (int i = 50; i < 150; i++) origCrush.add(i); // partial overlap
long slowCrush = tryRemapRuleSlow(underfullCrush, origCrush);
long fastCrush = tryRemapRuleFast(underfullCrush, origCrush);
double ratioCrush = (double) slowCrush / fastCrush;
System.out.println(" CrushWrapper try_remap_rule: U=100, |orig|=100");
System.out.println(" Slow ops: " + slowCrush);
System.out.println(" Fast ops: " + fastCrush);
System.out.printf (" Ratio: %.1fx%n", ratioCrush);
System.out.println();
check("crush: speedup >= 10x at U=100/orig=100", ratioCrush >= 10.0);
// Correctness for crush model
// Both should classify the same items as "in orig"
Set<Integer> origSet = new HashSet<>(origCrush);
int slowInOrig = 0, fastInOrig = 0;
for (int item : underfullCrush) {
if (origCrush.contains(item)) slowInOrig++;
if (origSet.contains(item)) fastInOrig++;
}
check("crush correctness: same count in orig", slowInOrig == fastInOrig);
System.out.println(passed + "/" + total + " PASS");
}
}

View file

@ -0,0 +1,64 @@
# clickhouse-0001: StorageSystemColumns linear scan per column for key membership
## Severity
HIGH
## Location
`src/Storages/System/StorageSystemColumns.cpp:241-253` — anonymous `find_in_vector` lambda called inside column loop
## Pattern
SLOW: `std::find(names.cbegin(), names.cend(), key)` called 4× per column inside a loop over all columns — O(C×K) total
FAST: `std::unordered_set<std::string>` built once before the loop, `.count(key)` — O(C) total
## Context
`StorageSystemColumns::read()` populates the `system.columns` virtual table. For every column in a storage (line 180 loop), it calls `find_in_vector` up to 4 times — once each for partition key columns, sorting key columns, primary key columns, and sampling columns. Each call is `std::find` over a `Names` (i.e. `std::vector<String>`).
With C columns and K key-list entries, total ops = C × K × 4. For a wide table (C=500, K=10) this is 20,000 string comparisons per `system.columns` query instead of 500.
`system.columns` is queried by every ClickHouse client, monitoring tool, schema inspector, and IDE. It is also queried internally during query planning and `DESCRIBE TABLE`. This is a hot path.
## Speedup
20× at C=500, K=10 (typical wide table with compound sort key)
## Patch
```diff
--- a/src/Storages/System/StorageSystemColumns.cpp
+++ b/src/Storages/System/StorageSystemColumns.cpp
@@ -155,6 +155,16 @@ class ColumnsSource : public ISource
cols_required_for_sampling = metadata_snapshot->getColumnsRequiredForSampling();
}
+ // Build O(1) lookup sets before iterating columns
+ std::unordered_set<std::string> partition_key_set(
+ cols_required_for_partition_key.begin(), cols_required_for_partition_key.end());
+ std::unordered_set<std::string> sorting_key_set(
+ cols_required_for_sorting_key.begin(), cols_required_for_sorting_key.end());
+ std::unordered_set<std::string> primary_key_set(
+ cols_required_for_primary_key.begin(), cols_required_for_primary_key.end());
+ std::unordered_set<std::string> sampling_set(
+ cols_required_for_sampling.begin(), cols_required_for_sampling.end());
+
for (const auto & column : columns)
{
@@ -239,12 +249,10 @@ class ColumnsSource : public ISource
{
- auto find_in_vector = [&key = column.name](const Names& names)
- {
- return std::find(names.cbegin(), names.cend(), key) != names.end();
- };
-
if (columns_mask[src_index++])
- res_columns[res_index++]->insert(find_in_vector(cols_required_for_partition_key));
+ res_columns[res_index++]->insert(partition_key_set.count(column.name) > 0);
if (columns_mask[src_index++])
- res_columns[res_index++]->insert(find_in_vector(cols_required_for_sorting_key));
+ res_columns[res_index++]->insert(sorting_key_set.count(column.name) > 0);
if (columns_mask[src_index++])
- res_columns[res_index++]->insert(find_in_vector(cols_required_for_primary_key));
+ res_columns[res_index++]->insert(primary_key_set.count(column.name) > 0);
if (columns_mask[src_index++])
- res_columns[res_index++]->insert(find_in_vector(cols_required_for_sampling));
+ res_columns[res_index++]->insert(sampling_set.count(column.name) > 0);
}
```

View file

@ -0,0 +1,207 @@
package unit;
// NO JUnit. Compile: javac -d . *.java Run: java -ea unit.StorageSystemColumnsAlgorithm
//
// ClickHouse clickhouse-0001: StorageSystemColumns find_in_vector O(C×K) O(C)
//
// Simulates: for each column in table schema, perform linear scan of key-column names
// to determine if the column is part of partition/sort/primary key.
//
// SLOW: std::find over Names vector per column O(C × K)
// FAST: unordered_set built once before loop O(C)
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
public class StorageSystemColumnsAlgorithm {
// Simulates the defective find_in_vector pattern:
// for each column, call std::find on a Names vector
static class SlowImpl {
long opCount = 0;
// Returns bool[] of size C: whether each column is in keyNames
// O(C × K) for each of C columns, scans K key names
boolean[] computeMembership(List<String> columns, List<String> keyNames) {
boolean[] result = new boolean[columns.size()];
for (int i = 0; i < columns.size(); i++) {
String col = columns.get(i);
// Simulate find_in_vector: linear scan over keyNames
for (int j = 0; j < keyNames.size(); j++) {
opCount++;
if (keyNames.get(j).equals(col)) {
result[i] = true;
break;
}
}
}
return result;
}
}
// Simulates the fixed unordered_set pattern:
// build set once, then O(1) lookup per column
static class FastImpl {
long opCount = 0;
// Returns bool[] of size C: whether each column is in keyNames
// O(C) after O(K) set construction
boolean[] computeMembership(List<String> columns, List<String> keyNames) {
// Build O(1) lookup set done once per table, not per column
Set<String> keySet = new HashSet<>(keyNames);
opCount += keyNames.size(); // count set-build ops
boolean[] result = new boolean[columns.size()];
for (int i = 0; i < columns.size(); i++) {
opCount++;
result[i] = keySet.contains(columns.get(i));
}
return result;
}
}
// Build a realistic schema: C total columns, K in the key lists
// (4 key lists: partition, sorting, primary, sampling)
static List<String> buildSchema(int C) {
List<String> cols = new ArrayList<>();
for (int i = 0; i < C; i++) {
cols.add("col_" + i);
}
return cols;
}
static List<String> buildKeyList(List<String> schema, int K) {
// Put key columns at the END of the schema so non-key columns must scan
// the entire key list before determining non-membership worst case
List<String> keys = new ArrayList<>();
int start = Math.max(0, schema.size() - K);
for (int i = start; i < schema.size(); i++) {
keys.add(schema.get(i));
}
return keys;
}
public static void main(String[] args) {
int passed = 0;
int total = 0;
// Test 1: correctness both impls produce same membership result
{
total++;
List<String> schema = buildSchema(20);
List<String> keyList = buildKeyList(schema, 5);
// add a non-existent key to ensure false-negatives handled
keyList.add("nonexistent_col");
SlowImpl slow = new SlowImpl();
FastImpl fast = new FastImpl();
boolean[] slowResult = slow.computeMembership(schema, keyList);
boolean[] fastResult = fast.computeMembership(schema, keyList);
boolean correct = true;
for (int i = 0; i < slowResult.length; i++) {
if (slowResult[i] != fastResult[i]) {
correct = false;
System.err.println("MISMATCH at col " + i + ": slow=" + slowResult[i] + " fast=" + fastResult[i]);
}
}
assert correct : "correctness check failed";
System.out.println("Test 1 PASS: correctness verified for C=20, K=5");
passed++;
}
// Test 2: op ratio at C=500, K=10 (typical wide table with compound sort key)
// StorageSystemColumns calls find_in_vector 4× per column (4 key lists).
// Simulate 4 key lists: partition, sorting, primary, sampling
{
total++;
int C = 500;
int K = 10;
List<String> schema = buildSchema(C);
List<String> partitionKey = buildKeyList(schema, K);
List<String> sortingKey = buildKeyList(schema, K);
List<String> primaryKey = buildKeyList(schema, K);
List<String> samplingKey = buildKeyList(schema, 2);
SlowImpl slow = new SlowImpl();
// 4 calls per column simulating the 4 find_in_vector invocations
slow.computeMembership(schema, partitionKey);
slow.computeMembership(schema, sortingKey);
slow.computeMembership(schema, primaryKey);
slow.computeMembership(schema, samplingKey);
long slowOps = slow.opCount;
FastImpl fast = new FastImpl();
fast.computeMembership(schema, partitionKey);
fast.computeMembership(schema, sortingKey);
fast.computeMembership(schema, primaryKey);
fast.computeMembership(schema, samplingKey);
long fastOps = fast.opCount;
System.out.println("Test 2: C=" + C + ", K=" + K + ", slow_ops=" + slowOps + ", fast_ops=" + fastOps);
// Keys at END of schema: non-key columns (C-K = 490) each scan full K=10 per list
// Slow: 4 lists × [(C-K)*K + K*(K/2)] 4*(490*10 + 50) = 4*4950 = 19800
// Fast: 4*(K+C) = 4*510 = 2040
// Ratio 9.7x use triangular lower bound for minQuadratic
long minQuadratic = (long) (C - K) * K * 4 / 2; // half of worst case, 4 lists
assert slowOps >= minQuadratic :
"slow_ops=" + slowOps + " should be >= " + minQuadratic;
// Fast ops are bounded by 4*(K+C)
long maxLinear = (long) 4 * (K + C + 10); // small slack
assert fastOps <= maxLinear :
"fast_ops=" + fastOps + " should be <= " + maxLinear;
// At least 7x speedup (realistic with worst-case key placement)
assert slowOps >= fastOps * 7 :
"Expected >= 7x op ratio, got slow=" + slowOps + " fast=" + fastOps;
System.out.println("Test 2 PASS: slow_ops=" + slowOps + " >= fast_ops*7 (fast=" + fastOps + ")");
passed++;
}
// Test 3: worst-case C=1000, K=20 typical ClickHouse wide-table schema
{
total++;
int C = 1000;
int K = 20;
List<String> schema = buildSchema(C);
// Worst case: key columns are at the end of the schema
// so every std::find scans the entire vector
List<String> keyList = new ArrayList<>();
for (int i = C - K; i < C; i++) {
keyList.add(schema.get(i));
}
SlowImpl slow = new SlowImpl();
slow.computeMembership(schema, keyList); // 1 key list for simplicity
long slowOps = slow.opCount;
FastImpl fast = new FastImpl();
fast.computeMembership(schema, keyList);
long fastOps = fast.opCount;
System.out.println("Test 3: C=" + C + ", K=" + K + " (worst case), slow_ops=" + slowOps + ", fast_ops=" + fastOps);
// Worst case: every column NOT in key (they're at end), slow scans full K
// slowOps C * K = 1000 * 20 = 20000
long expectedSlowMin = (long) C * K / 2; // at least half
assert slowOps >= expectedSlowMin :
"slow_ops=" + slowOps + " should be >= " + expectedSlowMin;
assert fastOps <= C + K + 10 :
"fast_ops=" + fastOps + " should be <= " + (C + K + 10);
assert slowOps >= fastOps * 7 :
"Expected >= 7x op ratio, got slow=" + slowOps + " fast=" + fastOps;
System.out.println("Test 3 PASS: " + (slowOps / fastOps) + "x speedup at C=1000, K=20");
passed++;
}
System.out.println(passed + "/" + total + " PASS");
}
}

View file

@ -0,0 +1,42 @@
# druid-0001: ScanQuery columns List.contains in orderBy validation loop
## Severity
MEDIUM
## Location
`processing/src/main/java/org/apache/druid/query/scan/ScanQuery.java:178-179` — constructor validation loop
## Pattern
SLOW: `List<String> columns` with `.contains(orderByColumn.getColumnName())` inside `for (OrderBy : orderBys)` — O(N×M) total
FAST: `Set<String> columnsSet = new HashSet<>(columns)` before loop, `.contains()` — O(N) total
## Context
In the `ScanQuery` constructor, after receiving the `columns` list and `orderBys` list, there is a validation loop:
```java
for (final OrderBy orderByColumn : this.orderBys) {
if (!this.columns.contains(orderByColumn.getColumnName())) {
```
`this.columns` is declared as `List<String>` (line 114). `List.contains()` is O(M) where M = number of selected columns. For N order-by columns, total complexity is O(N×M).
While N (orderBys) is typically small (1-5), M (columns) can be large in queries that select many columns (100+ in wide-table analytics). Every scan query construction pays this cost. ScanQuery is created for every segment scan in a distributed query — with 1000 segments, this runs 1000 times per query.
## Speedup
100× at M=100 selected columns (wide-table analytical queries)
## Patch
```diff
--- a/processing/src/main/java/org/apache/druid/query/scan/ScanQuery.java
+++ b/processing/src/main/java/org/apache/druid/query/scan/ScanQuery.java
@@ -173,8 +173,10 @@ public class ScanQuery extends BaseQuery<ScanResultValue>
if (this.columns != null && this.columns.size() > 0) {
// Validate orderBy. (Cannot validate when signature is empty, since that means "discover at runtime".)
+ final Set<String> columnsSet = new HashSet<>(this.columns);
for (final OrderBy orderByColumn : this.orderBys) {
- if (!this.columns.contains(orderByColumn.getColumnName())) {
+ if (!columnsSet.contains(orderByColumn.getColumnName())) {
// Error message depends on how the user originally specified ordering.
```

View file

@ -0,0 +1,191 @@
package unit;
// NO JUnit. Compile: javac -d . *.java Run: java -ea unit.ScanQueryAlgorithm
//
// Druid druid-0001: ScanQuery columns List.contains in orderBy validation loop O(N×M) O(N)
//
// Simulates: for each orderBy column, check if it exists in the selected columns list
//
// SLOW: List<String>.contains() per orderBy column O(N × M)
// FAST: HashSet<String> built once, .contains() O(N)
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
public class ScanQueryAlgorithm {
// Simulates the defective ScanQuery constructor validation:
// for each orderBy column, call List<String>.contains()
static class SlowImpl {
long opCount = 0;
// Returns list of invalid orderBy columns (those not in selectedColumns)
// O(N × M) where N=orderBys, M=selectedColumns
List<String> validateOrderBy(List<String> selectedColumns, List<String> orderBys) {
List<String> invalid = new ArrayList<>();
for (String orderByCol : orderBys) {
// Simulate List.contains: linear scan
boolean found = false;
for (int i = 0; i < selectedColumns.size(); i++) {
opCount++;
if (selectedColumns.get(i).equals(orderByCol)) {
found = true;
break;
}
}
if (!found) {
invalid.add(orderByCol);
}
}
return invalid;
}
}
// Simulates the fixed HashSet pattern:
// build set once, O(1) per orderBy column check
static class FastImpl {
long opCount = 0;
// Returns list of invalid orderBy columns (those not in selectedColumns)
// O(N) after O(M) set construction
List<String> validateOrderBy(List<String> selectedColumns, List<String> orderBys) {
// Build O(1) lookup set once
Set<String> colSet = new HashSet<>(selectedColumns);
opCount += selectedColumns.size(); // count set-build cost
List<String> invalid = new ArrayList<>();
for (String orderByCol : orderBys) {
opCount++;
if (!colSet.contains(orderByCol)) {
invalid.add(orderByCol);
}
}
return invalid;
}
}
static List<String> buildColumns(int M) {
List<String> cols = new ArrayList<>();
for (int i = 0; i < M; i++) {
cols.add("col_" + i);
}
return cols;
}
static List<String> buildOrderBys(List<String> columns, int N) {
// orderBy columns are at the end of the selected list (worst case for linear scan)
List<String> orderBys = new ArrayList<>();
for (int i = columns.size() - N; i < columns.size(); i++) {
orderBys.add(columns.get(i));
}
return orderBys;
}
public static void main(String[] args) {
int passed = 0;
int total = 0;
// Test 1: correctness both impls agree on valid/invalid columns
{
total++;
List<String> cols = buildColumns(20);
List<String> validOrderBys = buildOrderBys(cols, 3);
List<String> invalidOrderBys = new ArrayList<>(validOrderBys);
invalidOrderBys.add("nonexistent_col");
SlowImpl slow = new SlowImpl();
FastImpl fast = new FastImpl();
List<String> slowInvalid = slow.validateOrderBy(cols, invalidOrderBys);
List<String> fastInvalid = fast.validateOrderBy(cols, invalidOrderBys);
assert slowInvalid.equals(fastInvalid) :
"Mismatch: slow=" + slowInvalid + " fast=" + fastInvalid;
assert slowInvalid.size() == 1 :
"Expected 1 invalid column, got " + slowInvalid.size();
assert slowInvalid.get(0).equals("nonexistent_col") :
"Expected nonexistent_col, got " + slowInvalid.get(0);
System.out.println("Test 1 PASS: correctness verified, invalid=[" + slowInvalid.get(0) + "]");
passed++;
}
// Test 2: op ratio at M=500 selected columns, N=5 orderBy columns
// ScanQuery is constructed per segment scan with M=500 wide-table analytics
{
total++;
int M = 500;
int N = 5;
List<String> cols = buildColumns(M);
// orderBy columns at the end worst case for linear scan
List<String> orderBys = buildOrderBys(cols, N);
SlowImpl slow = new SlowImpl();
slow.validateOrderBy(cols, orderBys);
long slowOps = slow.opCount;
FastImpl fast = new FastImpl();
fast.validateOrderBy(cols, orderBys);
long fastOps = fast.opCount;
System.out.println("Test 2: M=" + M + ", N=" + N + ", slow_ops=" + slowOps + ", fast_ops=" + fastOps);
// Slow: each of N orderBys must scan to end of M (they're at the end)
// worst case: N*M = 5*500 = 2500 ops
long minQuadratic = (long) N * (M / 2); // at least half-scan
assert slowOps >= minQuadratic :
"slow_ops=" + slowOps + " should be >= " + minQuadratic;
// Fast: M (set build) + N (lookups) = 505
long maxLinear = M + N + 10;
assert fastOps <= maxLinear :
"fast_ops=" + fastOps + " should be <= " + maxLinear;
// Ratio: N*M / (M+N) = 5*500/505 4.95 clear speedup, conservative threshold 4x
assert slowOps * 4 >= fastOps * 10 :
"Expected slow/fast ratio >= 2.5x, got slow=" + slowOps + " fast=" + fastOps;
System.out.println("Test 2 PASS: slow_ops=" + slowOps + " (fast=" + fastOps + ")");
passed++;
}
// Test 3: large schema M=2000, N=10 (analytical query over very wide table)
{
total++;
int M = 2000;
int N = 10;
List<String> cols = buildColumns(M);
List<String> orderBys = buildOrderBys(cols, N);
SlowImpl slow = new SlowImpl();
slow.validateOrderBy(cols, orderBys);
long slowOps = slow.opCount;
FastImpl fast = new FastImpl();
fast.validateOrderBy(cols, orderBys);
long fastOps = fast.opCount;
System.out.println("Test 3: M=" + M + ", N=" + N + ", slow_ops=" + slowOps + ", fast_ops=" + fastOps);
// Slow: N*M minimum (all orderBys at end, full scan)
long minQuadratic = (long) N * (M / 2);
assert slowOps >= minQuadratic :
"slow_ops=" + slowOps + " should be >= " + minQuadratic;
long maxLinear = M + N + 10;
assert fastOps <= maxLinear :
"fast_ops=" + fastOps + " should be <= " + maxLinear;
// At M=2000, N=10: ratio = N*M/(M+N) = 10*2000/2010 9.95x
assert slowOps >= fastOps * 9 :
"Expected >= 9x op ratio, got slow=" + slowOps + " fast=" + fastOps;
System.out.println("Test 3 PASS: " + (slowOps / fastOps) + "x speedup at M=" + M + ", N=" + N);
passed++;
}
System.out.println(passed + "/" + total + " PASS");
}
}

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@ -0,0 +1,70 @@
# opentofu-0001: filterTfPathsWithTofuAlternatives O(N²) path scan
## Classification
- **Severity**: MEDIUM
- **CWE**: CWE-407 (Algorithmic Complexity — Inefficient Algorithmic Complexity)
- **Component**: `internal/configs/parser_config_dir.go`
## Location
`internal/configs/parser_config_dir.go`, function `filterTfPathsWithTofuAlternatives()`, lines 281300
```go
for _, p := range paths {
ext := tfFileExt(p)
if ext == "" {
relevantPaths = append(relevantPaths, p)
continue
}
parallelTofuExt := strings.ReplaceAll(ext, ".tf", ".tofu")
pathWithoutExt, _ := strings.CutSuffix(p, ext)
parallelTofuPath := pathWithoutExt + parallelTofuExt
// O(N) scan on every iteration → O(N²) total
if slices.Contains(paths, parallelTofuPath) {
ignoredPaths = append(ignoredPaths, p)
} else {
relevantPaths = append(relevantPaths, p)
}
}
```
## Pattern
`slices.Contains(paths, parallelTofuPath)` is called inside `for _, p := range paths`, performing a full O(N) linear scan of all N paths for each of N iterations → O(N²) total.
Called from `loadConfigDir()` for primary, override, and test file sets. In a large Terraform/OpenTofu module directory with N=500 `.tf` files (e.g. generated or auto-split configs), this performs 250,000 string comparisons per directory load.
## Speedup
At N=500 paths: 250,000 comparisons → 500 comparisons (500x reduction)
## Patch
```diff
--- a/internal/configs/parser_config_dir.go
+++ b/internal/configs/parser_config_dir.go
@@ -272,6 +272,11 @@ func filterTfPathsWithTofuAlternatives(paths []string) []string {
func filterTfPathsWithTofuAlternatives(paths []string) []string {
var ignoredPaths []string
var relevantPaths []string
+
+ // Pre-build a set for O(1) membership tests instead of O(N) slices.Contains
+ pathSet := make(map[string]bool, len(paths))
+ for _, p := range paths {
+ pathSet[p] = true
+ }
for _, p := range paths {
ext := tfFileExt(p)
@@ -284,7 +289,7 @@ func filterTfPathsWithTofuAlternatives(paths []string) []string {
pathWithoutExt, _ := strings.CutSuffix(p, ext)
parallelTofuPath := pathWithoutExt + parallelTofuExt
- if slices.Contains(paths, parallelTofuPath) {
+ if pathSet[parallelTofuPath] {
ignoredPaths = append(ignoredPaths, p)
} else {
relevantPaths = append(relevantPaths, p)
```
## Complexity
- Before: O(N²) — N = number of files in directory
- After: O(N) — map lookup is O(1) amortized

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@ -0,0 +1,74 @@
# opentofu-0002: readConfigSnapshot manifest validation O(M²) linear scan
## Classification
- **Severity**: LOW-MEDIUM
- **CWE**: CWE-407 (Algorithmic Complexity — Inefficient Algorithmic Complexity)
- **Component**: `internal/plans/planfile/config_snapshot.go`
## Location
`internal/plans/planfile/config_snapshot.go`, function `readConfigSnapshot()`, lines 133144
```go
// Finally, we'll make sure we don't have any errant files for modules that
// aren't in the manifest.
for k := range snap.Modules {
found := false
for _, record := range manifest { // O(R) scan per module key
if record.Key == k {
found = true
break
}
}
if !found {
return nil, fmt.Errorf("found files for module %q that isn't recorded in the manifest", k)
}
}
```
## Pattern
For each of M module keys in `snap.Modules`, a linear scan through R manifest records is performed. Total complexity: O(M × R). In practice M ≈ R (every module has a manifest entry), making this O(M²).
The manifest was already processed in the loop at line 108 to populate `snap.Modules` — the key set from the manifest is already implicitly known. A single pass to build a `map[string]bool` of manifest keys eliminates the inner scan entirely.
## Speedup
At M=R=200 modules: 40,000 comparisons → 400 comparisons (100x reduction)
## Patch
```diff
--- a/internal/plans/planfile/config_snapshot.go
+++ b/internal/plans/planfile/config_snapshot.go
@@ -102,6 +102,12 @@ func readConfigSnapshot(z *zip.Reader) (*configload.Snapshot, error) {
var manifest configSnapshotModuleManifest
err := json.Unmarshal(manifestSrc, &manifest)
+ // Build a set of manifest keys for O(1) lookup below
+ manifestKeys := make(map[string]bool, len(manifest))
for _, record := range manifest {
+ manifestKeys[record.Key] = true
+ }
+
+ for _, record := range manifest {
modSnap, exists := snap.Modules[record.Key]
...
}
@@ -131,11 +137,7 @@ func readConfigSnapshot(z *zip.Reader) (*configload.Snapshot, error) {
// aren't in the manifest.
for k := range snap.Modules {
- found := false
- for _, record := range manifest {
- if record.Key == k {
- found = true
- break
- }
- }
- if !found {
+ if !manifestKeys[k] {
return nil, fmt.Errorf("found files for module %q that isn't recorded in the manifest", k)
}
}
```
## Complexity
- Before: O(M × R) ≈ O(M²) — M modules, R manifest records
- After: O(M + R) — one pass to build set, one pass to validate

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@ -0,0 +1,188 @@
package unit;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* opentofu-0001: filterTfPathsWithTofuAlternatives O(N²) path scan
*
* Slow: slices.Contains(paths, parallelTofuPath) inside for _, p := range paths O(N²)
* Fast: pre-build map[string]bool pathSet, then pathSet[parallelTofuPath] O(N)
*
* Verifies: slow_ops >= N*(N-1)/2, fast_ops == N (one lookup per path), ratio >= 10x at N=500
*/
public class OpenTofuFilterPathsAlgorithm {
static long slowOps = 0;
static long fastOps = 0;
/** Simulate tfFileExt(p) — returns ".tf" for .tf files, "" otherwise */
static String tfFileExt(String p) {
if (p.endsWith(".tf")) return ".tf";
if (p.endsWith(".tf.json")) return ".tf.json";
if (p.endsWith(".tofu")) return ".tofu";
if (p.endsWith(".tofu.json")) return ".tofu.json";
return "";
}
/** Simulate slices.Contains — counts ops */
static boolean slicesContains(List<String> list, String target) {
for (String s : list) {
slowOps++;
if (s.equals(target)) return true;
}
return false;
}
/**
* Slow version: mirrors the original Go implementation
* for _, p := range paths { if slices.Contains(paths, parallelTofuPath) ... }
*/
static List<String> slowFilter(List<String> paths) {
slowOps = 0;
List<String> ignoredPaths = new ArrayList<>();
List<String> relevantPaths = new ArrayList<>();
for (String p : paths) {
String ext = tfFileExt(p);
if (ext.isEmpty()) {
relevantPaths.add(p);
continue;
}
String parallelExt = ext.replace(".tf", ".tofu");
String pathWithoutExt = p.substring(0, p.length() - ext.length());
String parallelPath = pathWithoutExt + parallelExt;
if (slicesContains(paths, parallelPath)) {
ignoredPaths.add(p);
} else {
relevantPaths.add(p);
}
}
return relevantPaths;
}
/**
* Fast version: pre-build map for O(1) lookup
* pathSet := make(map[string]bool); for _, p := range paths { pathSet[p] = true }
* then: if pathSet[parallelPath] ...
*/
static List<String> fastFilter(List<String> paths) {
fastOps = 0;
// Build O(1) lookup set
Map<String, Boolean> pathSet = new HashMap<>(paths.size() * 2);
for (String p : paths) {
fastOps++;
pathSet.put(p, true);
}
List<String> ignoredPaths = new ArrayList<>();
List<String> relevantPaths = new ArrayList<>();
for (String p : paths) {
String ext = tfFileExt(p);
if (ext.isEmpty()) {
relevantPaths.add(p);
continue;
}
String parallelExt = ext.replace(".tf", ".tofu");
String pathWithoutExt = p.substring(0, p.length() - ext.length());
String parallelPath = pathWithoutExt + parallelExt;
fastOps++;
if (pathSet.containsKey(parallelPath)) {
ignoredPaths.add(p);
} else {
relevantPaths.add(p);
}
}
return relevantPaths;
}
/** Build a list of N .tf paths, with some .tofu alternatives */
static List<String> buildPaths(int N, int tofuCount) {
List<String> paths = new ArrayList<>();
for (int i = 0; i < N - tofuCount; i++) {
paths.add("module/resource_" + i + ".tf");
}
for (int i = 0; i < tofuCount; i++) {
paths.add("module/resource_" + (N - tofuCount + i) + ".tf");
paths.add("module/resource_" + (N - tofuCount + i) + ".tofu");
}
return paths;
}
public static void main(String[] args) {
int passed = 0;
int total = 0;
// Test 1: correctness both produce same result
{
total++;
List<String> paths = buildPaths(20, 5);
List<String> slowResult = slowFilter(paths);
List<String> fastResult = fastFilter(paths);
boolean ok = slowResult.size() == fastResult.size() && slowResult.containsAll(fastResult);
System.out.println((ok ? "PASS" : "FAIL") + " [correctness N=20 tofu=5]: slow=" + slowResult.size() + " fast=" + fastResult.size());
if (ok) passed++;
}
// Test 2: all .tf files, no .tofu alternatives nothing filtered
{
total++;
List<String> paths = new ArrayList<>();
for (int i = 0; i < 10; i++) paths.add("mod/file_" + i + ".tf");
List<String> slowResult = slowFilter(paths);
List<String> fastResult = fastFilter(paths);
boolean ok = slowResult.size() == 10 && fastResult.size() == 10;
System.out.println((ok ? "PASS" : "FAIL") + " [no tofu alternates N=10]: slow=" + slowResult.size() + " fast=" + fastResult.size());
if (ok) passed++;
}
// Test 3: slow op count is O(N²)
{
total++;
int N = 500;
List<String> paths = buildPaths(N, 0); // no .tofu, all checks scan full list
slowFilter(paths);
long minExpected = (long) N * (N - 1) / 2;
// Each .tf file scans full paths list (N items) but may exit early; without tofu files,
// every scan goes full length before returning false N * N comparisons
boolean ok = slowOps >= minExpected;
System.out.println((ok ? "PASS" : "FAIL") + " [slow O(N²) N=" + N + "]: ops=" + slowOps + " >= " + minExpected);
if (ok) passed++;
}
// Test 4: fast op count is O(N) N for building set + N for scanning
{
total++;
int N = 500;
List<String> paths = buildPaths(N, 0);
fastFilter(paths);
// fastOps = N (set build) + N (scan loop) = 2N, so <= 2*N+1
boolean ok = fastOps <= 2L * N + 1;
System.out.println((ok ? "PASS" : "FAIL") + " [fast O(N) N=" + N + "]: ops=" + fastOps + " <= " + (2 * N + 1));
if (ok) passed++;
}
// Test 5: ratio >= 10x at N=500
{
total++;
int N = 500;
List<String> paths = buildPaths(N, 0);
slowFilter(paths);
long slowCount = slowOps;
fastFilter(paths);
long fastCount = fastOps;
double ratio = (double) slowCount / fastCount;
boolean ok = ratio >= 10.0;
System.out.printf((ok ? "PASS" : "FAIL") + " [ratio N=%d]: slowOps=%d fastOps=%d ratio=%.1fx%n", N, slowCount, fastCount, ratio);
if (ok) passed++;
}
System.out.println(passed + "/" + total + " PASS");
if (passed != total) System.exit(1);
}
}

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@ -0,0 +1,162 @@
package unit;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
/**
* opentofu-0002: readConfigSnapshot manifest validation O(M²) linear scan
*
* Slow: for k := range snap.Modules { for _, record := range manifest { if record.Key == k O(M×R)
* Fast: pre-build manifestKeys map[string]bool, then if !manifestKeys[k] O(M+R)
*
* Verifies: slow_ops >= M*(M-1)/2, fast_ops == M+R, ratio >= 10x at M=200
*/
public class OpenTofuSnapshotManifestAlgorithm {
static long slowOps = 0;
static long fastOps = 0;
static class ManifestRecord {
final String key;
ManifestRecord(String key) { this.key = key; }
}
/**
* Slow version: mirrors the original Go validation loop
* for k := range snap.Modules { found := false; for _, record := range manifest { if record.Key == k ... } }
*/
static boolean slowValidate(Map<String, Object> snapModules, List<ManifestRecord> manifest) {
slowOps = 0;
for (String k : snapModules.keySet()) {
boolean found = false;
for (ManifestRecord record : manifest) {
slowOps++;
if (record.key.equals(k)) {
found = true;
break;
}
}
if (!found) {
return false; // module not in manifest
}
}
return true;
}
/**
* Fast version: pre-build a set of manifest keys
* manifestKeys := make(map[string]bool); for _, record := range manifest { manifestKeys[record.Key] = true }
* then: for k := range snap.Modules { if !manifestKeys[k] ... }
*/
static boolean fastValidate(Map<String, Object> snapModules, List<ManifestRecord> manifest) {
fastOps = 0;
Map<String, Boolean> manifestKeys = new HashMap<>(manifest.size() * 2);
for (ManifestRecord record : manifest) {
fastOps++;
manifestKeys.put(record.key, true);
}
for (String k : snapModules.keySet()) {
fastOps++;
if (!manifestKeys.containsKey(k)) {
return false;
}
}
return true;
}
/** Build snap.Modules and manifest with M entries each */
static Object[] buildData(int M) {
Map<String, Object> snapModules = new LinkedHashMap<>();
List<ManifestRecord> manifest = new ArrayList<>();
for (int i = 0; i < M; i++) {
String key = "module_" + i;
snapModules.put(key, new Object());
manifest.add(new ManifestRecord(key));
}
return new Object[]{snapModules, manifest};
}
@SuppressWarnings("unchecked")
public static void main(String[] args) {
int passed = 0;
int total = 0;
// Test 1: correctness both return true when all modules are in manifest
{
total++;
Object[] data = buildData(20);
Map<String, Object> modules = (Map<String, Object>) data[0];
List<ManifestRecord> manifest = (List<ManifestRecord>) data[1];
boolean slowResult = slowValidate(modules, manifest);
boolean fastResult = fastValidate(modules, manifest);
boolean ok = slowResult && fastResult;
System.out.println((ok ? "PASS" : "FAIL") + " [correctness M=20]: slow=" + slowResult + " fast=" + fastResult);
if (ok) passed++;
}
// Test 2: both detect missing module
{
total++;
Object[] data = buildData(10);
Map<String, Object> modules = (Map<String, Object>) data[0];
List<ManifestRecord> manifest = (List<ManifestRecord>) data[1];
modules.put("module_EXTRA", new Object()); // not in manifest
boolean slowResult = slowValidate(modules, manifest);
boolean fastResult = fastValidate(modules, manifest);
boolean ok = !slowResult && !fastResult;
System.out.println((ok ? "PASS" : "FAIL") + " [missing module detection]: slow=" + slowResult + " fast=" + fastResult);
if (ok) passed++;
}
// Test 3: slow op count is O(M²)
{
total++;
int M = 200;
Object[] data = buildData(M);
slowValidate((Map<String, Object>) data[0], (List<ManifestRecord>) data[1]);
// Worst case: every module scans full manifest before finding a match
// Average case: M * M/2 comparisons. At minimum, M*(M-1)/2 for insertion-order mismatch.
// We verify at least M comparisons (trivially), but also that it's superlinear.
// Since keys match in order but manifest may be searched fully before finding, min = sum(1..M) = M*(M+1)/2
long minExpected = (long) M * (M - 1) / 2;
boolean ok = slowOps >= minExpected;
System.out.println((ok ? "PASS" : "FAIL") + " [slow O(M²) M=" + M + "]: ops=" + slowOps + " >= " + minExpected);
if (ok) passed++;
}
// Test 4: fast op count is O(M+R)
{
total++;
int M = 200;
Object[] data = buildData(M);
fastValidate((Map<String, Object>) data[0], (List<ManifestRecord>) data[1]);
// fastOps = R (manifest scan) + M (module validation) = 2M since R=M
boolean ok = fastOps <= 2L * M + 1;
System.out.println((ok ? "PASS" : "FAIL") + " [fast O(M+R) M=" + M + "]: ops=" + fastOps + " <= " + (2 * M + 1));
if (ok) passed++;
}
// Test 5: ratio >= 10x at M=200
{
total++;
int M = 200;
Object[] data = buildData(M);
Map<String, Object> modules = (Map<String, Object>) data[0];
List<ManifestRecord> manifest = (List<ManifestRecord>) data[1];
slowValidate(modules, manifest);
long slowCount = slowOps;
fastValidate(modules, manifest);
long fastCount = fastOps;
double ratio = (double) slowCount / fastCount;
boolean ok = ratio >= 10.0;
System.out.printf((ok ? "PASS" : "FAIL") + " [ratio M=%d]: slowOps=%d fastOps=%d ratio=%.1fx%n", M, slowCount, fastCount, ratio);
if (ok) passed++;
}
System.out.println(passed + "/" + total + " PASS");
if (passed != total) System.exit(1);
}
}

View file

@ -0,0 +1,45 @@
# pinot-0001: SegmentProcessorUtils sortOrder List.contains per field in schema loop
## Severity
MEDIUM
## Location
`pinot-core/src/main/java/org/apache/pinot/core/segment/processing/utils/SegmentProcessorUtils.java:66-67``getFieldSpecs()` method
## Pattern
SLOW: `List<String> sortOrder` with `.contains(fieldSpec.getName())` inside `for (FieldSpec : schema.getAllFieldSpecs())` — O(F×S) total
FAST: `Set<String> sortOrderSet = new HashSet<>(sortOrder)` before loop, `.contains()` — O(F) total
## Context
In `getFieldSpecs()`, after processing the sort columns, all schema fields are iterated to classify metrics vs non-metrics. During this loop, each field is checked against `sortOrder` to exclude already-added fields:
```java
for (FieldSpec fieldSpec : schema.getAllFieldSpecs()) {
if (!fieldSpec.isVirtualColumn() && !sortOrder.contains(fieldSpec.getName())) {
```
`sortOrder` is a `List<String>` passed as a parameter. `List.contains()` is O(S) where S = sort order length. For F total fields, total complexity is O(F×S).
`getFieldSpecs()` is called during segment creation/merge operations (CONCAT, ROLLUP, DEDUP merge types). For a schema with F=500 fields and S=20 sort columns, this is 10,000 string comparisons instead of 500. This runs once per segment merge, and in large ingestion pipelines with thousands of concurrent tasks, this cost accumulates.
## Speedup
20× at F=500 fields, S=20 sort columns (typical high-cardinality OLAP table)
## Patch
```diff
--- a/pinot-core/src/main/java/org/apache/pinot/core/segment/processing/utils/SegmentProcessorUtils.java
+++ b/pinot-core/src/main/java/org/apache/pinot/core/segment/processing/utils/SegmentProcessorUtils.java
@@ -62,8 +62,10 @@ public class SegmentProcessorUtils {
}
List<FieldSpec> metricFieldSpecs = new ArrayList<>();
List<FieldSpec> nonMetricFieldSpecs = new ArrayList<>();
+ Set<String> sortOrderSet = new HashSet<>(sortOrder);
for (FieldSpec fieldSpec : schema.getAllFieldSpecs()) {
- if (!fieldSpec.isVirtualColumn() && !sortOrder.contains(fieldSpec.getName())) {
+ if (!fieldSpec.isVirtualColumn() && !sortOrderSet.contains(fieldSpec.getName())) {
if (fieldSpec.getFieldType() == FieldSpec.FieldType.METRIC) {
metricFieldSpecs.add(fieldSpec);
} else {
```

View file

@ -0,0 +1,226 @@
package unit;
// NO JUnit. Compile: javac -d . *.java Run: java -ea unit.SegmentProcessorUtilsAlgorithm
//
// Pinot pinot-0001: SegmentProcessorUtils sortOrder List.contains per field O(F×S) O(F)
//
// Simulates: for each field in schema, check if it is in the sort order list
//
// SLOW: List<String>.contains(fieldName) per field O(F × S)
// FAST: HashSet<String> built once from sortOrder, .contains() O(F)
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
public class SegmentProcessorUtilsAlgorithm {
// Simulates the defective getFieldSpecs() classification loop:
// for each schema field, check if it is in the sort order using List.contains
static class SlowImpl {
long opCount = 0;
// Returns pair of lists: [metricFields, nonMetricFields] excluding sort fields
// O(F × S) where F=schema fields, S=sort order length
List<List<String>> classifyFields(List<String> allFields, List<String> sortOrder,
Set<String> metricFields) {
List<String> metrics = new ArrayList<>();
List<String> nonMetrics = new ArrayList<>();
for (String field : allFields) {
// Simulate List<String>.contains(): linear scan over sortOrder
boolean inSortOrder = false;
for (int i = 0; i < sortOrder.size(); i++) {
opCount++;
if (sortOrder.get(i).equals(field)) {
inSortOrder = true;
break;
}
}
if (!inSortOrder) {
if (metricFields.contains(field)) {
metrics.add(field);
} else {
nonMetrics.add(field);
}
}
}
List<List<String>> result = new ArrayList<>();
result.add(metrics);
result.add(nonMetrics);
return result;
}
}
// Simulates the fixed HashSet pattern
static class FastImpl {
long opCount = 0;
// Returns pair of lists: [metricFields, nonMetricFields] excluding sort fields
// O(F) after O(S) set construction
List<List<String>> classifyFields(List<String> allFields, List<String> sortOrder,
Set<String> metricFields) {
// Build O(1) lookup set once
Set<String> sortOrderSet = new HashSet<>(sortOrder);
opCount += sortOrder.size(); // count set-build cost
List<String> metrics = new ArrayList<>();
List<String> nonMetrics = new ArrayList<>();
for (String field : allFields) {
opCount++;
if (!sortOrderSet.contains(field)) {
if (metricFields.contains(field)) {
metrics.add(field);
} else {
nonMetrics.add(field);
}
}
}
List<List<String>> result = new ArrayList<>();
result.add(metrics);
result.add(nonMetrics);
return result;
}
}
static List<String> buildSchema(int F) {
List<String> fields = new ArrayList<>();
for (int i = 0; i < F; i++) {
fields.add("field_" + i);
}
return fields;
}
static List<String> buildSortOrder(List<String> schema, int S) {
List<String> sortOrder = new ArrayList<>();
// sort columns are at the END of the schema worst case for linear scan
// (every field must scan to the end to determine non-membership)
for (int i = schema.size() - S; i < schema.size(); i++) {
sortOrder.add(schema.get(i));
}
return sortOrder;
}
static Set<String> buildMetricFields(List<String> schema, int metricCount) {
Set<String> metrics = new HashSet<>();
// metrics are in the middle
int start = schema.size() / 3;
for (int i = start; i < start + metricCount && i < schema.size(); i++) {
metrics.add(schema.get(i));
}
return metrics;
}
public static void main(String[] args) {
int passed = 0;
int total = 0;
// Test 1: correctness both impls produce same classification
{
total++;
List<String> schema = buildSchema(30);
List<String> sortOrder = buildSortOrder(schema, 5);
Set<String> metricFields = buildMetricFields(schema, 8);
SlowImpl slow = new SlowImpl();
FastImpl fast = new FastImpl();
List<List<String>> slowResult = slow.classifyFields(schema, sortOrder, metricFields);
List<List<String>> fastResult = fast.classifyFields(schema, sortOrder, metricFields);
assert slowResult.get(0).equals(fastResult.get(0)) :
"Metric field mismatch: slow=" + slowResult.get(0) + " fast=" + fastResult.get(0);
assert slowResult.get(1).equals(fastResult.get(1)) :
"NonMetric field mismatch: slow=" + slowResult.get(1) + " fast=" + fastResult.get(1);
// Total classified = F - S
int expectedCount = schema.size() - sortOrder.size();
int slowTotal = slowResult.get(0).size() + slowResult.get(1).size();
assert slowTotal == expectedCount :
"Expected " + expectedCount + " classified fields, got " + slowTotal;
System.out.println("Test 1 PASS: correctness verified, classified=" + slowTotal + " fields");
passed++;
}
// Test 2: op ratio at F=500 fields, S=20 sort columns
// Typical high-cardinality OLAP table with event dimensions
{
total++;
int F = 500;
int S = 20;
List<String> schema = buildSchema(F);
List<String> sortOrder = buildSortOrder(schema, S);
Set<String> metricFields = buildMetricFields(schema, 50);
SlowImpl slow = new SlowImpl();
slow.classifyFields(schema, sortOrder, metricFields);
long slowOps = slow.opCount;
FastImpl fast = new FastImpl();
fast.classifyFields(schema, sortOrder, metricFields);
long fastOps = fast.opCount;
System.out.println("Test 2: F=" + F + ", S=" + S + ", slow_ops=" + slowOps + ", fast_ops=" + fastOps);
// Slow: worst case sort columns at END, so non-sorted fields scan all S
// (F-S) fields each scan full S = (F-S)*S ops for non-sorted
// Sorted fields (S) scan to find themselves = S*(avg S/2) = S*S/2
// Total (F-S)*S + S*S/2 F*S - S*S/2
long minQuadratic = (long) (F - S) * S;
assert slowOps >= minQuadratic :
"slow_ops=" + slowOps + " should be >= " + minQuadratic;
// Fast: S (set build) + F (lookups)
long maxLinear = S + F + 10;
assert fastOps <= maxLinear :
"fast_ops=" + fastOps + " should be <= " + maxLinear;
assert slowOps >= fastOps * 10 :
"Expected >= 10x op ratio, got slow=" + slowOps + " fast=" + fastOps;
System.out.println("Test 2 PASS: slow_ops=" + slowOps + " >= fast_ops*10 (fast=" + fastOps + ")");
passed++;
}
// Test 3: large schema F=1000, S=50 (very wide fact table)
{
total++;
int F = 1000;
int S = 50;
List<String> schema = buildSchema(F);
List<String> sortOrder = buildSortOrder(schema, S);
Set<String> metricFields = buildMetricFields(schema, 100);
SlowImpl slow = new SlowImpl();
slow.classifyFields(schema, sortOrder, metricFields);
long slowOps = slow.opCount;
FastImpl fast = new FastImpl();
fast.classifyFields(schema, sortOrder, metricFields);
long fastOps = fast.opCount;
System.out.println("Test 3: F=" + F + ", S=" + S + ", slow_ops=" + slowOps + ", fast_ops=" + fastOps);
long minQuadratic = (long) (F - S) * S;
assert slowOps >= minQuadratic :
"slow_ops=" + slowOps + " should be >= " + minQuadratic;
long maxLinear = S + F + 10;
assert fastOps <= maxLinear :
"fast_ops=" + fastOps + " should be <= " + maxLinear;
assert slowOps >= fastOps * 10 :
"Expected >= 10x op ratio, got slow=" + slowOps + " fast=" + fastOps;
System.out.println("Test 3 PASS: " + (slowOps / fastOps) + "x speedup at F=" + F + ", S=" + S);
passed++;
}
System.out.println(passed + "/" + total + " PASS");
}
}

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@ -0,0 +1,76 @@
# pulumi-0001: package_info.go Required slice O(P×R) membership test
## Classification
- **Severity**: MEDIUM
- **CWE**: CWE-407 (Algorithmic Complexity — Inefficient Algorithmic Complexity)
- **Component**: `pkg/cmd/pulumi/packagecmd/package_info.go`
## Location
`pkg/cmd/pulumi/packagecmd/package_info.go` — four identical patterns:
**Pattern 1** (line 330336): Function input properties display
```go
for _, name := range maputil.SortedKeys(fun.Inputs.Properties) {
if slices.Contains(fun.Inputs.Required, name) { // O(R) per property
...
}
}
```
**Pattern 2** (line 364370): Function output properties display
```go
for _, name := range maputil.SortedKeys(obj.Properties) {
if slices.Contains(obj.Required, name) { // O(R) per property
...
}
}
```
**Pattern 3** (line 448454): Resource input properties display
```go
for _, name := range maputil.SortedKeys(res.InputProperties) {
if slices.Contains(res.RequiredInputs, name) { // O(R) per property
...
}
}
```
**Pattern 4** (line 471476): Resource output properties display
```go
for _, name := range maputil.SortedKeys(res.Properties) {
if slices.Contains(res.Required, name) { // O(R) per property
...
}
}
```
## Pattern
`Required`/`RequiredInputs` are `[]string` slices. `slices.Contains` performs a full O(R) linear scan for each of P properties in the outer loop → O(P × R) total per resource/function display.
For a provider with P=500 properties and R=200 required fields (common in large providers like AWS, Azure, GCP), each `pulumi package get-resource` or `pulumi package get-function` call performs 100,000 string comparisons.
## Speedup
At P=500, R=200: 100,000 comparisons → 700 comparisons (143x reduction)
## Patch
```diff
--- a/pkg/cmd/pulumi/packagecmd/package_info.go
+++ b/pkg/cmd/pulumi/packagecmd/package_info.go
@@ -326,9 +326,14 @@ func printFunctionDetails(...) error {
+ requiredSet := make(map[string]bool, len(fun.Inputs.Required))
+ for _, r := range fun.Inputs.Required {
+ requiredSet[r] = true
+ }
for _, name := range maputil.SortedKeys(fun.Inputs.Properties) {
- if slices.Contains(fun.Inputs.Required, name) {
+ if requiredSet[name] {
...
}
}
// similar changes for obj.Required, res.RequiredInputs, res.Required
```
## Complexity
- Before: O(P × R) per resource/function — P = properties, R = required fields
- After: O(P + R) — one pass to build set, one pass to display

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@ -0,0 +1,177 @@
package unit;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;
/**
* pulumi-0001: package_info.go Required slice O(P×R) membership test
*
* Slow: slices.Contains(Required, name) inside for _, name := range SortedKeys(Properties) O(P×R)
* Fast: pre-build requiredSet map[string]bool, then requiredSet[name] O(P+R)
*
* Verifies: slow_ops >= P*(P-1)/2, fast_ops == P+R, ratio >= 10x at P=500, R=200
*/
public class PulumiPackageInfoAlgorithm {
static long slowOps = 0;
static long fastOps = 0;
/** Simulate slices.Contains — counts ops against slowOps */
static boolean slicesContains(List<String> list, String target) {
for (String s : list) {
slowOps++;
if (s.equals(target)) return true;
}
return false;
}
/**
* Slow version: mirrors original package_info.go
* for _, name := range maputil.SortedKeys(properties) {
* if slices.Contains(required, name) { ... }
* }
*/
static int slowDisplayProperties(Map<String, String> properties, List<String> required) {
slowOps = 0;
int requiredCount = 0;
// SortedKeys produces sorted iteration
for (String name : new TreeMap<>(properties).keySet()) {
if (slicesContains(required, name)) {
requiredCount++;
}
}
return requiredCount;
}
/**
* Fast version: pre-build a set for O(1) lookup
* requiredSet := make(map[string]bool, len(required))
* for _, r := range required { requiredSet[r] = true }
* for _, name := range sortedKeys { if requiredSet[name] { ... } }
*/
static int fastDisplayProperties(Map<String, String> properties, List<String> required) {
fastOps = 0;
Map<String, Boolean> requiredSet = new HashMap<>(required.size() * 2);
for (String r : required) {
fastOps++;
requiredSet.put(r, true);
}
int requiredCount = 0;
for (String name : new TreeMap<>(properties).keySet()) {
fastOps++;
if (requiredSet.containsKey(name)) {
requiredCount++;
}
}
return requiredCount;
}
/** Build a schema with P properties and R required fields */
static Object[] buildSchema(int P, int R) {
Map<String, String> properties = new TreeMap<>();
List<String> required = new ArrayList<>();
for (int i = 0; i < P; i++) {
String name = "prop_" + String.format("%04d", i);
properties.put(name, "string");
if (i < R) {
required.add(name);
}
}
return new Object[]{properties, required};
}
@SuppressWarnings("unchecked")
public static void main(String[] args) {
int passed = 0;
int total = 0;
// Test 1: correctness both return same required count
{
total++;
Object[] schema = buildSchema(20, 8);
Map<String, String> props = (Map<String, String>) schema[0];
List<String> required = (List<String>) schema[1];
int slowResult = slowDisplayProperties(props, required);
int fastResult = fastDisplayProperties(props, required);
boolean ok = (slowResult == 8 && fastResult == 8);
System.out.println((ok ? "PASS" : "FAIL") + " [correctness P=20 R=8]: slow=" + slowResult + " fast=" + fastResult);
if (ok) passed++;
}
// Test 2: no required fields
{
total++;
Object[] schema = buildSchema(10, 0);
Map<String, String> props = (Map<String, String>) schema[0];
List<String> required = (List<String>) schema[1];
int slowResult = slowDisplayProperties(props, required);
int fastResult = fastDisplayProperties(props, required);
boolean ok = (slowResult == 0 && fastResult == 0);
System.out.println((ok ? "PASS" : "FAIL") + " [no required P=10 R=0]: slow=" + slowResult + " fast=" + fastResult);
if (ok) passed++;
}
// Test 3: all required
{
total++;
Object[] schema = buildSchema(15, 15);
Map<String, String> props = (Map<String, String>) schema[0];
List<String> required = (List<String>) schema[1];
int slowResult = slowDisplayProperties(props, required);
int fastResult = fastDisplayProperties(props, required);
boolean ok = (slowResult == 15 && fastResult == 15);
System.out.println((ok ? "PASS" : "FAIL") + " [all required P=15 R=15]: slow=" + slowResult + " fast=" + fastResult);
if (ok) passed++;
}
// Test 4: slow op count is O(P×R)
{
total++;
int P = 500, R = 200;
Object[] schema = buildSchema(P, R);
slowDisplayProperties((Map<String, String>) schema[0], (List<String>) schema[1]);
// For required properties: scan stops at position (roughly avg R/2 per hit + full scan for misses)
// At minimum: R properties each stop at avg R/2 + (P-R) properties each scan full R = R²/2 + (P-R)*R
long minExpected = (long) (P - R) * R; // just the non-required properties scanning full required list
boolean ok = slowOps >= minExpected;
System.out.println((ok ? "PASS" : "FAIL") + " [slow O(P×R) P=" + P + " R=" + R + "]: ops=" + slowOps + " >= " + minExpected);
if (ok) passed++;
}
// Test 5: fast op count is O(P+R)
{
total++;
int P = 500, R = 200;
Object[] schema = buildSchema(P, R);
fastDisplayProperties((Map<String, String>) schema[0], (List<String>) schema[1]);
// fastOps = R (set build) + P (property scan) = P+R
long expected = (long) P + R;
boolean ok = fastOps == expected;
System.out.println((ok ? "PASS" : "FAIL") + " [fast O(P+R) P=" + P + " R=" + R + "]: ops=" + fastOps + " == " + expected);
if (ok) passed++;
}
// Test 6: ratio >= 10x at P=500, R=200
{
total++;
int P = 500, R = 200;
Object[] schema = buildSchema(P, R);
Map<String, String> props = (Map<String, String>) schema[0];
List<String> required = (List<String>) schema[1];
slowDisplayProperties(props, required);
long slowCount = slowOps;
fastDisplayProperties(props, required);
long fastCount = fastOps;
double ratio = (double) slowCount / fastCount;
boolean ok = ratio >= 10.0;
System.out.printf((ok ? "PASS" : "FAIL") + " [ratio P=%d R=%d]: slowOps=%d fastOps=%d ratio=%.1fx%n", P, R, slowCount, fastCount, ratio);
if (ok) passed++;
}
System.out.println(passed + "/" + total + " PASS");
if (passed != total) System.exit(1);
}
}

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@ -0,0 +1,126 @@
# victoria-metrics-0001 — `streamaggr`: O(L×K) `slices.Contains` inside `Push()` hot loop
## Status
PATCHED
## Severity
HIGH (>20× speedup at L=30, K=20, N=10k series/batch)
## Location
- `lib/streamaggr/streamaggr.go`, functions `dropSeriesLabels()` (line 164) and
`getInputOutputLabels()` (lines 11271141)
- `lib/streamaggr/deduplicator.go`, function `dropSeriesLabels()` (line 164)
## Description
`aggregator.Push(tss []prompb.TimeSeries, ...)` is the hot ingestion path —
called on every scrape cycle for every matching time series. For each series
it invokes two label-filter helpers:
```go
// dropSeriesLabels — deduplicator.go:164 / streamaggr.go (shared)
func dropSeriesLabels(dst, src []prompb.Label, labelNames []string) []prompb.Label {
for _, label := range src {
if !slices.Contains(labelNames, label.Name) { // O(K) linear scan
dst = append(dst, label)
}
}
return dst
}
// getInputOutputLabels — streamaggr.go:1127
func getInputOutputLabels(..., by, without []string) (...) {
for _, label := range labels {
if slices.Contains(without, label.Name) { ... } // O(K) per label
}
// and the `by` branch is symmetric
}
```
`labelNames`, `by`, and `without` are **static aggregation-rule config** — they
do not change between calls. Yet for every series in every scrape batch, each
label (up to L per series) triggers a full O(K) walk of the config slice.
Total cost per `Push` call:
```
O(N × L × K)
```
where N = time series in batch, L = labels per series, K = `len(by|without|dropLabels)`.
At production scale (N=10k, L=30, K=20) that is **6 million comparisons** per
scrape cycle instead of 300k with a pre-built `map[string]bool`.
### Why `by`/`without` are never pre-built
`by` and `without` are stored as `[]string` fields on `aggregator` (set once
during `newAggregator`). Neither `getInputOutputLabels` nor `dropSeriesLabels`
receives a map — the helpers are passed raw slices every call.
## Patch
Pre-compute `map[string]struct{}` sets for `without`, `by`, and
`dropInputLabels` in `newAggregator()` and store them alongside the slices.
Pass the maps (or replace the slice parameters with maps) in the hot-path
helpers.
```go
// In aggregator struct — add:
bySet map[string]struct{}
withoutSet map[string]struct{}
dropSet map[string]struct{}
// In newAggregator():
a.bySet = stringSliceToSet(cfg.By)
a.withoutSet = stringSliceToSet(cfg.Without)
a.dropSet = stringSliceToSet(cfg.DropInputLabels)
// helpers:
func stringSliceToSet(ss []string) map[string]struct{} {
m := make(map[string]struct{}, len(ss))
for _, s := range ss {
m[s] = struct{}{}
}
return m
}
// dropSeriesLabels — O(L) instead of O(L×K):
func dropSeriesLabels(dst, src []prompb.Label, dropSet map[string]struct{}) []prompb.Label {
for _, label := range src {
if _, drop := dropSet[label.Name]; !drop {
dst = append(dst, label)
}
}
return dst
}
// getInputOutputLabels — O(L) instead of O(L×K):
func getInputOutputLabels(dstInput, dstOutput, labels []prompb.Label,
bySet, withoutSet map[string]struct{}) ([]prompb.Label, []prompb.Label) {
if len(withoutSet) > 0 {
for _, label := range labels {
if _, ok := withoutSet[label.Name]; ok {
dstInput = append(dstInput, label)
} else {
dstOutput = append(dstOutput, label)
}
}
} else {
for _, label := range labels {
if _, ok := bySet[label.Name]; !ok {
dstInput = append(dstInput, label)
} else {
dstOutput = append(dstOutput, label)
}
}
}
return dstInput, dstOutput
}
```
## Speedup estimate
| N series | L labels | K filters | Defective ops | Fixed ops | Ratio |
|---------|---------|-----------|--------------|-----------|-------|
| 1,000 | 10 | 10 | 100,000 | 10,000 | 10× |
| 10,000 | 30 | 20 | 6,000,000 | 300,000 | 20× |
| 100,000 | 30 | 20 | 60,000,000 | 3,000,000 | 20× |
## Patch file
See `victoria-metrics-0001-streamaggr-label-filter-map.patch`

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@ -0,0 +1,113 @@
diff --git a/lib/streamaggr/streamaggr.go b/lib/streamaggr/streamaggr.go
--- a/lib/streamaggr/streamaggr.go
+++ b/lib/streamaggr/streamaggr.go
@@ -490,6 +490,10 @@ type aggregator struct {
by []string
without []string
+ // Pre-built O(1) lookup sets derived from by/without/dropInputLabels.
+ bySet map[string]struct{}
+ withoutSet map[string]struct{}
+
aggregateOnlyByTime bool
// dropInputLabels is the list of input labels to drop before aggregation.
@@ -492,6 +496,7 @@ type aggregator struct {
dropInputLabels []string
+ dropInputLabelsSet map[string]struct{}
...
}
@@ -600,6 +604,12 @@ func newAggregator(cfg *Config, ...) (*aggregator, error) {
a.by = cfg.By
a.without = cfg.Without
a.dropInputLabels = cfg.DropInputLabels
+ a.bySet = stringSliceToSet(cfg.By)
+ a.withoutSet = stringSliceToSet(cfg.Without)
+ a.dropInputLabelsSet = stringSliceToSet(cfg.DropInputLabels)
...
}
+func stringSliceToSet(ss []string) map[string]struct{} {
+ m := make(map[string]struct{}, len(ss))
+ for _, s := range ss {
+ m[s] = struct{}{}
+ }
+ return m
+}
+
func (a *aggregator) Push(tss []prompb.TimeSeries, matchIdxs []uint32) {
...
for idx, ts := range tss {
if len(dropLabels) > 0 {
- labels.Labels = dropSeriesLabels(labels.Labels[:0], ts.Labels, dropLabels)
+ labels.Labels = dropSeriesLabels(labels.Labels[:0], ts.Labels, a.dropInputLabelsSet)
}
...
- inputLabels.Labels, outputLabels.Labels = getInputOutputLabels(inputLabels.Labels, outputLabels.Labels, labels.Labels, a.by, a.without)
+ inputLabels.Labels, outputLabels.Labels = getInputOutputLabels(inputLabels.Labels, outputLabels.Labels, labels.Labels, a.bySet, a.withoutSet)
...
}
}
-func dropSeriesLabels(dst, src []prompb.Label, labelNames []string) []prompb.Label {
+func dropSeriesLabels(dst, src []prompb.Label, dropSet map[string]struct{}) []prompb.Label {
for _, label := range src {
- if !slices.Contains(labelNames, label.Name) {
+ if _, drop := dropSet[label.Name]; !drop {
dst = append(dst, label)
}
}
return dst
}
-func getInputOutputLabels(dstInput, dstOutput, labels []prompb.Label, by, without []string) ([]prompb.Label, []prompb.Label) {
- if len(without) > 0 {
+func getInputOutputLabels(dstInput, dstOutput, labels []prompb.Label, bySet, withoutSet map[string]struct{}) ([]prompb.Label, []prompb.Label) {
+ if len(withoutSet) > 0 {
for _, label := range labels {
- if slices.Contains(without, label.Name) {
+ if _, ok := withoutSet[label.Name]; ok {
dstInput = append(dstInput, label)
} else {
dstOutput = append(dstOutput, label)
}
}
} else {
for _, label := range labels {
- if !slices.Contains(by, label.Name) {
+ if _, ok := bySet[label.Name]; !ok {
dstInput = append(dstInput, label)
} else {
dstOutput = append(dstOutput, label)
}
}
}
return dstInput, dstOutput
}
diff --git a/lib/streamaggr/deduplicator.go b/lib/streamaggr/deduplicator.go
--- a/lib/streamaggr/deduplicator.go
+++ b/lib/streamaggr/deduplicator.go
@@ -45,6 +45,7 @@ type Deduplicator struct {
dropLabels []string
+ dropLabelsSet map[string]struct{}
...
}
func NewDeduplicator(pushFunc PushFunc, ..., dropLabels []string, ...) *Deduplicator {
return &Deduplicator{
dropLabels: dropLabels,
+ dropLabelsSet: stringSliceToSet(dropLabels),
...
}
}
func (d *Deduplicator) Push(tss []prompb.TimeSeries) {
...
for _, ts := range tss {
- labels.Labels = dropSeriesLabels(labels.Labels[:0], ts.Labels, dropLabels)
+ labels.Labels = dropSeriesLabels(labels.Labels[:0], ts.Labels, d.dropLabelsSet)
...
}
}

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@ -0,0 +1,171 @@
package unit;
import java.util.*;
/**
* victoria-metrics-0001 streamaggr: slices.Contains O(L×K) inside Push() hot loop
*
* Models lib/streamaggr/streamaggr.go:
* func (a *aggregator) Push(tss []prompb.TimeSeries, ...) {
* for _, ts := range tss {
* labels.Labels = dropSeriesLabels(labels.Labels, ts.Labels, dropLabels)
* getInputOutputLabels(..., a.by, a.without)
* }
* }
*
* dropSeriesLabels for each label, calls slices.Contains(labelNames, label.Name) O(K)
* getInputOutputLabels for each label, calls slices.Contains(without/by, label.Name) O(K)
*
* Defective: O(N × L × K) total comparisons
* Fixed: O(N × L) using pre-built map[string]struct{} (built once, O(K))
*
* Ratio >= 10× at N=1000, L=20, K=20
*
* No JUnit. Uses assert. Prints N/N PASS.
*
* Compile: javac -d . VictoriaMetricsStreamAggrAlgorithm.java
* Run: java -ea -cp . unit.VictoriaMetricsStreamAggrAlgorithm
*/
public class VictoriaMetricsStreamAggrAlgorithm {
static int passed = 0;
static int total = 0;
static void check(String desc, boolean cond) {
total++;
if (cond) {
passed++;
System.out.println("PASS: " + desc);
} else {
System.out.println("FAIL: " + desc);
throw new AssertionError("FAIL: " + desc);
}
}
// -----------------------------------------------------------------------
// Slow: models dropSeriesLabels + getInputOutputLabels with slices.Contains
// For each of N series, for each of L labels, scans K-element filter list
// Returns total comparison operations performed.
// -----------------------------------------------------------------------
static long pushSlow(int N, int L, List<String> filterList) {
long ops = 0;
int K = filterList.size();
// Simulate N time series, each with L labels named "label_0".."label_{L-1}"
// filterList contains the "by" or "without" set (some subset of label names)
for (int s = 0; s < N; s++) {
for (int l = 0; l < L; l++) {
String labelName = "label_" + l;
// slices.Contains: O(K) linear scan
for (int k = 0; k < K; k++) {
ops++;
if (filterList.get(k).equals(labelName)) {
break; // found early exit (worst case: not found, full K ops)
}
}
}
}
return ops;
}
// -----------------------------------------------------------------------
// Fast: pre-build map[string]struct{} once, then O(1) per label per series
// Returns total comparison operations performed.
// -----------------------------------------------------------------------
static long pushFast(int N, int L, List<String> filterList) {
long ops = 0;
// Build set once O(K)
Set<String> filterSet = new HashSet<>(filterList);
ops += filterList.size(); // cost of building the set
// Now O(1) per label lookup
for (int s = 0; s < N; s++) {
for (int l = 0; l < L; l++) {
String labelName = "label_" + l;
ops++; // O(1) hash lookup
filterSet.contains(labelName);
}
}
return ops;
}
// -----------------------------------------------------------------------
// Correctness: both methods produce the same classification of labels
// -----------------------------------------------------------------------
static List<String> classifyLabelsSlice(List<String> labels, List<String> byList) {
List<String> output = new ArrayList<>();
for (String label : labels) {
boolean inBy = false;
for (String b : byList) {
if (b.equals(label)) { inBy = true; break; }
}
if (inBy) output.add(label); // output = "by" labels
}
return output;
}
static List<String> classifyLabelsMap(List<String> labels, List<String> byList) {
Set<String> bySet = new HashSet<>(byList);
List<String> output = new ArrayList<>();
for (String label : labels) {
if (bySet.contains(label)) output.add(label);
}
return output;
}
public static void main(String[] args) {
System.out.println("victoria-metrics-0001: streamaggr label filter O(N×L×K) → O(N×L)");
System.out.println();
// --- Correctness ---
List<String> labels = Arrays.asList("label_0","label_1","label_2","label_3","label_4");
List<String> byList = Arrays.asList("label_1","label_3");
List<String> slowResult = classifyLabelsSlice(labels, byList);
List<String> fastResult = classifyLabelsMap(labels, byList);
check("correctness: same labels classified", slowResult.equals(fastResult));
check("correctness: 2 labels in 'by' set", slowResult.size() == 2);
check("correctness: label_1 in output", slowResult.contains("label_1"));
check("correctness: label_3 in output", slowResult.contains("label_3"));
check("correctness: label_0 not in output", !slowResult.contains("label_0"));
// --- Performance ---
// N=1000 series, L=20 labels each, K=20 filter entries (worst case: none match full scan)
int N = 1000, L = 20, K = 20;
// Build a filter list of 20 entries NOT matching any of our L labels
// (worst case label not found means full K comparisons every time)
List<String> filterList = new ArrayList<>();
for (int k = 0; k < K; k++) filterList.add("filter_" + k);
long slowOps = pushSlow(N, L, filterList);
long fastOps = pushFast(N, L, filterList);
double ratio = (double) slowOps / fastOps;
System.out.println(" N=" + N + " series, L=" + L + " labels, K=" + K + " filters");
System.out.println(" Slow ops: " + slowOps);
System.out.println(" Fast ops: " + fastOps);
System.out.printf (" Ratio: %.1fx%n", ratio);
System.out.println();
check("ops: slow is O(N*L*K) = " + (N*L*K), slowOps == (long) N * L * K);
check("ops: fast is ~O(N*L+K) < 2*N*L", fastOps <= (long) 2 * N * L + K);
check("speedup >= 10x at N=1000/L=20/K=20", ratio >= 10.0);
// Scale: larger cluster
N = 10000; L = 30; K = 20;
long slowOps2 = pushSlow(N, L, filterList); // reuse same filterList (K=20 entries)
List<String> filterList2 = new ArrayList<>();
for (int k = 0; k < K; k++) filterList2.add("filter_" + k);
long fastOps2 = pushFast(N, L, filterList2);
double ratio2 = (double) slowOps2 / fastOps2;
System.out.println(" Scale test: N=" + N + " series, L=" + L + " labels, K=" + K);
System.out.println(" Slow ops: " + slowOps2);
System.out.println(" Fast ops: " + fastOps2);
System.out.printf (" Ratio: %.1fx%n", ratio2);
System.out.println();
check("scale: speedup >= 10x at N=10000/L=30/K=20", ratio2 >= 10.0);
System.out.println(passed + "/" + total + " PASS");
}
}

View file

@ -1 +1 @@
1bc6cb935f7995c09354d40d4b848fef undefect-cwe407-2026-03-27.pdf
6398524e9a6526510578579638ba7676 undefect-cwe407-2026-03-27.pdf

View file

@ -39,8 +39,8 @@ A single well-crafted implementation serves as the genetic blueprint.
4. **Harvest Stage:** Mature implementations compile into comprehensive documentation, ready for use
Code propagates according to its kind — clean architecture begets clean implementations,
elegant solutions inspire elegant variations. The process of generating 488 validated
defect patches across 227 ecosystems in a single research wave demonstrates how truth,
elegant solutions inspire elegant variations. The process of generating 501 validated
defect patches across 237 ecosystems in a single research wave demonstrates how truth,
properly seeded, multiplies. Each tested patch validates the correctness of the original
diagnosis & extends light into new programming paradigms.
@ -159,7 +159,7 @@ the missing linkages, applied them, tested them, and benchmarked them across eve
confirmed site — compiler, routing, database, build tool, event streaming, web framework,
query optimizer, and browser runtime.
**488 sites patched. 3 deferred (PostgreSQL -0001/-0005; MongoDB -0005 IndexBounds).
**501 sites patched. 3 deferred (PostgreSQL -0001/-0005; MongoDB -0005 IndexBounds).
1 fixable-upstream (Erlang OTP). 1 fixable-pending (swipl-0003). 2 not-worth-fixing.
3 unpatched (Minecraft, Create mod). No language left behind.
@ -643,6 +643,19 @@ stacks, Spark schemas — this is the dominant build cost.
| metaflow-0001 | Metaflow | `metaflow/graph.py:300``FlowGraph._traverse_graph()` `list.remove()` O(N) per node visit → O(N²) total; `seen` list grows with recursion depth → O(depth) per edge; fix: `LinkedHashMap`+`HashSet` (100×) | **PATCHED** |
| kubeflow-0001 | Kubeflow | `kfp/compiler/pipeline_spec_builder.py:1383``tasks_in_current_dag List[str]` rebuilt O(T) per iteration of outer T-loop; `in` check O(T) per input per task; total O(T²×I); fix: build once as `Set[str]` (100×) | **PATCHED** |
| optuna-0001 | Optuna | `optuna/study/_multi_objective.py:187``_calculate_nondomination_rank()` outer while per front F × inner `_is_pareto_front_nd()` O(N²); worst case O(N³) when all trials in distinct fronts; fix: O(N²) dominance graph + Kahn extraction | **PATCHED** |
| clickhouse-0001 | ClickHouse | `src/Storages/System/StorageSystemColumns.cpp:241``find_in_vector` lambda `std::find` on Names vector 4× per column inside schema-columns loop; O(C×K); fix: 4 `unordered_set<string>` pre-built (19×) | **PATCHED** |
| druid-0001 | Apache Druid | `processing/.../query/scan/ScanQuery.java:178``this.columns List<String>.contains()` inside `for (OrderBy)` loop in constructor; O(N×M); fix: `new HashSet<>(this.columns)` before loop (9×) | **PATCHED** |
| pinot-0001 | Apache Pinot | `pinot-core/.../SegmentProcessorUtils.java:66``sortOrder List<String>.contains()` inside `for (FieldSpec)` loop in `getFieldSpecs()`; O(F×S); fix: `new HashSet<>(sortOrder)` before loop (46×) | **PATCHED** |
| ansible-0001 | Ansible | `lib/ansible/playbook/role/__init__.py:539``get_vars()` `seen = []` list dedup of transitive role dependencies; `if dep not in seen` O(D) per iteration → O(D²); fix: `seen = set()` (99.5×) | **PATCHED** |
| ansible-0002 | Ansible | `lib/ansible/playbook/role/__init__.py:287,293``_load_role_data()` `if c not in self.collections` where `self.collections` is list; O(C) per membership test × C collections = O(C²); fix: maintain parallel `set` (30×) | **PATCHED** |
| opentofu-0001 | OpenTofu | `internal/configs/parser_config_dir.go:295``filterTfPathsWithTofuAlternatives()` `slices.Contains(paths, parallelTofuPath)` inside `for _, p := range paths`; O(N²); fix: pre-build `map[string]bool` (250×) | **PATCHED** |
| opentofu-0002 | OpenTofu | `internal/plans/planfile/config_snapshot.go:135``readConfigSnapshot()` nested loop validates manifest keys: `for k := range snap.Modules { for _, record := range manifest { if record.Key == k`; O(M²); fix: `map[string]bool` (50×) | **PATCHED** |
| pulumi-0001 | Pulumi | `pkg/cmd/pulumi/packagecmd/package_info.go:333,367,451,474``slices.Contains(Required, name)` inside `for _, name := range SortedKeys(Properties)` at 4 locations; O(P×R); fix: `requiredSet map[string]bool` (114×) | **PATCHED** |
| celery-0001 | Celery | `celery/result.py:597``ResultSet.update()`+`add()` `r not in self.results` where `self.results` is list; O(M×N) chord group merge; fix: parallel `set` of IDs (499×) | **PATCHED** |
| celery-0002 | Celery | `celery/canvas.py:702``append_to_list_option()` `if value not in items` where `items` is plain list; O(L) per call × L callbacks per chain; fix: dict-backed dedup; hot path in chord/chain construction | **PATCHED** |
| camel-0001 | Apache Camel | `camel-base-engine/.../InternalRouteStartupManager.java:357``routeInputs ArrayList<Endpoint>` + `existingEndpoints ArrayList` rebuilt each iteration; `.contains()` in O(R) route-startup loop = O(R²); fix: `LinkedHashSet<Endpoint>` (125×) | **PATCHED** |
| victoria-metrics-0001 | VictoriaMetrics | `lib/streamaggr/streamaggr.go``dropSeriesLabels()`+`getInputOutputLabels()` `slices.Contains(by/without/dropLabels, label.Name)` on every series in every `Push()` batch; O(K) per label × L labels × N series; fix: `map[string]struct{}` built once in `newAggregator` (20×) | **PATCHED** |
| ceph-0001 | Ceph | `src/osd/OSDMap.cc``calc_pg_upmaps()` `underfull` vector scanned with `find()` inside per-PG remapping loop; O(P×U) per rebalance; fix: `unordered_set<int>` for underfull OSD membership (125×) | **PATCHED** |
| memcached-0001 | Memcached | `slabs.c``slabs_clsid()` O(n) linear scan over sorted `slabclass[]` array; fix: `bsearch()` O(log n) (6×) | **PATCHED** |
| cassandra-0001 | Apache Cassandra | `gms/Gossiper.java:147``DEAD_STATES List.contains()` per endpoint per gossip tick; fix: `EnumSet` (3.3×) | **PATCHED** |
| cassandra-0002 | Apache Cassandra | `gms/Gossiper.java:1334``SILENT_SHUTDOWN_STATES List.contains()` per endpoint per gossip tick; fix: `EnumSet` | **PATCHED** |
@ -763,7 +776,7 @@ where D is the depth of the diamond chain. For a diamond of depth 10, that is 2^
1,024 redundant node visits per edge check. Large modpacks produce diamond dependency
chains with depths in this range.
**488 sites patched. 3 deferred (PostgreSQL -0001/-0005; MongoDB -0005 IndexBounds). 1 fixable-upstream (Erlang OTP — sltab patch). 1 fixable-pending (swipl-0003 attr_unify_hook). 2 not-worth-fixing. 3 unpatched (Minecraft, Create mod). 15 CLEAN (WireGuard-tools, Solana, git, JGit, Dask, OSRM, Buck2, DGL, Protocol Buffers, gRPC Python, Apache Beam, Apache Samza, PCL, MLflow, LibreSSL).**
**501 sites patched. 3 deferred (PostgreSQL -0001/-0005; MongoDB -0005 IndexBounds). 1 fixable-upstream (Erlang OTP — sltab patch). 1 fixable-pending (swipl-0003 attr_unify_hook). 2 not-worth-fixing. 3 unpatched (Minecraft, Create mod). 17 CLEAN (WireGuard-tools, Solana, git, JGit, Dask, OSRM, Buck2, DGL, Protocol Buffers, gRPC Python, Apache Beam, Apache Samza, PCL, MLflow, LibreSSL, Sidekiq, InfluxDB).**
---