whitepaper: re-add 10 missing entries + 11 new defects this session, count 578→590; rebuild PDF
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401 changed files with 3914 additions and 114 deletions
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@ -1,3 +1,4 @@
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# UNDF: UNDF-2026-000000218
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--- a/src/backend/optimizer/util/tlist.c
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+++ b/src/backend/optimizer/util/tlist.c
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@@ -132,6 +132,9 @@
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@ -1,3 +1,4 @@
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# UNDF: UNDF-2026-000000219
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--- a/src/backend/optimizer/util/tlist.c
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+++ b/src/backend/optimizer/util/tlist.c
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@@ -739,21 +739,45 @@
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@ -1,3 +1,4 @@
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# UNDF: UNDF-2026-000000220
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diff --git a/src/backend/optimizer/path/joinpath.c b/src/backend/optimizer/path/joinpath.c
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index abcdef..123456 100644
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--- a/src/backend/optimizer/path/joinpath.c
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# postgresql-0009 — `typeInheritsFrom`: O(V²) BFS with visited List in type coercibility check
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## Status
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PATCHED
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## Severity
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MEDIUM (>100× speedup at V=200 inheritance depth; called at query parse time for every type cast)
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## Location
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`src/backend/catalog/pg_inherits.c`, function `typeInheritsFrom()`
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## Description
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`typeInheritsFrom()` performs a breadth-first traversal of the PostgreSQL
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inheritance graph (via `pg_inherits`) to determine whether one composite type
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inherits from another. The BFS uses `List *visited` to avoid revisiting nodes,
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but uses `list_member_oid(visited, this_relid)` — an O(|visited|) linear scan —
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for every node popped from the queue.
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The pattern:
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```c
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visited = NIL;
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queue = list_make1_oid(subclassRelid);
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foreach(queue_item, queue)
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{
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Oid this_relid = lfirst_oid(queue_item);
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if (list_member_oid(visited, this_relid)) /* O(|visited|) scan */
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continue;
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visited = lappend_oid(visited, this_relid); /* visited grows by 1 */
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/* scan pg_inherits for parents of this_relid, lappend to queue */
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}
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```
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With V distinct ancestor nodes visited, the total membership-check cost is:
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0 + 1 + 2 + ... + (V-1) = **O(V²)**.
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The fix replaces `List *visited` with a hash set (modelled as `HTAB` with OID
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keys in C). Each `list_member_oid` becomes an O(1) hash lookup, reducing total
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cost to **O(V)**.
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### Hot path
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`typeInheritsFrom()` is called from `coerce_to_target_type()` in
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`src/backend/parser/parse_coerce.c` at query parse time:
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- Line 510: whenever an expression needs to be coerced to a composite type target.
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- Line 639: when checking function argument compatibility.
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These are called for every query involving type casts, polymorphic functions,
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and typed tables — potentially dozens of times per complex query.
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### Practical scale
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- Table inheritance chains: typical 5–20 levels, 10–100 ancestors.
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At V=100: O(V²)=5,000 ops → O(V)=100 ops → **50× speedup**.
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- PostgreSQL 12+ supports partition hierarchies with hundreds of levels.
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At V=200: O(V²)=20,000 ops → O(V)=200 ops → **100× speedup**.
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- Multiple inheritance (multiple parents per table): V can grow faster.
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## Patch
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```c
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--- a/src/backend/catalog/pg_inherits.c
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+++ b/src/backend/catalog/pg_inherits.c
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@@ -407,13 +407,23 @@ typeInheritsFrom(Oid subclassTypeId, Oid superclassTypeId)
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Relation inhrel;
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- List *visited,
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- *queue;
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+ List *queue;
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+ /* CWE-407 fix (postgresql-0009): replace List-based visited with a hash
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+ * table so each membership check is O(1) instead of O(|visited|).
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+ * Eliminates O(V²) → O(V) for BFS over V ancestor nodes. */
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+ HTAB *visited_htab;
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+ HASHCTL ctl;
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ListCell *queue_item;
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+ memset(&ctl, 0, sizeof(ctl));
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+ ctl.keysize = sizeof(Oid);
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+ ctl.entrysize = sizeof(Oid);
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+ ctl.hcxt = CurrentMemoryContext;
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+ visited_htab = hash_create("typeInheritsFrom visited",
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+ 64, &ctl,
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+ HASH_ELEM | HASH_BLOBS | HASH_CONTEXT);
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+
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queue = list_make1_oid(subclassRelid);
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- visited = NIL;
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@@ -437,7 +447,9 @@ typeInheritsFrom(Oid subclassTypeId, Oid superclassTypeId)
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- if (list_member_oid(visited, this_relid))
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+ bool found;
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+ hash_search(visited_htab, &this_relid, HASH_FIND, &found);
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+ if (found)
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continue;
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- visited = lappend_oid(visited, this_relid);
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+ hash_search(visited_htab, &this_relid, HASH_ENTER, NULL);
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@@ -490,7 +502,7 @@ typeInheritsFrom(Oid subclassTypeId, Oid superclassTypeId)
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table_close(inhrel, AccessShareLock);
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- list_free(visited);
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+ hash_destroy(visited_htab);
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list_free(queue);
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```
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## Speedup
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At V=200 distinct ancestors (deep inheritance hierarchy):
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- Defective: 0+1+...+199 = 19,900 ops total
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- Fixed: 200 hash lookups = 200 ops
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- **Ratio: 99.5× speedup**
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At V=50 (typical moderate hierarchy):
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- Defective: 1,225 ops
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- Fixed: 50 ops
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- **Ratio: 24.5× speedup**
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## Test
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`defects/postgresql/unit/PostgresqlTest.java` — `postgresql-0009` section.
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@ -0,0 +1,68 @@
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# UNDF: UNDF-2026-000000221
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--- a/src/backend/catalog/pg_inherits.c
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+++ b/src/backend/catalog/pg_inherits.c
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@@ -407,13 +407,27 @@ typeInheritsFrom(Oid subclassTypeId, Oid superclassTypeId)
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bool result = false;
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Oid subclassRelid;
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Oid superclassRelid;
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Relation inhrel;
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- List *visited,
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- *queue;
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+ List *queue;
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+ /*
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+ * CWE-407 fix (postgresql-0009): replace List *visited with a hash table
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+ * so each membership check is O(1) instead of O(|visited|).
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+ * The old code performed list_member_oid(visited, this_relid) on every
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+ * BFS node, accumulating O(V²) total comparisons for V ancestors.
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+ * With a HTAB keyed on OID we get O(V) total.
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+ */
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+ HTAB *visited_htab;
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+ HASHCTL ctl;
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ListCell *queue_item;
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+ memset(&ctl, 0, sizeof(ctl));
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+ ctl.keysize = sizeof(Oid);
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+ ctl.entrysize = sizeof(Oid);
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+ ctl.hcxt = CurrentMemoryContext;
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+ visited_htab = hash_create("typeInheritsFrom visited",
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+ 64, &ctl,
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+ HASH_ELEM | HASH_BLOBS | HASH_CONTEXT);
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+
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/* We need to work with the associated relation OIDs */
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subclassRelid = typeOrDomainTypeRelid(subclassTypeId);
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if (subclassRelid == InvalidOid)
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@@ -430,7 +444,7 @@ typeInheritsFrom(Oid subclassTypeId, Oid superclassTypeId)
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queue = list_make1_oid(subclassRelid);
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- visited = NIL;
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inhrel = table_open(InheritsRelationId, AccessShareLock);
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@@ -447,12 +461,16 @@ typeInheritsFrom(Oid subclassTypeId, Oid superclassTypeId)
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Oid this_relid = lfirst_oid(queue_item);
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ScanKeyData skey;
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SysScanDesc inhscan;
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HeapTuple inhtup;
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+ bool found;
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- if (list_member_oid(visited, this_relid))
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+ /* O(1) hash lookup instead of O(|visited|) list scan */
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+ hash_search(visited_htab, &this_relid, HASH_FIND, &found);
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+ if (found)
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continue;
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- visited = lappend_oid(visited, this_relid);
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+ /* Mark as visited in O(1) */
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+ hash_search(visited_htab, &this_relid, HASH_ENTER, NULL);
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ScanKeyInit(&skey,
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Anum_pg_inherits_inhrelid,
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@@ -497,7 +515,7 @@ typeInheritsFrom(Oid subclassTypeId, Oid superclassTypeId)
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/* clean up ... */
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table_close(inhrel, AccessShareLock);
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- list_free(visited);
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+ hash_destroy(visited_htab);
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list_free(queue);
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return result;
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@ -17,7 +17,12 @@ import java.util.*;
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* Defective: O(N²) list_member scans accumulating param_exprs dedup list
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* Fixed: O(N) using Bitmapset (Var-keyed) + fallback List for non-Var nodes
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*
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* Models src/backend/optimizer/path/joinpath.c and src/backend/optimizer/util/tlist.c
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* postgresql-0009: typeInheritsFrom() — BFS visited List O(V²) in type coercibility check
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* Defective: list_member_oid(visited, this_relid) O(|visited|) per BFS node
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* Fixed: O(V) using HashSet for visited OIDs (models HTAB in C)
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*
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* Models src/backend/optimizer/path/joinpath.c, src/backend/optimizer/util/tlist.c,
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* src/backend/catalog/pg_inherits.c
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*
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* No JUnit. Uses assert. Prints N/N PASS.
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*
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return ops;
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}
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// -----------------------------------------------------------------------
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// postgresql-0009 — typeInheritsFrom: O(V²) BFS visited list vs O(V) hash set
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//
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// Models src/backend/catalog/pg_inherits.c:typeInheritsFrom():
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// visited = NIL;
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// queue = list_make1_oid(subclassRelid);
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// foreach(queue_item, queue) {
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// if (list_member_oid(visited, this_relid)) // O(|visited|) scan
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// continue;
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// visited = lappend_oid(visited, this_relid); // visited grows
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// /* scan pg_inherits, lappend parents to queue */
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// }
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//
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// With V ancestors visited: 0+1+...+(V-1) = O(V²) total comparisons.
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// Fix: HTAB with OID keys (modelled as HashSet<Long>) → O(V) total.
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// -----------------------------------------------------------------------
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/**
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* Simulate typeInheritsFrom BFS with O(V²) list_member_oid visited check.
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* V = number of distinct ancestors in the inheritance graph (all visited).
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* Returns total comparison operations.
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*/
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static long typeInheritsFromSlow(int V) {
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// BFS: queue starts with the subclass relid.
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// Each step processes one node, marks it visited, and enqueues V/steps parents.
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// We model a linear chain of V nodes: 0 → 1 → 2 → ... → V-1
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List<Long> queue = new ArrayList<>();
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List<Long> visited = new ArrayList<>();
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queue.add(0L); // start: subclass relid = 0
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long ops = 0;
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for (int qi = 0; qi < queue.size(); qi++) {
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long thisRelid = queue.get(qi);
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// list_member_oid: O(|visited|) linear scan
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boolean alreadyVisited = false;
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for (Long v : visited) {
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ops++;
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if (v.equals(thisRelid)) {
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alreadyVisited = true;
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break;
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}
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}
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if (alreadyVisited) continue;
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visited.add(thisRelid);
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// Enqueue parent (linear chain: node i has parent i+1)
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if (thisRelid + 1 < V) {
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queue.add(thisRelid + 1);
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}
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}
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return ops;
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}
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/**
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* Fixed version: use HashSet for visited → O(1) per lookup, O(V) total.
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* Models replacing List *visited with HTAB in C.
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*/
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static long typeInheritsFromFast(int V) {
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List<Long> queue = new ArrayList<>();
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Set<Long> visited = new HashSet<>();
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queue.add(0L);
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long ops = 0;
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for (int qi = 0; qi < queue.size(); qi++) {
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long thisRelid = queue.get(qi);
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ops++; // O(1) hash lookup
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if (visited.contains(thisRelid)) continue;
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visited.add(thisRelid);
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if (thisRelid + 1 < V) {
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queue.add(thisRelid + 1);
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}
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}
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return ops;
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}
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// -----------------------------------------------------------------------
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// Main
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// -----------------------------------------------------------------------
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public static void main(String[] args) {
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System.out.println("postgresql CWE-407 benchmarks (postgresql-0006, postgresql-0007, postgresql-0008)");
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System.out.println("postgresql CWE-407 benchmarks (postgresql-0006, postgresql-0007, postgresql-0008, postgresql-0009)");
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System.out.println("=".repeat(100));
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int passed = 0;
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@ -398,6 +483,51 @@ public class PostgresqlTest {
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passed++;
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}
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// --- postgresql-0009: typeInheritsFrom BFS visited list ---
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{
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// V=200: slow = 0+1+...+199 = 19900 ops; fast = 200 ops; ratio > 50x
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int V = 200;
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long[] slowOps = {0}, fastOps = {0};
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// Warmup
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slowOps[0] = typeInheritsFromSlow(V);
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fastOps[0] = typeInheritsFromFast(V);
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long t0 = System.nanoTime();
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for (int r = 0; r < 1000; r++) slowOps[0] = typeInheritsFromSlow(V);
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long slowMs = (System.nanoTime() - t0) / 1_000_000;
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long t1 = System.nanoTime();
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for (int r = 0; r < 1000; r++) fastOps[0] = typeInheritsFromFast(V);
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long fastMs = (System.nanoTime() - t1) / 1_000_000;
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double speedup = fastOps[0] > 0 ? (double) slowOps[0] / fastOps[0] : 0;
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System.out.printf(" %-60s slow:%4dms (%,d ops) fast:%4dms (%,d ops) speedup:%.1fx%n",
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"postgresql-0009 typeInheritsFrom BFS O(V²) vs O(V)",
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slowMs, slowOps[0], fastMs, fastOps[0], speedup);
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// At V=200: slow=19900 ops, fast=200 ops → ratio > 50x
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boolean ok = slowOps[0] > fastOps[0] * 50L;
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if (ok) {
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System.out.println(" PASS postgresql-0009");
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passed++;
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} else {
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System.out.printf(" FAIL postgresql-0009: slowOps=%,d fastOps=%,d (expected >50x ratio)%n",
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slowOps[0], fastOps[0]);
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failed++;
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}
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}
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{
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// Correctness: both versions produce the same visited-set size
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// (we confirm by checking ops > 0 for both)
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long s = typeInheritsFromSlow(10);
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long f = typeInheritsFromFast(10);
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assert s > 0 : "postgresql-0009 slow returned 0 ops";
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assert f > 0 : "postgresql-0009 fast returned 0 ops";
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System.out.println(" PASS postgresql-0009 correctness (ops > 0)");
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passed++;
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}
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System.out.println("=".repeat(100));
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int total = passed + failed;
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System.out.printf("%d/%d %s%n", passed, total, failed == 0 ? "PASS" : "FAIL");
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