diff options
| author | Tom Lane | 2022-12-22 15:35:03 +0000 |
|---|---|---|
| committer | Tom Lane | 2022-12-22 15:35:03 +0000 |
| commit | 8cd700cc5a676282912c7080cfa142977a2dd851 (patch) | |
| tree | 9a904270f5bfee1bd066f0e3f75267c72f9e625c | |
| parent | 0ff4056b8ce994e2932260c9f194675769b3d2e5 (diff) | |
Add some recursion and looping defenses in prepjointree.c.
Andrey Lepikhov demonstrated a case where we spend an unreasonable
amount of time in pull_up_subqueries(). Not only is that recursing
with no explicit check for stack overrun, but the code seems not
interruptable by control-C. Let's stick a CHECK_FOR_INTERRUPTS
there, along with sprinkling some stack depth checks.
An actual fix for the excessive time consumption seems a bit
risky to back-patch; but this isn't, so let's do so.
Discussion: https://postgr.es/m/703c09a2-08f3-d2ec-b33d-dbecd62428b8@postgrespro.ru
| -rw-r--r-- | src/backend/optimizer/prep/prepjointree.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/src/backend/optimizer/prep/prepjointree.c b/src/backend/optimizer/prep/prepjointree.c index fe1149ee4bf..e3c62cb3481 100644 --- a/src/backend/optimizer/prep/prepjointree.c +++ b/src/backend/optimizer/prep/prepjointree.c @@ -24,6 +24,7 @@ #include "postgres.h" #include "catalog/pg_type.h" +#include "miscadmin.h" #include "nodes/makefuncs.h" #include "nodes/nodeFuncs.h" #include "optimizer/clauses.h" @@ -178,6 +179,9 @@ static Node * pull_up_sublinks_jointree_recurse(PlannerInfo *root, Node *jtnode, Relids *relids) { + /* Since this function recurses, it could be driven to stack overflow. */ + check_stack_depth(); + if (jtnode == NULL) { *relids = NULL; @@ -677,6 +681,11 @@ pull_up_subqueries_recurse(PlannerInfo *root, Node *jtnode, AppendRelInfo *containing_appendrel, bool deletion_ok) { + /* Since this function recurses, it could be driven to stack overflow. */ + check_stack_depth(); + /* Also, since it's a bit expensive, let's check for query cancel. */ + CHECK_FOR_INTERRUPTS(); + Assert(jtnode != NULL); if (IsA(jtnode, RangeTblRef)) { @@ -1824,6 +1833,9 @@ is_simple_union_all(Query *subquery) static bool is_simple_union_all_recurse(Node *setOp, Query *setOpQuery, List *colTypes) { + /* Since this function recurses, it could be driven to stack overflow. */ + check_stack_depth(); + if (IsA(setOp, RangeTblRef)) { RangeTblRef *rtr = (RangeTblRef *) setOp; |