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Commitb26ed35

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Avoid deep recursion when assigning XIDs to multiple levels of subxacts.
Backpatch to 8.0.Andres Freund, with cleanup and adjustment for older branches by me.
1 parentb239670 commitb26ed35

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1 file changed

+29
-2
lines changed
  • src/backend/access/transam

1 file changed

+29
-2
lines changed

‎src/backend/access/transam/xact.c

Lines changed: 29 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -10,7 +10,7 @@
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.195.4.6 2010/01/24 21:50:06 tgl Exp $
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* $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.195.4.7 2010/07/23 00:43:52 rhaas Exp $
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*
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*-------------------------------------------------------------------------
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*/
@@ -339,8 +339,35 @@ AssignSubTransactionId(TransactionState s)
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Assert(s->parent!=NULL);
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Assert(s->state==TRANS_INPROGRESS);
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/*
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* Ensure parent(s) have XIDs, so that a child always has an XID later
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* than its parent. Musn't recurse here, or we might get a stack overflow
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* if we're at the bottom of a huge stack of subtransactions none of which
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* have XIDs yet.
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*/
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if (!TransactionIdIsValid(s->parent->transactionId))
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AssignSubTransactionId(s->parent);
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{
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TransactionStatep=s->parent;
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TransactionState*parents;
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size_tparentOffset=0;
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parents=palloc(sizeof(TransactionState)*s->nestingLevel);
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while (p!=NULL&& !TransactionIdIsValid(p->transactionId))
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{
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parents[parentOffset++]=p;
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p=p->parent;
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}
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/*
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* This is technically a recursive call, but the recursion will
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* never be more than one layer deep.
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*/
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while (parentOffset!=0)
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AssignSubTransactionId(parents[--parentOffset]);
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pfree(parents);
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}
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/*
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* Generate a new Xid and record it in PG_PROC and pg_subtrans.

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