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Commit10db3de

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Fix failure to account for memory used by tuplestore_putvalues().
This oversight could result in a tuplestore using much more than theintended amount of memory. It would only happen in a code path that loadeda tuplestore via tuplestore_putvalues(), and many of those won't emit hugeamounts of data; but cases such as holdable cursors and plpgsql's RETURNNEXT command could have the problem. The fix ensures that the tuplestorewill switch to write-to-disk mode when it overruns work_mem.The potential overrun was finite, because we would still count the spaceused by the tuple pointer array, so the tuplestore code would eventuallyflip into write-to-disk mode anyway. When storing wide tuples we wouldgo far past the expected work_mem usage before that happened; but thismay account for the lack of prior reports.Back-patch to 8.4, where tuplestore_putvalues was introduced.Per bug #6061 from Yann Delorme.
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‎src/backend/utils/sort/tuplestore.c

Lines changed: 5 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -570,7 +570,8 @@ tuplestore_puttuple(Tuplestorestate *state, HeapTuple tuple)
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MemoryContextoldcxt=MemoryContextSwitchTo(state->context);
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/*
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* Copy the tuple.(Must do this even in WRITEFILE case.)
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* Copy the tuple. (Must do this even in WRITEFILE case. Note that
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* COPYTUP includes USEMEM, so we needn't do that here.)
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*/
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tuple=COPYTUP(state,tuple);
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@@ -580,9 +581,8 @@ tuplestore_puttuple(Tuplestorestate *state, HeapTuple tuple)
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}
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/*
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* Similar to tuplestore_puttuple(), but start from the values + nulls
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* array. This avoids requiring that the caller construct a HeapTuple,
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* saving a copy.
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* Similar to tuplestore_puttuple(), but work from values + nulls arrays.
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* This avoids an extra tuple-construction operation.
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*/
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void
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tuplestore_putvalues(Tuplestorestate*state,TupleDesctdesc,
@@ -592,6 +592,7 @@ tuplestore_putvalues(Tuplestorestate *state, TupleDesc tdesc,
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MemoryContextoldcxt=MemoryContextSwitchTo(state->context);
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tuple=heap_form_minimal_tuple(tdesc,values,isnull);
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USEMEM(state,GetMemoryChunkSpace(tuple));
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tuplestore_puttuple_common(state, (void*)tuple);
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