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Move TupleTableSlots boolean member into one flag variable.

Browse Source 
There's several reasons for this change:
1) It reduces the total size of TupleTableSlot / reduces alignment
   padding, making the commonly accessed members fit into a single
   cacheline (but we currently do not force proper alignment, so
   that's not yet guaranteed to be helpful)
2) Combining the booleans into a flag allows to combine read/writes
   from memory.
3) With the upcoming slot abstraction changes, it allows to have core
   and extended flags, in a memory efficient way.

Author: Ashutosh Bapat and Andres Freund
Discussion: https://postgr.es/m/20180220224318.gw4oe5jadhpmcdnm@alap3.anarazel.de
This commit is contained in:
Andres Freund
2018-10-15 15:24:33 -07:00
parent 9d906f1119
commit c5257345ef
8 changed files with 116 additions and 72 deletions
Download Patch File Download Diff File Expand all files Collapse all files

96
src/backend/executor/execTuples.c
View File

@ -101,11 +101,10 @@ MakeTupleTableSlot(TupleDesc tupleDesc)
slot = palloc0(sz);
slot->type = T_TupleTableSlot;
slot->tts_isempty = true;
slot->tts_shouldFree = false;
slot->tts_shouldFreeMin = false;
slot->tts_flags |= TTS_FLAG_EMPTY;
if (tupleDesc != NULL)
slot->tts_flags |= TTS_FLAG_FIXED;
slot->tts_tuple = NULL;
slot->tts_fixedTupleDescriptor = tupleDesc != NULL;
slot->tts_tupleDescriptor = tupleDesc;
slot->tts_mcxt = CurrentMemoryContext;
slot->tts_buffer = InvalidBuffer;
@ -176,7 +175,7 @@ ExecResetTupleTable(List *tupleTable, /* tuple table */
/* If shouldFree, release memory occupied by the slot itself */
if (shouldFree)
{
if (!slot->tts_fixedTupleDescriptor)
if (!TTS_FIXED(slot))
{
if (slot->tts_values)
pfree(slot->tts_values);
@ -224,7 +223,7 @@ ExecDropSingleTupleTableSlot(TupleTableSlot *slot)
ExecClearTuple(slot);
if (slot->tts_tupleDescriptor)
ReleaseTupleDesc(slot->tts_tupleDescriptor);
if (!slot->tts_fixedTupleDescriptor)
if (!TTS_FIXED(slot))
{
if (slot->tts_values)
pfree(slot->tts_values);
@ -254,7 +253,7 @@ void
ExecSetSlotDescriptor(TupleTableSlot *slot, /* slot to change */
TupleDesc tupdesc) /* new tuple descriptor */
{
Assert(!slot->tts_fixedTupleDescriptor);
Assert(!TTS_FIXED(slot));
/* For safety, make sure slot is empty before changing it */
ExecClearTuple(slot);
@ -325,17 +324,23 @@ ExecStoreHeapTuple(HeapTuple tuple,
/*
* Free any old physical tuple belonging to the slot.
*/
if (slot->tts_shouldFree)
if (TTS_SHOULDFREE(slot))
{
heap_freetuple(slot->tts_tuple);
if (slot->tts_shouldFreeMin)
slot->tts_flags &= ~TTS_FLAG_SHOULDFREE;
}
if (TTS_SHOULDFREEMIN(slot))
{
heap_free_minimal_tuple(slot->tts_mintuple);
slot->tts_flags &= ~TTS_FLAG_SHOULDFREEMIN;
}
/*
* Store the new tuple into the specified slot.
*/
slot->tts_isempty = false;
slot->tts_shouldFree = shouldFree;
slot->tts_shouldFreeMin = false;
slot->tts_flags &= ~TTS_FLAG_EMPTY;
if (shouldFree)
slot->tts_flags |= TTS_FLAG_SHOULDFREE;
slot->tts_tuple = tuple;
slot->tts_mintuple = NULL;
@ -382,17 +387,21 @@ ExecStoreBufferHeapTuple(HeapTuple tuple,
/*
* Free any old physical tuple belonging to the slot.
*/
if (slot->tts_shouldFree)
if (TTS_SHOULDFREE(slot))
{
heap_freetuple(slot->tts_tuple);
if (slot->tts_shouldFreeMin)
slot->tts_flags &= ~TTS_FLAG_SHOULDFREE;
}
if (TTS_SHOULDFREEMIN(slot))
{
heap_free_minimal_tuple(slot->tts_mintuple);
slot->tts_flags &= ~TTS_FLAG_SHOULDFREEMIN;
}
/*
* Store the new tuple into the specified slot.
*/
slot->tts_isempty = false;
slot->tts_shouldFree = false;
slot->tts_shouldFreeMin = false;
slot->tts_flags &= ~TTS_FLAG_EMPTY;
slot->tts_tuple = tuple;
slot->tts_mintuple = NULL;
@ -442,10 +451,16 @@ ExecStoreMinimalTuple(MinimalTuple mtup,
/*
* Free any old physical tuple belonging to the slot.
*/
if (slot->tts_shouldFree)
if (TTS_SHOULDFREE(slot))
{
heap_freetuple(slot->tts_tuple);
if (slot->tts_shouldFreeMin)
slot->tts_flags &= ~TTS_FLAG_SHOULDFREE;
}
if (TTS_SHOULDFREEMIN(slot))
{
heap_free_minimal_tuple(slot->tts_mintuple);
slot->tts_flags &= ~TTS_FLAG_SHOULDFREEMIN;
}
/*
* Drop the pin on the referenced buffer, if there is one.
@ -458,9 +473,9 @@ ExecStoreMinimalTuple(MinimalTuple mtup,
/*
* Store the new tuple into the specified slot.
*/
slot->tts_isempty = false;
slot->tts_shouldFree = false;
slot->tts_shouldFreeMin = shouldFree;
slot->tts_flags &= ~TTS_FLAG_EMPTY;
if (shouldFree)
slot->tts_flags |= TTS_FLAG_SHOULDFREEMIN;
slot->tts_tuple = &slot->tts_minhdr;
slot->tts_mintuple = mtup;
@ -493,15 +508,19 @@ ExecClearTuple(TupleTableSlot *slot) /* slot in which to store tuple */
/*
* Free the old physical tuple if necessary.
*/
if (slot->tts_shouldFree)
if (TTS_SHOULDFREE(slot))
{
heap_freetuple(slot->tts_tuple);
if (slot->tts_shouldFreeMin)
slot->tts_flags &= ~TTS_FLAG_SHOULDFREE;
}
if (TTS_SHOULDFREEMIN(slot))
{
heap_free_minimal_tuple(slot->tts_mintuple);
slot->tts_flags &= ~TTS_FLAG_SHOULDFREEMIN;
}
slot->tts_tuple = NULL;
slot->tts_mintuple = NULL;
slot->tts_shouldFree = false;
slot->tts_shouldFreeMin = false;
/*
* Drop the pin on the referenced buffer, if there is one.
@ -514,7 +533,7 @@ ExecClearTuple(TupleTableSlot *slot) /* slot in which to store tuple */
/*
* Mark it empty.
*/
slot->tts_isempty = true;
slot->tts_flags |= TTS_FLAG_EMPTY;
slot->tts_nvalid = 0;
return slot;
@ -539,9 +558,9 @@ ExecStoreVirtualTuple(TupleTableSlot *slot)
*/
Assert(slot != NULL);
Assert(slot->tts_tupleDescriptor != NULL);
Assert(slot->tts_isempty);
Assert(TTS_EMPTY(slot));
slot->tts_isempty = false;
slot->tts_flags &= ~TTS_FLAG_EMPTY;
slot->tts_nvalid = slot->tts_tupleDescriptor->natts;
return slot;
@ -595,7 +614,7 @@ ExecCopySlotTuple(TupleTableSlot *slot)
* sanity checks
*/
Assert(slot != NULL);
Assert(!slot->tts_isempty);
Assert(!TTS_EMPTY(slot));
/*
* If we have a physical tuple (either format) then just copy it.
@ -627,7 +646,7 @@ ExecCopySlotMinimalTuple(TupleTableSlot *slot)
* sanity checks
*/
Assert(slot != NULL);
Assert(!slot->tts_isempty);
Assert(!TTS_EMPTY(slot));
/*
* If we have a physical tuple then just copy it. Prefer to copy
@ -675,7 +694,7 @@ ExecFetchSlotTuple(TupleTableSlot *slot)
* sanity checks
*/
Assert(slot != NULL);
Assert(!slot->tts_isempty);
Assert(!TTS_EMPTY(slot));
/*
* If we have a regular physical tuple then just return it.
@ -724,7 +743,8 @@ ExecFetchSlotMinimalTuple(TupleTableSlot *slot)
* sanity checks
*/
Assert(slot != NULL);
Assert(!slot->tts_isempty);
Assert(!TTS_EMPTY(slot));
/*
* If we have a minimal physical tuple (local or not) then just return it.
@ -741,7 +761,7 @@ ExecFetchSlotMinimalTuple(TupleTableSlot *slot)
*/
oldContext = MemoryContextSwitchTo(slot->tts_mcxt);
slot->tts_mintuple = ExecCopySlotMinimalTuple(slot);
slot->tts_shouldFreeMin = true;
slot->tts_flags |= TTS_FLAG_SHOULDFREEMIN;
MemoryContextSwitchTo(oldContext);
/*
@ -797,13 +817,13 @@ ExecMaterializeSlot(TupleTableSlot *slot)
* sanity checks
*/
Assert(slot != NULL);
Assert(!slot->tts_isempty);
Assert(!TTS_EMPTY(slot));
/*
* If we have a regular physical tuple, and it's locally palloc'd, we have
* nothing to do.
*/
if (slot->tts_tuple && slot->tts_shouldFree)
if (slot->tts_tuple && TTS_SHOULDFREE(slot))
return slot->tts_tuple;
/*
@ -815,7 +835,7 @@ ExecMaterializeSlot(TupleTableSlot *slot)
*/
oldContext = MemoryContextSwitchTo(slot->tts_mcxt);
slot->tts_tuple = ExecCopySlotTuple(slot);
slot->tts_shouldFree = true;
slot->tts_flags |= TTS_FLAG_SHOULDFREE;
MemoryContextSwitchTo(oldContext);
/*
@ -842,7 +862,7 @@ ExecMaterializeSlot(TupleTableSlot *slot)
* storage, we must not pfree it now, since callers might have already
* fetched datum pointers referencing it.)
*/
if (!slot->tts_shouldFreeMin)
if (!TTS_SHOULDFREEMIN(slot))
slot->tts_mintuple = NULL;
return slot->tts_tuple;

2
src/backend/executor/nodeAgg.c
View File

@ -1080,7 +1080,7 @@ prepare_projection_slot(AggState *aggstate, TupleTableSlot *slot, int currentSet
aggstate->grouped_cols = grouped_cols;
if (slot->tts_isempty)
if (TTS_EMPTY(slot))
{
/*
* Force all values to be NULL if working on an empty input tuple

2
src/backend/executor/nodeModifyTable.c
View File

@ -699,7 +699,7 @@ ExecDelete(ModifyTableState *mtstate,
* RETURNING expressions might reference the tableoid column, so
* initialize t_tableOid before evaluating them.
*/
if (slot->tts_isempty)
if (TTS_EMPTY(slot))
ExecStoreAllNullTuple(slot);
tuple = ExecMaterializeSlot(slot);
tuple->t_tableOid = RelationGetRelid(resultRelationDesc);