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Commitb8778c4

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Add lossy indicator to TBMIterateResult
TBMIterateResult->ntuples is -1 when the page in the bitmap is lossy.Add an explicit lossy indicator so that we can move ntuples out of theTBMIterateResult in a future commit.Discussion:https://postgr.es/m/CA%2BhUKGLHbKP3jwJ6_%2BhnGi37Pw3BD5j2amjV3oSk7j-KyCnY7Q%40mail.gmail.com
1 parentc56e8af commitb8778c4

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4 files changed

+20
-12
lines changed

4 files changed

+20
-12
lines changed

‎src/backend/access/gin/ginget.c

Lines changed: 4 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -827,7 +827,7 @@ entryGetItem(GinState *ginstate, GinScanEntry entry,
827827
* in the bitmap.
828828
*/
829829
while (entry->matchResult==NULL||
830-
(entry->matchResult->ntuples >=0&&
830+
(!entry->matchResult->lossy&&
831831
entry->offset >=entry->matchResult->ntuples)||
832832
entry->matchResult->blockno<advancePastBlk||
833833
(ItemPointerIsLossyPage(&advancePast)&&
@@ -860,7 +860,7 @@ entryGetItem(GinState *ginstate, GinScanEntry entry,
860860
* We're now on the first page after advancePast which has any
861861
* items on it. If it's a lossy result, return that.
862862
*/
863-
if (entry->matchResult->ntuples<0)
863+
if (entry->matchResult->lossy)
864864
{
865865
ItemPointerSetLossyPage(&entry->curItem,
866866
entry->matchResult->blockno);
@@ -879,6 +879,8 @@ entryGetItem(GinState *ginstate, GinScanEntry entry,
879879
*/
880880
if (entry->matchResult->blockno==advancePastBlk)
881881
{
882+
Assert(entry->matchResult->ntuples>0);
883+
882884
/*
883885
* First, do a quick check against the last offset on the
884886
* page. If that's > advancePast, so are all the other

‎src/backend/access/heap/heapam_handler.c

Lines changed: 5 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -2170,7 +2170,7 @@ heapam_scan_bitmap_next_block(TableScanDesc scan,
21702170
VM_ALL_VISIBLE(scan->rs_rd,tbmres->blockno,&bscan->rs_vmbuffer))
21712171
{
21722172
/* can't be lossy in the skip_fetch case */
2173-
Assert(tbmres->ntuples >=0);
2173+
Assert(!tbmres->lossy);
21742174
Assert(bscan->rs_empty_tuples_pending >=0);
21752175

21762176
bscan->rs_empty_tuples_pending+=tbmres->ntuples;
@@ -2207,7 +2207,7 @@ heapam_scan_bitmap_next_block(TableScanDesc scan,
22072207
/*
22082208
* We need two separate strategies for lossy and non-lossy cases.
22092209
*/
2210-
if (tbmres->ntuples >=0)
2210+
if (!tbmres->lossy)
22112211
{
22122212
/*
22132213
* Bitmap is non-lossy, so we just look through the offsets listed in
@@ -2268,10 +2268,10 @@ heapam_scan_bitmap_next_block(TableScanDesc scan,
22682268
Assert(ntup <=MaxHeapTuplesPerPage);
22692269
hscan->rs_ntuples=ntup;
22702270

2271-
if (tbmres->ntuples >=0)
2272-
(*exact_pages)++;
2273-
else
2271+
if (tbmres->lossy)
22742272
(*lossy_pages)++;
2273+
else
2274+
(*exact_pages)++;
22752275

22762276
/*
22772277
* Return true to indicate that a valid block was found and the bitmap is

‎src/backend/nodes/tidbitmap.c

Lines changed: 8 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -961,12 +961,13 @@ tbm_advance_schunkbit(PagetableEntry *chunk, int *schunkbitp)
961961
*
962962
* Returns a TBMIterateResult representing one page, or NULL if there are
963963
* no more pages to scan. Pages are guaranteed to be delivered in numerical
964-
* order. Ifresult->ntuples < 0, then the bitmap is "lossy" and failed to
964+
* order. Iflossy is true, then the bitmap is "lossy" and failed to
965965
* remember the exact tuples to look at on this page --- the caller must
966966
* examine all tuples on the page and check if they meet the intended
967-
* condition. If result->recheck is true, only the indicated tuples need
967+
* condition. result->ntuples is set to -1 when the bitmap is lossy.
968+
* If result->recheck is true, only the indicated tuples need
968969
* be examined, but the condition must be rechecked anyway. (For ease of
969-
* testing, recheck is always set true whenntuples < 0.)
970+
* testing, recheck is always set true whenlossy is true.)
970971
*/
971972
TBMIterateResult*
972973
tbm_private_iterate(TBMPrivateIterator*iterator)
@@ -1012,6 +1013,7 @@ tbm_private_iterate(TBMPrivateIterator *iterator)
10121013
/* Return a lossy page indicator from the chunk */
10131014
output->blockno=chunk_blockno;
10141015
output->ntuples=-1;
1016+
output->lossy= true;
10151017
output->recheck= true;
10161018
iterator->schunkbit++;
10171019
returnoutput;
@@ -1033,6 +1035,7 @@ tbm_private_iterate(TBMPrivateIterator *iterator)
10331035
ntuples=tbm_extract_page_tuple(page,output);
10341036
output->blockno=page->blockno;
10351037
output->ntuples=ntuples;
1038+
output->lossy= false;
10361039
output->recheck=page->recheck;
10371040
iterator->spageptr++;
10381041
returnoutput;
@@ -1105,6 +1108,7 @@ tbm_shared_iterate(TBMSharedIterator *iterator)
11051108
/* Return a lossy page indicator from the chunk */
11061109
output->blockno=chunk_blockno;
11071110
output->ntuples=-1;
1111+
output->lossy= true;
11081112
output->recheck= true;
11091113
istate->schunkbit++;
11101114

@@ -1122,6 +1126,7 @@ tbm_shared_iterate(TBMSharedIterator *iterator)
11221126
ntuples=tbm_extract_page_tuple(page,output);
11231127
output->blockno=page->blockno;
11241128
output->ntuples=ntuples;
1129+
output->lossy= false;
11251130
output->recheck=page->recheck;
11261131
istate->spageptr++;
11271132

‎src/include/nodes/tidbitmap.h

Lines changed: 3 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -54,9 +54,10 @@ typedef struct TBMIterator
5454
typedefstructTBMIterateResult
5555
{
5656
BlockNumberblockno;/* page number containing tuples */
57-
intntuples;/* -1 indicates lossy result */
57+
intntuples;/* -1 when lossy */
58+
boollossy;
5859
boolrecheck;/* should the tuples be rechecked? */
59-
/* Note: recheck is always true ifntuples < 0 */
60+
/* Note: recheck is always true iflossy */
6061
OffsetNumberoffsets[FLEXIBLE_ARRAY_MEMBER];
6162
}TBMIterateResult;
6263

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