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robertmhaasrobertmhaas
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Support parallel bitmap heap scans.
The index is scanned by a single process, but then all cooperating processes can iterate jointly over the resulting set of heap blocks. In the future, we might also want to support using a parallel bitmap index scan to set up for a parallel bitmap heap scan, but that's a job for another day. Dilip Kumar, with some corrections and cosmetic changes by me. The larger patch set of which this is a part has been reviewed and tested by (at least) Andres Freund, Amit Khandekar, Tushar Ahuja, Rafia Sabih, Haribabu Kommi, Thomas Munro, and me. Discussion: http://postgr.es/m/CAFiTN-uc4=0WxRGfCzs-xfkMYcSEWUC-Fon6thkJGjkh9i=13A@mail.gmail.com
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24 files changed

+612
-55
lines changed

24 files changed

+612
-55
lines changed

‎doc/src/sgml/monitoring.sgml

Lines changed: 5 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1211,7 +1211,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser
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<entry>Waiting in an extension.</entry>
12121212
</row>
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<row>
1214-
<entry morerows="10"><literal>IPC</></entry>
1214+
<entry morerows="11"><literal>IPC</></entry>
12151215
<entry><literal>BgWorkerShutdown</></entry>
12161216
<entry>Waiting for background worker to shut down.</entry>
12171217
</row>
@@ -1247,6 +1247,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser
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<entry><literal>ParallelFinish</></entry>
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<entry>Waiting for parallel workers to finish computing.</entry>
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</row>
1250+
<row>
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<entry><literal>ParallelBitmapPopulate</></entry>
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<entry>Waiting for the leader to populate the TidBitmap.</entry>
1253+
</row>
12501254
<row>
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<entry><literal>SafeSnapshot</></entry>
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<entry>Waiting for a snapshot for a <literal>READ ONLY DEFERRABLE</> transaction.</entry>

‎src/backend/access/heap/heapam.c

Lines changed: 16 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1753,6 +1753,22 @@ heap_parallelscan_nextpage(HeapScanDesc scan)
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return page;
17541754
}
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1756+
/* ----------------
1757+
* heap_update_snapshot
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*
1759+
* Update snapshot info in heap scan descriptor.
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* ----------------
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*/
1762+
void
1763+
heap_update_snapshot(HeapScanDesc scan, Snapshot snapshot)
1764+
{
1765+
Assert(IsMVCCSnapshot(snapshot));
1766+
1767+
RegisterSnapshot(snapshot);
1768+
scan->rs_snapshot = snapshot;
1769+
scan->rs_temp_snap = true;
1770+
}
1771+
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/* ----------------
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* heap_getnext - retrieve next tuple in scan
17581774
*

‎src/backend/executor/execParallel.c

Lines changed: 14 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -25,6 +25,7 @@
2525

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#include "executor/execParallel.h"
2727
#include "executor/executor.h"
28+
#include "executor/nodeBitmapHeapscan.h"
2829
#include "executor/nodeCustom.h"
2930
#include "executor/nodeForeignscan.h"
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#include "executor/nodeSeqscan.h"
@@ -217,6 +218,10 @@ ExecParallelEstimate(PlanState *planstate, ExecParallelEstimateContext *e)
217218
ExecCustomScanEstimate((CustomScanState *) planstate,
218219
e->pcxt);
219220
break;
221+
case T_BitmapHeapScanState:
222+
ExecBitmapHeapEstimate((BitmapHeapScanState *) planstate,
223+
e->pcxt);
224+
break;
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default:
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break;
222227
}
@@ -277,6 +282,11 @@ ExecParallelInitializeDSM(PlanState *planstate,
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ExecCustomScanInitializeDSM((CustomScanState *) planstate,
278283
d->pcxt);
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break;
285+
case T_BitmapHeapScanState:
286+
ExecBitmapHeapInitializeDSM((BitmapHeapScanState *) planstate,
287+
d->pcxt);
288+
break;
289+
280290
default:
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break;
282292
}
@@ -775,6 +785,10 @@ ExecParallelInitializeWorker(PlanState *planstate, shm_toc *toc)
775785
ExecCustomScanInitializeWorker((CustomScanState *) planstate,
776786
toc);
777787
break;
788+
case T_BitmapHeapScanState:
789+
ExecBitmapHeapInitializeWorker(
790+
(BitmapHeapScanState *) planstate, toc);
791+
break;
778792
default:
779793
break;
780794
}

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