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Commitc759395

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Code review for Parallel Append.
- Remove unnecessary #include mistakenly added in execnodes.h.- Fix mistake in comment in choose_next_subplan_for_leader.- Adjust row estimates in cost_append for a possibly-different parallel divisor.- Clamp row estimates in cost_append after operations that may not produce integers.Amit Kapila, with cosmetic adjustments by me.Discussion:http://postgr.es/m/CAA4eK1+qcbeai3coPpRW=GFCzFeLUsuY4T-AKHqMjxpEGZBPQg@mail.gmail.com
1 parent934c798 commitc759395

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3 files changed

+15
-9
lines changed

3 files changed

+15
-9
lines changed

‎src/backend/executor/nodeAppend.c

Lines changed: 3 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -446,10 +446,9 @@ choose_next_subplan_for_leader(AppendState *node)
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*
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*We start from the first plan and advance through the list;
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*when we get back to the end, we loop back to the first
449-
*nonpartial plan. This assigns the non-partial plans first
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*in order of descending cost and then spreads out the
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*workers as evenly as possible across the remaining partial
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*plans.
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*partial plan. This assigns the non-partial plans first in
450+
*order of descending cost and then spreads out the workers
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*as evenly as possible across the remaining partial plans.
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* ----------------------------------------------------------------
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*/
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staticbool

‎src/backend/optimizer/path/costsize.c

Lines changed: 12 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -1883,18 +1883,26 @@ cost_append(AppendPath *apath)
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subpath->startup_cost);
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/*
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* Apply parallel divisor to non-partial subpaths. Also add the
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* cost of partial paths to the total cost, but ignore non-partial
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* paths for now.
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* Apply parallel divisor to subpaths. Scale the number of rows
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* for each partial subpath based on the ratio of the parallel
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* divisor originally used for the subpath to the one we adopted.
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* Also add the cost of partial paths to the total cost, but
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* ignore non-partial paths for now.
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*/
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if (i<apath->first_partial_path)
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apath->path.rows+=subpath->rows /parallel_divisor;
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else
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{
1894-
apath->path.rows+=subpath->rows;
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doublesubpath_parallel_divisor;
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1898+
subpath_parallel_divisor=get_parallel_divisor(subpath);
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apath->path.rows+=subpath->rows* (subpath_parallel_divisor /
1900+
parallel_divisor);
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apath->path.total_cost+=subpath->total_cost;
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}
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1904+
apath->path.rows=clamp_row_est(apath->path.rows);
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i++;
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}
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‎src/include/nodes/execnodes.h

Lines changed: 0 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -21,7 +21,6 @@
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#include"lib/pairingheap.h"
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#include"nodes/params.h"
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#include"nodes/plannodes.h"
24-
#include"storage/spin.h"
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#include"utils/hsearch.h"
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#include"utils/queryenvironment.h"
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#include"utils/reltrigger.h"

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