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Add a new GUC and a reloption to enable inserts in parallel-mode.

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Commit 05c8482f7f added the implementation of parallel SELECT for
"INSERT INTO ... SELECT ..." which may incur non-negligible overhead in
the additional parallel-safety checks that it performs, even when, in the
end, those checks determine that parallelism can't be used. This is
normally only ever a problem in the case of when the target table has a
large number of partitions.

A new GUC option "enable_parallel_insert" is added, to allow insert in
parallel-mode. The default is on.

In addition to the GUC option, the user may want a mechanism to allow
inserts in parallel-mode with finer granularity at table level. The new
table option "parallel_insert_enabled" allows this. The default is true.

Author: "Hou, Zhijie"
Reviewed-by: Greg Nancarrow, Amit Langote, Takayuki Tsunakawa, Amit Kapila
Discussion: https://postgr.es/m/CAA4eK1K-cW7svLC2D7DHoGHxdAdg3P37BLgebqBOC2ZLc9a6QQ%40mail.gmail.com
Discussion: https://postgr.es/m/CAJcOf-cXnB5cnMKqWEp2E2z7Mvcd04iLVmV=qpFJrR3AcrTS3g@mail.gmail.com
This commit is contained in:
Amit Kapila
2021-03-18 07:25:27 +05:30
parent 5f79580ad6
commit c8f78b6161
15 changed files with 240 additions and 15 deletions
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1
src/include/optimizer/cost.h
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@@ -47,6 +47,7 @@ typedef enum
/* parameter variables and flags (see also optimizer.h) */
extern PGDLLIMPORT Cost disable_cost;
extern PGDLLIMPORT int max_parallel_workers_per_gather;
extern PGDLLIMPORT bool enable_parallel_insert;
extern PGDLLIMPORT bool enable_seqscan;
extern PGDLLIMPORT bool enable_indexscan;
extern PGDLLIMPORT bool enable_indexonlyscan;