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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2022-03-24 11:47:41 -0400 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2022-03-24 11:47:41 -0400 |
| commit | 0bd7af082ace135581bb13a6bd2d88e68c66a3e0 (patch) | |
| tree | 412ad873ef762b761baaab0577cb4d36b6c0a240 /src/include | |
| parent | a47651447f01562dac2e007db03733e750d45b6b (diff) | |
| download | postgresql-0bd7af082ace135581bb13a6bd2d88e68c66a3e0.tar.gz postgresql-0bd7af082ace135581bb13a6bd2d88e68c66a3e0.zip | |
Invent recursive_worktable_factor GUC to replace hard-wired constant.
Up to now, the planner estimated the size of a recursive query's
worktable as 10 times the size of the non-recursive term. It's hard
to see how to do significantly better than that automatically, but
we can give users control over the multiplier to allow tuning for
specific use-cases. The default behavior remains the same.
Simon Riggs
Discussion: https://postgr.es/m/CANbhV-EuaLm4H3g0+BSTYHEGxJj3Kht0R+rJ8vT57Dejnh=_nA@mail.gmail.com
Diffstat (limited to 'src/include')
| -rw-r--r-- | src/include/optimizer/cost.h | 2 | ||||
| -rw-r--r-- | src/include/optimizer/optimizer.h | 1 |
2 files changed, 3 insertions, 0 deletions
diff --git a/src/include/optimizer/cost.h b/src/include/optimizer/cost.h index 356a51f370a..bc12071af6e 100644 --- a/src/include/optimizer/cost.h +++ b/src/include/optimizer/cost.h @@ -29,6 +29,8 @@ #define DEFAULT_PARALLEL_TUPLE_COST 0.1 #define DEFAULT_PARALLEL_SETUP_COST 1000.0 +/* defaults for non-Cost parameters */ +#define DEFAULT_RECURSIVE_WORKTABLE_FACTOR 10.0 #define DEFAULT_EFFECTIVE_CACHE_SIZE 524288 /* measured in pages */ typedef enum diff --git a/src/include/optimizer/optimizer.h b/src/include/optimizer/optimizer.h index 6b8ee0c69fa..2302ab6d546 100644 --- a/src/include/optimizer/optimizer.h +++ b/src/include/optimizer/optimizer.h @@ -91,6 +91,7 @@ extern PGDLLIMPORT double cpu_index_tuple_cost; extern PGDLLIMPORT double cpu_operator_cost; extern PGDLLIMPORT double parallel_tuple_cost; extern PGDLLIMPORT double parallel_setup_cost; +extern PGDLLIMPORT double recursive_worktable_factor; extern PGDLLIMPORT int effective_cache_size; extern double clamp_row_est(double nrows); |