Show sizes of FETCH queries as constants in pg_stat_statements Prior to this patch, every FETCH call would generate a unique queryId with a different size specified. Depending on the workloads, this could lead to a significant bloat in pg_stat_statements, as repeatedly calling a specific cursor would result in a new queryId each time. For example, FETCH 1 c1; and FETCH 2 c1; would produce different queryIds.
This patch improves the situation by normalizing the fetch size, so as semantically similar statements generate the same queryId. As a result, statements like the below, which differ syntactically but have the same effect, will now share a single queryId: FETCH FROM c1 FETCH NEXT c1 FETCH 1 c1 In order to do a normalization based on the keyword used in FETCH, FetchStmt is tweaked with a new FetchDirectionKeywords. This matters for "howMany", which could be set to a negative value depending on the direction, and we want to normalize the queries with enough information about the direction keywords provided, including RELATIVE, ABSOLUTE or all the ALL variants. Author: Sami Imseih <samims...@gmail.com> Discussion: https://postgr.es/m/caa5rz0ta6lbhcg2qss+kum850bzc_+zghv7ug6bxw22tnyf...@mail.gmail.com Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/bee23ea4ddc46198c95a4e73a83f453c09e04bf8 Modified Files -------------- contrib/pg_stat_statements/expected/cursors.out | 141 ++++++++++++++++++++- .../pg_stat_statements/expected/level_tracking.out | 4 +- contrib/pg_stat_statements/expected/utility.out | 2 +- contrib/pg_stat_statements/sql/cursors.sql | 43 +++++++ src/backend/parser/gram.y | 50 ++++++-- src/include/nodes/parsenodes.h | 35 ++++- src/tools/pgindent/typedefs.list | 1 + 7 files changed, 259 insertions(+), 17 deletions(-)
