You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.

Alexander Korotkov 4b754d6c16 Avoid full scan of GIN indexes when possible ... The strategy of GIN index scan is driven by opclass-specific extract_query method. This method that needed search mode is GIN_SEARCH_MODE_ALL. This mode means that matching tuple may contain none of extracted entries. Simple example is '!term' tsquery, which doesn't need any term to exist in matching tsvector. In order to handle such scan key GIN calculates virtual entry, which contains all TIDs of all entries of attribute. In fact this is full scan of index attribute. And typically this is very slow, but allows to handle some queries correctly in GIN. However, current algorithm calculate such virtual entry for each GIN_SEARCH_MODE_ALL scan key even if they are multiple for the same attribute. This is clearly not optimal. This commit improves the situation by introduction of "exclude only" scan keys. Such scan keys are not capable to return set of matching TIDs. Instead, they are capable only to filter TIDs produced by normal scan keys. Therefore, each attribute should contain at least one normal scan key, while rest of them may be "exclude only" if search mode is GIN_SEARCH_MODE_ALL. The same optimization might be applied to the whole scan, not per-attribute. But that leads to NULL values elimination problem. There is trade-off between multiple possible ways to do this. We probably want to do this later using some cost-based decision algorithm. Discussion: https://postgr.es/m/CAOBaU_YGP5-BEt5Cc0%3DzMve92vocPzD%2BXiZgiZs1kjY0cj%3DXBg%40mail.gmail.com Author: Nikita Glukhov, Alexander Korotkov, Tom Lane, Julien Rouhaud Reviewed-by: Julien Rouhaud, Tomas Vondra, Tom Lane		6 years ago
..
data	Add files forgotten in f576b17cd6	9 years ago
expected	Avoid full scan of GIN indexes when possible	6 years ago
sql	Avoid full scan of GIN indexes when possible	6 years ago
.gitignore	Support "make check" in contrib	14 years ago
Makefile	Split all OBJS style lines in makefiles into one-line-per-entry style.	6 years ago
pg_trgm--1.0--1.1.sql	Fix typo in update scripts for some contrib modules.	12 years ago
pg_trgm--1.1--1.2.sql	Add word_similarity to pg_trgm contrib module.	9 years ago
pg_trgm--1.2--1.3.sql	pg_trgm's set_limit() function is parallel unsafe, not parallel restricted.	9 years ago
pg_trgm--1.3--1.4.sql	Add strict_word_similarity to pg_trgm module	7 years ago
pg_trgm--1.3.sql	pg_trgm's set_limit() function is parallel unsafe, not parallel restricted.	9 years ago
pg_trgm--unpackaged--1.0.sql	Fix typos in some error messages thrown by extension scripts when fed to psql.	11 years ago
pg_trgm.control	Add strict_word_similarity to pg_trgm module	7 years ago
trgm.h	Phase 2 pgindent run for v12.	6 years ago
trgm_gin.c	Make the order of the header file includes consistent in contrib modules.	6 years ago
trgm_gist.c	Make the order of the header file includes consistent in contrib modules.	6 years ago
trgm_op.c	Add reusable routine for making arrays unique.	6 years ago
trgm_regexp.c	Update copyrights for 2020	6 years ago