Add a planner support function for starts_with().
This fills in some gaps in planner support for starts_with() and
the equivalent ^@ operator:
* A condition such as "textcol ^@ constant" can now use a regular
btree index, not only an SP-GiST index, so long as the index's
collation is C. (This works just like "textcol LIKE 'foo%'".)
* "starts_with(textcol, constant)" can be optimized the same as
"textcol ^@ constant".
* Fixed-prefix LIKE and regex patterns are now more like starts_with()
in another way: if you apply one to an SPGiST-indexed column, you'll
get an index condition using ^@ rather than two index conditions with
>= and <.
Per a complaint from Shay Rojansky. Patch by me; thanks to
Nathan Bossart for review.
Discussion: https://postgr.es/m/232599.1633800229@sss.pgh.pa.us
Branch
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master
Details
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https://git.postgresql.org/pg/commitdiff/a148f8bc04b9980f019ea0d4b89311cf0bdc22b7
Modified Files
--------------
src/backend/utils/adt/like_support.c | 65 ++++++++++++++++-------
src/include/catalog/catversion.h | 2 +-
src/include/catalog/pg_operator.dat | 2 +-
src/include/catalog/pg_proc.dat | 8 ++-
src/test/regress/expected/create_index_spgist.out | 33 ++++++++++++
src/test/regress/sql/create_index_spgist.sql | 8 +++
6 files changed, 95 insertions(+), 23 deletions(-)
