Michael Paquier 09a72188cd Avoid some overhead with open and close of catalog indexes
This commit improves two code paths to open and close indexes a
minimum amount of times when doing a series of catalog updates or
inserts.  CatalogTupleInsert() is costly when using it for multiple
inserts or updates compared to CatalogTupleInsertWithInfo(), as it would
need to open and close the indexes of the catalog worked each time an
operation is done.

This commit updates the following places:
- REINDEX CONCURRENTLY when copying statistics from one index relation
to the other.  Multi-INSERTs are avoided here, as this would begin to
show benefits only for indexes with multiple expressions, for example,
which may not be the most common pattern.  This change is noticeable in
profiles with indexes having many expressions, for example, and it would
improve any callers of CopyStatistics().
- Update of statistics on ANALYZE, that mixes inserts and updates.
In each case, the catalog indexes are opened only if at least one
insertion and/or update is required, to minimize the cost of the
operation.  Like the previous coding, no indexes are opened as long as
at least one insert or update of pg_statistic has happened.

Author: Ranier Vilela
Reviewed-by: Kyotaro Horiguchi, Michael Paquier
Discussion: https://postgr.es/m/CAEudQAqh0F9y6Di_Wc8xW4zkWm_5SDd-nRfVsCn=h0Nm1C_mrg@mail.gmail.com
2022-11-16 10:49:05 +09:00
2022-11-13 09:02:41 +01:00
2022-01-07 19:04:57 -05:00
2020-02-10 20:47:50 +01:00
2020-02-10 20:47:50 +01:00
2020-02-10 20:47:50 +01:00

PostgreSQL Database Management System
=====================================

This directory contains the source code distribution of the PostgreSQL
database management system.

PostgreSQL is an advanced object-relational database management system
that supports an extended subset of the SQL standard, including
transactions, foreign keys, subqueries, triggers, user-defined types
and functions.  This distribution also contains C language bindings.

PostgreSQL has many language interfaces, many of which are listed here:

	https://www.postgresql.org/download/

See the file INSTALL for instructions on how to build and install
PostgreSQL.  That file also lists supported operating systems and
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system.  Copyright and license information can be found in the
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instructions.

The latest version of this software may be obtained at
https://www.postgresql.org/download/.  For more information look at our
web site located at https://www.postgresql.org/.
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