2013-02-22 01:47:46 +0000
Up to Postgres 9.2, the only foreign data wrapper present in core was file_fdw, allowing you to query files as remote tables. This has been corrected with the addition of a second foreign data wrapper called postgres_fdw. This one simply allows to query foreign Postgres servers and fetch results directly on your local server. It has been introduced by this commit.
Read more...2013-02-19 00:25:55 +0000
pageinspect is an extension module of PostgreSQL core allowing to have a look at the contents of relations (index or table) in the database at a low level. In the case of PostgreSQL, tuples of a table are stored in blocks of data whose size can be changed with –with-blocksize at configure step. This module is particularly useful for debugging when implementing a new functionality that changes visibility of data like what could do an autovacuum or map visibility feature, or simply to understand the internals of Postgres without having to read much codea .
Read more...2013-02-12 08:12:07 +0000
Based on my previous experience using custom background workers (new feature of PostgreSQL 9.3), here is more detailed example of bgworker doing a simple “Hello World” in the server logs.
Read more...2013-02-03 06:23:00 +0000
PostgreSQL 9.3 adds a new feature related to monitoring with the commit below.
Read more...2013-01-29 02:59:59 +0000
Prior to PostgreSQL 9.3, there are two levels of locks allowing to control DML operations on a given set of rows for a transaction by using SELECT FOR SHARE and FOR UPDATE. Such locks taken on rows in a transaction block allow blocking INSERT/DELETE/UPDATE on those rows. There is also a protocol between those lock levels. FOR UPDATE is equivalent to an exclusive lock on the row selected, meaning that no other backend can take a FOR UPDATE lock on the same row and waits until the other other transaction finishes. FOR SHARE means that all the other backends can take a FOR SHARE lock on those rows. No FOR UPDATE locks can be taken on rows already locked with FOR SHARE. It is also possible to use the NOWAIT option, making the server return an error if there is a wait situation.
Read more...Unless otherwise specified, the contents of this website are (C)Copyright Michael Paquier 2010-2023 and are licensed for use under CC BY-SA 3.0.