PostgreSQL 9.4 has added a new SQL command called ALTER SYSTEM SET, introduced by this commit:
Read more...2014-01-20 03:09:15 +0000
PostgreSQL 9.4 has added a new SQL command called ALTER SYSTEM SET, introduced by this commit:
Read more...2014-01-15 06:49:58 +0000
When scanning a relation with a query with a bitmap heap scan and that the bitmap is not large enough to contain a reference to each tuple individually, bitmap heap scan switches to lossy mode where instead of the tuples relation pages are referenced in the bitmap. Then a Recheck condition on the heap is done to determine on each page which tuples to return, and to determine if a page is exact (tuples in the bitmap) or lossy (need to access to heap). The following commit adds an additional output in EXPLAIN ANALYZE to check the number of lossy and exact pages this bitmap heap scan used.
Read more...2014-01-08 07:52:13 +0000
In PostgreSQL terminology, hint bints are a page-level mechanism implemented to be able to guess the visibility status of a tuple directly at the page level (actually whether the tuple xmin or xmax is committed or aborted), without going though checks in pg_clog and pg_subtrans which are expensive. This is part of the field t_infomask in HeapTupleHeaderData of htup_details.h, a set of bits telling about more or less the tuple status on a page.
Read more...2013-12-25 07:43:49 +0000
Postgres 9.4 has added a new feature allowing to delay WAL replay on standbys or even to delay recovery by a given amount of time. It has been introduced by this commit.
Read more...2013-12-17 07:11:18 +0000
Today’s post presents a small utility that has been added during the latest commit fest of Postgres: the possibility to add some custom information in version stream during a server build. It has been introduced by this commit.
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