mirror/postgresql
2
0
Fork 0
mirror of https://git.postgresql.org/git/postgresql.git synced 2025-01-12 18:34:36 +08:00
Code Issues Packages Projects Releases Wiki Activity

Add C comment about DDL changes possibly causing pg_dump errors.

Browse Source
This commit is contained in:
Bruce Momjian 2010-03-03 23:38:44 +00:00
parent ea066f87c3
commit 0ea0afa444
1 changed files with 14 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
src/bin/pg_dump/pg_dump.c
View File

@ -11,8 +11,21 @@
* script that reproduces the schema in terms of SQL that is understood
* by PostgreSQL
*
* Note that pg_dump runs in a serializable transaction, so it sees a
* consistent snapshot of the database including system catalogs.
* However, it relies in part on various specialized backend functions
* like pg_get_indexdef(), and those things tend to run on SnapshotNow
* time, ie they look at the currently committed state. So it is
* possible to get 'cache lookup failed' error if someone performs DDL
* changes while a dump is happening. The window for this sort of thing
* is from the beginning of the serializable transaction to
* getSchemaData() (when pg_dump acquires AccessShareLock on every
* table it intends to dump). It isn't very large, but it can happen.
*
* http://archives.postgresql.org/pgsql-bugs/2010-02/msg00187.php
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/bin/pg_dump/pg_dump.c,v 1.576 2010/03/03 20:10:48 heikki Exp $
* $PostgreSQL: pgsql/src/bin/pg_dump/pg_dump.c,v 1.577 2010/03/03 23:38:44 momjian Exp $
*
*-------------------------------------------------------------------------
*/