From 2589735da08c4e597accb6eab5ae65b6339ee630 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Sat, 25 Aug 2001 18:52:43 +0000 Subject: Replace implementation of pg_log as a relation accessed through the buffer manager with 'pg_clog', a specialized access method modeled on pg_xlog. This simplifies startup (don't need to play games to open pg_log; among other things, OverrideTransactionSystem goes away), should improve performance a little, and opens the door to recycling commit log space by removing no-longer-needed segments of the commit log. Actual recycling is not there yet, but I felt I should commit this part separately since it'd still be useful if we chose not to do transaction ID wraparound. --- doc/src/sgml/backup.sgml | 8 ++++---- doc/src/sgml/wal.sgml | 8 ++++---- 2 files changed, 8 insertions(+), 8 deletions(-) (limited to 'doc/src') diff --git a/doc/src/sgml/backup.sgml b/doc/src/sgml/backup.sgml index feefc2baef4..cb81d4a08b7 100644 --- a/doc/src/sgml/backup.sgml +++ b/doc/src/sgml/backup.sgml @@ -1,4 +1,4 @@ - + Backup and Restore @@ -339,11 +339,11 @@ tar -cf backup.tar /usr/local/pgsql/data individual tables or databases from their respective files or directories. This will not work because the information contained in these files contains only half the - truth. The other half is in the file - pg_log, which contains the commit status of + truth. The other half is in the commit log files + pg_clog/*, which contain the commit status of all transactions. A table file is only usable with this information. Of course it is also impossible to restore only a - table and the associated pg_log file + table and the associated pg_clog data because that will render all other tables in the database cluster useless. diff --git a/doc/src/sgml/wal.sgml b/doc/src/sgml/wal.sgml index 602ed11f974..91c570f0a2d 100644 --- a/doc/src/sgml/wal.sgml +++ b/doc/src/sgml/wal.sgml @@ -1,4 +1,4 @@ - + Write-Ahead Logging (<acronym>WAL</acronym>) @@ -83,12 +83,12 @@ In this first release of WAL, UNDO operation is not implemented, because of lack of time. This means that changes made by aborted transactions will still occupy disk space and that - we still need a permanent pg_log file to hold + we still need a permanent pg_clog file to hold the status of transactions, since we are not able to re-use transaction identifiers. Once UNDO is implemented, - pg_log will no longer be required to be + pg_clog will no longer be required to be permanent; it will be possible to remove - pg_log at shutdown, split it into segments + pg_clog at shutdown, split it into segments and remove old segments. -- cgit v1.2.3