pgsql/ ontrib/pg_resetxlog/pg_resetxlog.c rc/b ...

CVSROOT: /home/projects/pgsql/cvsroot
Module name: pgsql
Changes by: tgl(at)hub(dot)org 01/07/18 22:12:35

Modified files:
contrib/pg_resetxlog: pg_resetxlog.c
src/backend/access/transam: xlog.c
src/include/access: xlog.h

Log message:
Arrange to recycle old XLOG log segment files as new segment files,
rather than deleting them only to have to create more. Steady state
is 2*CHECKPOINT_SEGMENTS + WAL_FILES + 1 segment files, which will
simply be renamed rather than constantly deleted and recreated.
To make this safe, added current XLOG file/offset number to page
header of XLOG pages, so that an un-overwritten page from an old
incarnation of a logfile can be reliably told from a valid page.
This change means that if you try to restart postmaster in a CVS-tip
database after installing the change, you'll get a complaint about
bad XLOG page magic number. If you don't want to initdb, run
contrib/pg_resetxlog (and be sure you shut down the old postmaster
cleanly).