diff options
| author | Heikki Linnakangas <heikki.linnakangas@iki.fi> | 2014-11-06 13:52:08 +0200 |
|---|---|---|
| committer | Heikki Linnakangas <heikki.linnakangas@iki.fi> | 2014-11-06 13:55:36 +0200 |
| commit | 2076db2aea766c4c828dccc34ae35f614129000d (patch) | |
| tree | 5004b943d2014fdf3c2d4bed820fe550c5013c96 /doc/src/sgml | |
| parent | d2b8a2c7ec1098e7b98160ccdc0e3a513964fb08 (diff) | |
Move the backup-block logic from XLogInsert to a new file, xloginsert.c.
xlog.c is huge, this makes it a little bit smaller, which is nice. Functions
related to putting together the WAL record are in xloginsert.c, and the
lower level stuff for managing WAL buffers and such are in xlog.c.
Also move the definition of XLogRecord to a separate header file. This
causes churn in the #includes of all the files that write WAL records, and
redo routines, but it avoids pulling in xlog.h into most places.
Reviewed by Michael Paquier, Alvaro Herrera, Andres Freund and Amit Kapila.
Diffstat (limited to 'doc/src/sgml')
| -rw-r--r-- | doc/src/sgml/wal.sgml | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/doc/src/sgml/wal.sgml b/doc/src/sgml/wal.sgml index 0420610a011..6172a087f2f 100644 --- a/doc/src/sgml/wal.sgml +++ b/doc/src/sgml/wal.sgml @@ -578,12 +578,12 @@ <para> There are two commonly used internal <acronym>WAL</acronym> functions: - <function>XLogInsert</function> and <function>XLogFlush</function>. - <function>XLogInsert</function> is used to place a new record into + <function>XLogInsertRecord</function> and <function>XLogFlush</function>. + <function>XLogInsertRecord</function> is used to place a new record into the <acronym>WAL</acronym> buffers in shared memory. If there is no - space for the new record, <function>XLogInsert</function> will have + space for the new record, <function>XLogInsertRecord</function> will have to write (move to kernel cache) a few filled <acronym>WAL</acronym> - buffers. This is undesirable because <function>XLogInsert</function> + buffers. This is undesirable because <function>XLogInsertRecord</function> is used on every database low level modification (for example, row insertion) at a time when an exclusive lock is held on affected data pages, so the operation needs to be as fast as possible. What @@ -594,7 +594,7 @@ made, for the most part, at transaction commit time to ensure that transaction records are flushed to permanent storage. On systems with high log output, <function>XLogFlush</function> requests might - not occur often enough to prevent <function>XLogInsert</function> + not occur often enough to prevent <function>XLogInsertRecord</function> from having to do writes. On such systems one should increase the number of <acronym>WAL</acronym> buffers by modifying the <xref linkend="guc-wal-buffers"> parameter. When @@ -683,7 +683,7 @@ Enabling the <xref linkend="guc-wal-debug"> configuration parameter (provided that <productname>PostgreSQL</productname> has been compiled with support for it) will result in each - <function>XLogInsert</function> and <function>XLogFlush</function> + <function>XLogInsertRecord</function> and <function>XLogFlush</function> <acronym>WAL</acronym> call being logged to the server log. This option might be replaced by a more general mechanism in the future. </para> @@ -708,7 +708,7 @@ building the server). Each segment is divided into pages, normally 8 kB each (this size can be changed via the <option>--with-wal-blocksize</> configure option). The log record headers are described in - <filename>access/xlog.h</filename>; the record content is dependent + <filename>access/xlogrecord.h</filename>; the record content is dependent on the type of event that is being logged. Segment files are given ever-increasing numbers as names, starting at <filename>000000010000000000000000</filename>. The numbers do not wrap, |