database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-05 07:21:24 +03:00
Code Activity

XLogReader general code cleanup

Browse Source 
Some minor tweaks and comment additions, for cleanliness sake and to
avoid having the upcoming timeline-following patch be polluted with
unrelated cleanup.

Extracted from a larger patch by Craig Ringer, reviewed by Andres
Freund, with some additions by myself.
This commit is contained in:
Alvaro Herrera
2016-03-30 18:56:13 -03:00
parent 50861cd683
commit 3b02ea4f07
5 changed files with 86 additions and 30 deletions
Download Patch File Download Diff File Expand all files Collapse all files

21
src/backend/access/transam/xlogutils.c
View File

@ -19,12 +19,11 @@
#include <unistd.h>
#include "miscadmin.h"
#include "access/xlog.h"
#include "access/xlog_internal.h"
#include "access/xlogutils.h"
#include "catalog/catalog.h"
#include "miscadmin.h"
#include "storage/smgr.h"
#include "utils/guc.h"
#include "utils/hsearch.h"
@ -638,8 +637,17 @@ XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum,
}
/*
* TODO: This is duplicate code with pg_xlogdump, similar to walsender.c, but
* we currently don't have the infrastructure (elog!) to share it.
* Read 'count' bytes from WAL into 'buf', starting at location 'startptr'
* in timeline 'tli'.
*
* Will open, and keep open, one WAL segment stored in the static file
* descriptor 'sendFile'. This means if XLogRead is used once, there will
* always be one descriptor left open until the process ends, but never
* more than one.
*
* XXX This is very similar to pg_xlogdump's XLogDumpXLogRead and to XLogRead
* in walsender.c but for small differences (such as lack of elog() in
* frontend). Probably these should be merged at some point.
*/
static void
XLogRead(char *buf, TimeLineID tli, XLogRecPtr startptr, Size count)
@ -648,6 +656,7 @@ XLogRead(char *buf, TimeLineID tli, XLogRecPtr startptr, Size count)
XLogRecPtr recptr;
Size nbytes;
/* state maintained across calls */
static int sendFile = -1;
static XLogSegNo sendSegNo = 0;
static uint32 sendOff = 0;
@ -664,11 +673,11 @@ XLogRead(char *buf, TimeLineID tli, XLogRecPtr startptr, Size count)
startoff = recptr % XLogSegSize;
/* Do we need to switch to a different xlog segment? */
if (sendFile < 0 || !XLByteInSeg(recptr, sendSegNo))
{
char path[MAXPGPATH];
/* Switch to another logfile segment */
if (sendFile >= 0)
close(sendFile);
@ -745,7 +754,7 @@ XLogRead(char *buf, TimeLineID tli, XLogRecPtr startptr, Size count)
* Public because it would likely be very helpful for someone writing another
* output method outside walsender, e.g. in a bgworker.
*
* TODO: The walsender has it's own version of this, but it relies on the
* TODO: The walsender has its own version of this, but it relies on the
* walsender's latch being set whenever WAL is flushed. No such infrastructure
* exists for normal backends, so we have to do a check/sleep/repeat style of
* loop for now.