Re: [HACKERS] xlogfilename - Mailing list pgsql-hackers

From Michael Paquier
Subject Re: [HACKERS] xlogfilename
Date
Msg-id CAB7nPqQ+OJDNFiXuMB-pEZGGUQyf2a6tu3EV7kPQ5Q2=xZ9NAg@mail.gmail.com
Whole thread Raw
In response to Re: [HACKERS] xlogfilename  (DEV_OPS <devops@ww-it.cn>)
Responses Re: [HACKERS] xlogfilename
List pgsql-hackers
On Thu, Jul 20, 2017 at 10:58 AM, DEV_OPS <devops@ww-it.cn> wrote:
> I think you may reference to function: pg_xlogfile_name   in
> src/backend/access/transam/xlogfuncs.c,  it use XLogFileName  defined in
> src/include/access/xlog_internal.h
>
> #define XLogFileName(fname, tli, logSegNo)  \
>     snprintf(fname, MAXFNAMELEN, "%08X%08X%08X", tli,       \
>              (uint32) ((logSegNo) / XLogSegmentsPerXLogId), \
>              (uint32) ((logSegNo) % XLogSegmentsPerXLogId))
>
>
> hope it's helpful for you

The first 8 characters are the timeline number in hexadecimal format.
The next 8 characters indicate a segment number, which gets
incremented every 256 segments in hexa format. The last 8 characters
indicate the current segment number in hexa format.
-- 
Michael



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