| From: | Jeff Davis <pgsql(at)j-davis(dot)com> |
|---|---|
| To: | Andres Freund <andres(at)anarazel(dot)de> |
| Cc: | pgsql-hackers(at)postgresql(dot)org, Noah Misch <noah(at)leadboat(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Andrew Dunstan <andrew(at)dunslane(dot)net> |
| Subject: | Re: initdb and fsync |
| Date: | 2012-03-14 04:23:03 |
| Message-ID: | 1331698983.6425.108.camel@jdavis |
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| Lists: | pgsql-hackers |
On Tue, 2012-03-13 at 09:42 +0100, Andres Freund wrote:
> for recursively everything in dir:
> posix_fadvise(fd, POSIX_FADV_DONTNEED);
>
> for recursively everything in dir:
> fsync(fd);
Wow, that made a huge difference!
no sync: ~ 1.0s
sync: ~10.0s
fadvise+sync: ~ 1.3s
Patch attached.
Now I feel much better about it. Most people will either have fadvise, a
write cache (rightly or wrongly), or actually need the sync. Those that
have none of those can use -N.
Regards,
Jeff Davis
| Attachment | Content-Type | Size |
|---|---|---|
| initdb-fsync-20120313.patch.gz | application/x-gzip | 2.5 KB |
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