| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Zdenek Kotala <Zdenek(dot)Kotala(at)Sun(dot)COM> |
| Cc: | Gregory Stark <stark(at)enterprisedb(dot)com>, Simon Riggs <simon(at)2ndquadrant(dot)com>, pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: Page-at-a-time Locking Considerations |
| Date: | 2008-02-06 19:58:07 |
| Message-ID: | 16114.1202327887@sss.pgh.pa.us |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
Zdenek Kotala <Zdenek(dot)Kotala(at)Sun(dot)COM> writes:
> Tom Lane wrote:
>> If you only got 2% out of it, it's not even worth thinking about how to
>> fix the serious bugs that approach would create (primarily, lack of
>> control over when pages can get flushed to disk).
> You can flush a pages by msync() function which writes dirty pages on
> disk. I don't see any other problem.
Then you need to learn more. The side of the problem that is hard to
fix is that sometimes we need to prevent pages from being flushed to
disk until some other data (typically WAL entries) has reached disk.
With mmap'd data we have no control over early writes.
regards, tom lane
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Tom Lane | 2008-02-06 20:01:46 | Re: Why are we waiting? |
| Previous Message | Magnus Hagander | 2008-02-06 19:56:53 | Re: GSSAPI and V2 protocol |