On Thu, Nov 21, 2013 at 1:43 AM, Tom Lane <t...@sss.pgh.pa.us> wrote:
> Also, it's not that hard to do plug-pull testing to verify that your > system is telling the truth about fsync. This really ought to be part > of acceptance testing for any new DB server. > I've never tried it but I always wondered how easy it was to do. How would you ever know you had tested it enough? The original mail was referencing a problem with syncing *meta* data though. The semantics around meta data syncs are much less clearly specified, in part because file systems traditionally made nearly all meta data operations synchronous. Doing plug-pull testing on Postgres would not test meta data syncing very well since Postgres specifically avoids doing much meta data operations by overwriting existing files and blocks as much as possible. You would have to test doing table extensions or pulling the plug immediately after switching xlog files repeatedly to have any coverage at all there. -- greg
