Re: Further pg_upgrade analysis for many tables

On Mon, Nov 12, 2012 at 12:09:08PM -0500, Bruce Momjian wrote:
> The second approach would be to simply try to copy the fsm, vm, and
> extent files, and ignore any ENOEXIST errors. This allows code
> simplification. The downside is that it doesn't pull all files with
> matching prefixes --- it requires pg_upgrade to _know_ what suffixes
> might exist in that directory. Second, it assumes there can be no
> number gaps in the file extent numbering (is that safe?).

Seems our code does the same kind of segment number looping I was
suggesting for pg_upgrade, so I think I am safe:

/*
* Note that because we loop until getting ENOENT, we will correctly
* remove all inactive segments as well as active ones.
*/
for (segno = 1;; segno++)
{
sprintf(segpath, "%s.%u", path, segno);
if (unlink(segpath) < 0)
{
/* ENOENT is expected after the last segment... */
if (errno != ENOENT)
ereport(WARNING,
(errcode_for_file_access(),
errmsg("could not remove file \"%s\": %m", segpath)));
break;
}
}

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

+ It's impossible for everything to be true. +