RE: [Patch] Optimize dropping of relation buffers using dlist

From: tsunakawa.takay@fujitsu.com <tsunakawa.takay@fujitsu.com>
> Can you measure the time DropRelFileNodeBuffers()?  You can call
> GetTimestamp() at the beginning and end of the function, and use
> TimestampDifference() to calculate the difference.  Then, for instance,
> elog(WARNING, "time is | %u.%u", sec, usec) at the end of the function.  You
> can use any elog() print format for your convenience to write shell commands to
> filter the lines and sum up the total.

Before doing this, you can also do "VACUUM (truncate off)" to see which of the garbage collection or relation
truncationtakes long time.  The relation truncation processing includes not only DropRelFileNodeBuffers() but also file
truncationand something else, but it's an easy filter. 


Regards
Takayuki Tsunakawa