Re: Can we get rid of repeated queries from pg_dump?

Stephen Frost <sfrost(at)snowman(dot)net> writes:
> * Tom Lane (tgl(at)sss(dot)pgh(dot)pa(dot)us) wrote:
>> I experimented with the attached, very quick-n-dirty patch to collect
>> format_type results during the initial scan of pg_type, instead. On the
>> regression database in HEAD, it reduces the number of queries pg_dump
>> issues from 3260 to 2905; but I'm having a hard time detecting any net
>> performance change.

> Seems like the issue here is mainly just the latency of each query being
> rather high compared to most use-cases, so local testing where there's
> basically zero latency wouldn't see any change in timing, but throw a
> trans-atlantic or worse amount of latency between the system running
> pg_dump and the PG server and you'd see notable wall-clock savings in
> time.

Yeah. What I was more concerned about was the potential downside
of running format_type() for each pg_type row, even though we might
use only a few of those results. The fact that I'm *not* seeing
a performance hit with a local server is encouraging from that
standpoint.

regards, tom lane