I'm running PG 9.3.4 on CentOS 6.4 and noted that backing up my database
takes much longer than restoring it.
That seems counter-intuitive to me because it seems like reading from a
database should generally be faster than writing to it.
I have a database that pg_database_size reports as 18GB, and resulting
dump is about 13GB in 27 files (split creates them as 512MB).
A pg_dump backup -- with most of the data stored as large objects --
takes about 5 hours.
But restoring that dump takes about 2 hours. So it's taking 2.5 times
longer to back it up than to restore it.
My backup script runs vacuumlo, then vacuum, then analyze, then pg_dump
--format=c --oids $DB
I actually push pg_dump output through gzip, gpg and split on 512MB
files, but they shouldn't matter too much I figure as I have to run cat,
gpg and gunzip before pg_restore. In fact, my restore should have been
at a disadvantage because I used '-v' and showed the results to my ssh
term over the Internet which includes a line for each LOID, and the
postgresql.conf had 'ddl' logging on (which I suspect I can turn off in
future restores to speed things up a bit).
Is there something that might be wrong about my configuration that the
backup is slower than the restore?
Thanks,
David
