Hello!
We are moving from 10 to 15 and are in testing now.
Our development database is about 1400G and takes 12 minutes to
complete a pg_upgrade with the -k (hard-links) version. This is
on a CentOS 7 server with 80 cores.
Adding -j 40 to use half of those cores also finishes in 12
minutes and ps / top/ htop never show more than a single process
at a time in use.
Bumping that to -j 80 to use them all also finishes in 12 minutes
and still only a single process.
Running the suggested vacuum analyze after pg_upgrade completes
takes about 19 minutes. Adding -j 40 takes that time down to
around 5 minutes, jumps the server load up over 30 and htop shows
40 processes.
If -j 40 helps there--why not with pg_upgrade?
The full commands we are using for pg_upgrade are pretty stock:
time /usr/pgsql-15/bin/pg_upgrade -b /usr/pgsql-10/bin/ -B
/usr/pgsql-15/bin/ -d /var/lib/pgsql/10/data -D
/var/lib/pgsql/15up -k
time /usr/pgsql-15/bin/pg_upgrade -b /usr/pgsql-10/bin/ -B
/usr/pgsql-15/bin/ -d /var/lib/pgsql/10/data -D
/var/lib/pgsql/15up -k -j 40
time /usr/pgsql-15/bin/pg_upgrade -b /usr/pgsql-10/bin/ -B
/usr/pgsql-15/bin/ -d /var/lib/pgsql/10/data -D
/var/lib/pgsql/15up -k -j 80
Our production database is closer to 1900G. If we're looking at a
30 minute pg_upgrade window we'll be okay but if there is anything
we can do to knock that time down we will and any suggestions to
do so would be greatly appreciated.
Jeff Ross
