I want to make a script that will run postgres in-memory without durability. I read this page: http://www.postgresql.org/docs/9.1/static/non-durability.html But I didn't understand how I can set this parameters in script. Could you please, help me?
Thanks for help!
Most of those parameters, like fsync, can only be set in postgresql.conf. Changes are applied by re-starting PostgreSQL. They apply to the whole database cluster - all the databases in that PostgreSQL install. That's because the databases all share a single postmaster, write-ahead log, and set of shared system tables.
The only parameter listed there that you can set at the SQL level in a script is synchronous_commit. By setting synchronous_commit = 'off' you can say "it's OK to lose this transaction if the database crashes in the next few seconds, just make sure it still applies atomically".
I wrote more on this topic in a previous answer, Optimise PostgreSQL for fast testing.
If you want to set the other params with a script you can do so but you have to do it by opening and modifying postgresql.conf using the script, then re-starting PostgreSQL. Text-processing tools like sed make this kind of job easier.
If you're running a debian based linux distro, you can just do something like:
pg_createcluster -d /dev/shm/mypgcluster 8.4 ramcluster
to create a ram based cluster. Note that you'll have to do:
pg_drop cluster 8.4 ramcluster
and recreate it on reboot etc.
