pg_stat_activity is system view that shows what is currently happening in the DB.
With newer pgs it's rather wide (22 columns as I write this). And, it's not always obvious what all this means. So let's try to figure it out.
Autovacuum was added LONG time ago (in 7.4, as pg_autovacuum). Since then, there were many changes related to it.
These days, hopefully, we no longer see someone saying that they have to disable autovacuum due to performance issues.
But I still see people that say that they have to run daily/weekly vacuum because “autovacuum is not enough". Is it really?
While there are some docs on it, I decided to write about it, in perhaps more accessible language – not as a developer, but as PostgreSQL user.
Some parts (quite large parts) were described in one of my earlier posts, but I'll try to concentrate on WAL itself, and show a bit more in here.
For todays post in Understanding postgresql.conf series, I chose work_mem parameter.
Starting new blog series – explanation of various configuration parameters.
I will of course follow no schedule or order – if I'd had to – it would be my job, and in this way – it's fun.
First configuration parameter to write about is checkpoint_completion_target.