Coming from the MSSQL world, I'm used to the first step in optimization
to be, choose your clustered index and choose it well.
I see that PG has a one-shot CLUSTER command, but doesn't support
continuously-updated clustered indexes.
What I infer from newsgroup browsing is, such an index is impossible,
given the MVCC versioning of records (happy to learn I'm wrong).
I'd be curious to know what other people, who've crossed this same
bridge from MSSQL or Oracle or Sybase to PG, have devised,
faced with the same kind of desired performance gain for retrieving
blocks of rows with the same partial key.
