You can optionally cluster a table based on index order with PostgreSQL, simply create the index and then `ALTER TABLE foo CLUSTER ON bar_ix`. Clustered indexes are actually an issue I run into with SQL server, because, like MySQL, the table data is always indirectly referenced by the clustered index, so any query that uses a secondary index requires a second pointer deref to find the data in the table heap. This has a benefit to insert/update performance, but I'd argue that more tables are higher on reads than mutations.