I am trying to understand the heap_blks_read and heap_blks_hit of pg_statio_all_tables in 9.2
Do the numbers refer only to SELECT, or they take INSERT into account?
Would a heap_blks_read / ( heap_blks_read + heap_blks_hit ) ration of over 55% combined with a heap_blks_read value of over 50M indicate an issue with the queries affecting that table, or it is normal if the table is heavily written to?