On Wed, Jul 17, 2019 at 11:41 AM James(王旭) <wangxu@xxxxxxxxx> wrote: > From these results I can tell the route to a table is not even related with the mod function, right? > So It's hard for me to do any kind of guesses... Because it is the wrong function. According to \d+ on a child table and partbounds.c the function called is satisfied_hash_partition: testdb=# select satisfies_hash_partition('153221'::oid, 3, 0, 6521); satisfies_hash_partition -------------------------- t (1 row) testdb=# select satisfies_hash_partition('153221'::oid, 3, 1, 6521); satisfies_hash_partition -------------------------- f (1 row) The first argument is the table id (partitioned one, the root), the second is the reminder, third is the partition table, last is your value. Therefore I suspect you have to iterate on your partition numbers from 0 to x to see if a value fits in that partition, and then extract the table name from that. Hope its clear. Luca