On Wed, Jul 15, 2020 at 02:49:16PM -0400, Henrique Montenegro wrote: > Any idea why the actual time is in the 3ms range? If I query that partition > directly, like this: > > As you can see, the `actual_time` when querying the partition table > directly goes to 0.002 which is almost 2000x faster. Because querying parents of 1000s of tables is slow. That's improved in v12. You can read a previous discussion about it here: https://www.postgresql.org/message-id/20200223151038.GW31889@xxxxxxxxxxxxx But I think you need to know more about partitioning. It doesn't magically make things faster for you, and if you just guess, then it's likely to perform worse for reading and/or writing. Partitioning only helps for INSERTs if nearly all the insertions happening at a given time go into a small number of partitions. Like inserting data partitioned by "timestamp", where all the new data goes into a partition for the current date. Otherwise instead of one gigantic index which doesn't fit in shared_buffers or RAM, you have some hundreds of indexes which also don't simultaneously fit into RAM. That doesn't help writes, and hurts planning time. -- Justin
