вт, 20 окт. 2020 г. в 16:50, Mats Olsen <mats@xxxxxxxxxxxxxxxxx>:
On 10/20/20 3:04 PM, Victor Yegorov wrote:
вт, 20 окт. 2020 г. в 11:38, Mats Julian Olsen <mats@xxxxxxxxxxxxxxxxx>:
I'm looking for some help to manage queries against two large tables.
Can you tell the version you're running currently and the output of this query, please?
select name,setting,source from pg_settings where source not in ('default','override');
Running "PostgreSQL 12.2 (Ubuntu 12.2-2.pgdg19.10+1) on x86_64-pc-linux-gnu, compiled by gcc (Ubuntu 9.2.1-9ubuntu2) 9.2.1 20191008, 64-bit"
Updated the gist to include the results forom pg_settings. Here's the direct link https://gist.githubusercontent.com/mewwts/9f11ae5e6a5951593b8999559f5418cf/raw/e5deebbbb48680e04570bec4e9a816fa009da34f/pg_settings
It looks like indexes currently chosen by the planner don't quite fit your query.
I would create the following index (if it's possible to update schema):
ON "uniswap_v2.Pair_evt_Mint" (evt_tx_hash, evt_block_time)
ON "uniswap_v2.Pair_evt_Mint" (evt_tx_hash, evt_block_time)
Same for the second table, looks like
ON "ethereum.transactions" (hash, block_time)
is a better fit for your query. In fact, I do not think `transactions_block_number_time` index is used frequently, 'cos second column of the index is a partitioning key.
Currently planner wants to go via indexes 'cos you've made random access really cheap compared to sequential one (and your findings shows this).
Perhaps on a NVMe disks this could work, but in your case you need to find the real bottleneck (therefore I asked for buffers).
ON "ethereum.transactions" (hash, block_time)
is a better fit for your query. In fact, I do not think `transactions_block_number_time` index is used frequently, 'cos second column of the index is a partitioning key.
Currently planner wants to go via indexes 'cos you've made random access really cheap compared to sequential one (and your findings shows this).
Perhaps on a NVMe disks this could work, but in your case you need to find the real bottleneck (therefore I asked for buffers).
I would set `random_page_cost` to a 2.5 at least with your numbers. Also, I would check DB and indexes for bloat (just a guess now, 'cos your plans miss buffers figures).
Victor Yegorov
