On Tuesday, September 3, 2013, Gregory Haase wrote:
I am working on a date-based partitioning framework and I would really like to have a single function that could be used as trigger for any table that needs to be partitioned by day. I am working in a rails environment, so every table has a created_at datetime field.
I created my generic function:
create or replace function day_partition_insert_trigger()
returns trigger as $$
declare
ins_tbl varchar;
begin
ins_tbl := TG_TABLE_SCHEMA || '.' || TG_TABLE_NAME || '_' || to_char(NEW.created_at,'YYYYMMDD');
execute 'insert into '|| ins_tbl ||' select ($1).*' using NEW;
return null;
end;
$$ language plpgsql;
...
I began to wonder if there would be a performance degradation, so I changed the testdailytwo trigger function the typical if, elsif described in the partitioning documentation and then ran pgbench against both tables.
I noticed that with 7 partitions, the if, elsif was slightly faster (~8%). However, when adding 30 partitions, the if, elsif version became slower. I'd sort of expected this.
Did you try an if, elsif, version structured like a binary search rather than a linear search?
Also, did you try them with a \copy rather than insert in a loop?
Cheers,
Jeff
