Sent that on pgsql-novice list but did not get any answers yet.
Maybe someone could help me understand here J
Hi all,
I have split a large table (billions of records) into multiple partitions, hoping the access would be faster. I used an ID to make partitions check (check (id >= 100 AND id < 200)…) and created over 80 tables (children) that are now filled with data.
However, after I did it, I read a second time the following sentence in the documentation and started wondering what it actually means … “Constraint exclusion only works when the query's WHERE clause contains constants (or externally supplied parameters)”
I understand that the following query will use constraint exclusion and will run faster…
a- Select * from parent_table where id >=9999; -- using a constant
But how constraint exclusion would react with the following queries …
b- Select * from parent_table where id between 2345 and 6789; -- using a range of ids
c- Select * from parent_table where id in(select ids from anothertable); -- using a list of ids from a select
Since I mostly use queries of type b and c, I am wondering if partitioning the large table was appropriate and if the queries are going to be longer to run…
Thank in advance
Daniel
Doc: http://www.postgresql.org/docs/9.3/static/ddl-partitioning.html
