Most Postgres (PostgreSQL) users who are familiar with partitioning use the method described in the partitioning documentation. This architecture comes in a fairly standard stack:
One empty base table for structure. At least one child table that inherits the base design. A trigger to redirect inserts based on the partitioning scheme. A constraint on each child table to enforce the partition scheme, and help the planner exclude child partitions from inapplicable queries.
What’s a good table to partition? It’s not always a question with an obvious answer. Most often, size and volume determine whether or not a table should be broken into several chunks. However, there’s also cases where business or architecture considerations might use partitioning to preserve a shared table structure, or drive aggregate analysis over a common core. In Postgres (PostgreSQL), this is even more relevant because of how partitioning is handled through inheritance.
In the next few weeks, I’m going to be pushing a long discussion regarding Postgres (PostgreSQL) table partitioning. I’ve covered it in previous articles, but only regarding basic performance considerations. That’s a very limited view of what partitioning can offer; there’s a lot more variance and background that deserves elucidation.
So for the next few articles, the topic of discussion will be partitioning. There’s not really enough of it, and a lot of the techniques used in the field are effectively pulled straight from the documentation.
We’re finally at the end of the 10-part Postgres (PostgreSQL) performance series I use to initiate new developers into the database world. To that end, we’re going to discuss something that affects everyone at one point or another: index criteria. Or to put it another way:
Why isn’t the database using an index?
It’s a fairly innocuous question, but one that may have a surprising answer: the index was created using erroneous assumptions.
An easy way to give Postgres (PostgreSQL) a performance boost is to judiciously use indexes based on queries observed in the system. For most situations, this is as simple as indexing columns that are referenced frequently in WHERE clauses. Postgres is one of the few database engines that takes this idea even further with partial indexes. Unfortunately as a consequence of insufficient exposure, most DBAs and users are unfamiliar with this extremely powerful functionality.
