Inspired by Charles' thread and the work of Emmanuel [1], I have made some experiments trying to create a trigger to make partitioning using C language.
The first attempt was not good, I tried to use SPI [2] to create a query to insert into the correct child table, but it took almost no improvement compared with the PL/pgSQL code.
The right way to do this with SPI is to prepare each insert-statement on first invocation (SPI_prepare + SPI_keepplan), and reuse the plan after that (SPI_execute_with_args).
If you construct and plan the query on every invocation, it's not surprising that it's no different from PL/pgSQL performance.
Yeah. I thought about that, but the problem was that I assumed the INSERTs came with random date, so in the worst scenario I would have to keep the plans of all of the child partitions. Am I wrong?
But thinking better, even with hundreds of partitions, it wouldn't use to much memory/resource, would it?
In fact, I didn't give to much attention to SPI method, because the other one is where we can have more fun, =P.
Anyway, I'll change the code (maybe now), and see if it gets closer to the other method (that uses heap_insert), and will post back the results here.
Interesting that you got an improvement. In my case I get almost no improvement at all:
PL/SQL – Dynamic Trigger
4:15:54
PL/SQL - CASE / WHEN Statements
4:12:29
PL/SQL - IF Statements
4:12:39
C Trigger
4:10:49
Here is my code, I’m using heap insert and updating the indexes. With a similar approach of yours.
Humm... Looking at your code, I saw no big difference from mine. The only thing I saw is that you don't fire triggers, but it would be even faster this way. Another thing that could cause that is the number of partitions, I tried only with 12.
Could you make a test suite? Or try to run with my function in your scenario? It would be easy to make it get the partitions by day [1].
