Re: pg_stat_statements cluttered with "DEALLOCATE dbdpg_p*"

Hello devs,

> I noticed that my pg_stat_statements is cluttered with hundreds of entries 
> like "DEALLOCATE dbdpg_p123456_7", occuring each only once.

Here is a patch and sql test file to:

* normalize DEALLOCATE utility statements in pg_stat_statements

Some drivers such as DBD:Pg generate process/counter-based identifiers for 
PREPARE, which result in hundreds of DEALLOCATE being tracked, although 
the prepared query may be the same. This is also consistent with the 
corresponding PREPARE not being tracked (although the underlying prepared 
query *is* tracked).


** Note **: another simpler option would be to skip deallocates altogether 
by inserting a "&& !IsA(parsetree, DeallocateStmt)" at the beginning of 
pgss_ProcessUtility(). I'm not sure what is best.

-- 
Fabien.