Marc Philipp <mail(at)marcphilipp(dot)de> writes:
> A few performance issues using PostgreSQL's arrays led us to the
> question how postgres actually stores variable length arrays. First,
> let me explain our situation.
> We have a rather large table containing a simple integer primary key
> and a couple more columns of fixed size. However, there is a dates
> column of type "timestamp without time zone[]" that is apparently
> causing some severe performance problems.
How large are the arrays? PG is definitely not designed to do well with
very large arrays (say more than a couple hundred elements). You should
reconsider your data design if you find yourself trying to do that.
regards, tom lane