Something of an odd problem I am having (at least seems so to me):

I have a sizeable arrayref of arrayrefs (about 20000 arrays of about 75 elements: roughly 70MB in memory) which is the result of a fetchall_arrayref call with DBI.

It takes about 2 seconds to retrieve and load the data into memory, and then about 10 seconds(!) to undef the data structure (whether explicitely or just at the end of the script). This slowdown seems to be quite consistent - an early iteration of this script was using 10-20 of such data structures, so after it finished all the actual work, it would just sit there for 5-10 minutes before exiting - quite annoying.

One thing I noticed while playing with it is that if I undef the structure and then populate it again (from the same query in fact), the second undef is then instanteneous, or close to it.

This is all on RedHat Linux with perl 5.8.4

Can anyone shed some light on what exactly is going on?

In reply to undef quite slow? by glwtta

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