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Re: PostgreSQL cursors with Perl.

by ctilmes (Vicar)
on Apr 17, 2008 at 13:46 UTC ( #681157=note: print w/replies, xml ) Need Help??

in reply to PostgreSQL cursors with Perl.

I used to keep it in plaintext files, but now I'd want to run some simple queries with it. Hence, I need a database.

What type of queries? What type of data structures/schema are you using?

FWIW, I've found BerkelyDB very nice for simple data structures, and very fast local queries. (I also find PostgreSQL very nice for more complicated data structures and queries...)

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Re^2: PostgreSQL cursors with Perl.
by atemerev (Beadle) on Apr 17, 2008 at 14:02 UTC

    I have quotes data for around 15 currency pairs (like 'EUR/USD', 'USD/JPY' etc). For every currency pair there is a separate table (there are no inter-table joins) of a following structure:

    id => int primary key, timestamp => bigint, # epoch timestamp in milliseconds bid => decimal, ask => decimal, bid_amount => int, ask_amount => int, data => varchar # lots of additional data that # need not to be indexed nor normalized

    The queries look like:

    SELECT * FROM table WHERE timestamp > ? AND timestamp < ?


    SELECT MAX(bid), MIN(bid), MAX(ask), MIN(ask) FROM table WHERE timestamp > ? AND timestamp < ?
Re^2: PostgreSQL cursors with Perl.
by camlet (Novice) on Apr 17, 2008 at 20:41 UTC
    i don't know if sec will work for 15 gig files but sec works very efficiently with monitoring and parsing simultaneously a large amount of log files. hth.
      Thanks for link. Probably I will not use it for this particular task, but this thing definitely is worth looking at.

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[Eily]: well, at least it's right about warn doing the same thing as die :)
[shmem]: same with undef as last element
[msh210]: oh, good point. It's the best kind of correct
[shmem]: msh210: but I'd not call it a lie outright. That's when you do know the truth.
[msh210]: I don't have sendmail (I'm on MS Windows), so does one of you think you can report the bug?
[shmem]: msh210: 'tis about time to tell the sad truth to perl5porters - via perlbug
[msh210]: probably whoever wrote that actually knows the truth
[shmem]: msh210: you can save the perlbug text in a file and send that via your mail agent of choice
[msh210]: hm, okay, I'll try, thanks
[shmem]: ...not as an attachment, it's probably better to c&p that into the mail body

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