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slow aggregate multiple columns - 10x slower than J

I'm evaluating kdb against an existing J application and was surprised to see how slow an aggregate of multiple columns is - both in memory and hdbThe application is aggregating approximately 51 million rows down to 13 million customer product combin...

joebo by New Contributor
  • 7 replies
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aj with more than one syms?

If I follow the recommendations on can join trades to partitioned on-disk quotes very quickly if i have`p#sym with something likeq) aj[`sym`time; t; select from q where date 15.01.01]but if I want to use a...

new kdb+ book, Nick Psaris' Q Tips

Nick Psaris has published a book: “Q Tips: Fast, Scalable and Maintainable Kdb+” for programmers immersed in analysing big data in financial services.More details on the website at:

simon1 by New Contributor
  • 8 replies
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This works:q)t:([]a:`a`b;b:0 1;c:"ab")q)show t,:([]a:`c`d;c:"cd")a b c-----a 0 ab 1 bc cd dWhy this, which semantically you'd think it's exactly the same thing, doesn't work?q)t:([]a:`a`b;b:0 1;c:"ab")q)t:t,([]a:`c`d;c:"cd")'mismatch

borota by New Contributor
  • 2 replies
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segmented hdb / 32-bit not enough storage error

I'm receiving the message 'Not enough storage is available to process this command.' when attempting to load a large database with slave processes.I'm attempting to use sub-processes to query a large database on the 32-bit version of kdb. I've modifi...

joebo by New Contributor
  • 1 replies
  • 0 kudos