Search found 30 matches

by matthewcornell
Fri Mar 28, 2014 2:44 pm
Forum: New to Vertica
Topic: Need Syntax for Hash And Merge Join
Replies: 2
Views: 2288

Re: Need Syntax for Hash And Merge Join

That's an excellent micro tutorial, James. Thanks so much! Some newbie questions, if you have a chance: We have inequalities in our queries. Docs say that these always cause JOIN HASH's. How do you deal with inequalities? Try to refactor the query, I suppose. But what if we don't have that choice? D...
by matthewcornell
Wed Mar 26, 2014 9:36 pm
Forum: Vertica Performance Tuning
Topic: performance of simple query on from-scratch database varies
Replies: 6
Views: 2257

Re: performance of simple query on from-scratch database var

Thanks for giving me something to think about, sKwa. Sorry I didn't include details - I was hoping to get some general information without bogging it down.
by matthewcornell
Wed Mar 26, 2014 8:48 pm
Forum: Vertica Performance Tuning
Topic: performance of simple query on from-scratch database varies
Replies: 6
Views: 2257

Re: performance of simple query on from-scratch database var

I'm very curious about what you mean by prime the caches. While there is some metadata collected, the queries should be freshly compiled each run. I did some more experimenting and got strange results. I ran the same query on 3-node and 4-node database configurations with and without DBD projection...
by matthewcornell
Mon Mar 24, 2014 3:46 pm
Forum: Vertica Performance Tuning
Topic: performance of simple query on from-scratch database varies
Replies: 6
Views: 2257

Re: performance of simple query on from-scratch database var

I made a beginner mistake: I thought I had run multiple times to prime the caches, but I did not. Results of runs 2+ are consistently faster. Sorry about that. -- matt
by matthewcornell
Fri Mar 21, 2014 4:37 pm
Forum: Vertica Performance Tuning
Topic: performance of simple query on from-scratch database varies
Replies: 6
Views: 2257

performance of simple query on from-scratch database varies

Hi Folks, I've started an experiment on our small 4-node cluster to simulate possible performance gains in adding another node. (A good excuse to learn Vertica along the way :-) To do this I'm running our join-heavy benchmark query on 3 nodes and then again after adding the fourth node. I don't yet ...
by matthewcornell
Fri Mar 14, 2014 7:31 pm
Forum: Vertica Performance Tuning
Topic: slow multi-join query for small database (~120K t
Replies: 9
Views: 3506

Re: slow multi-join query for small database (~120K t

Thanks a TON for all the pointers - I'll have a look. I see what you mean about its being complex. I'm up for it, though :ugeek:
by matthewcornell
Fri Mar 14, 2014 6:49 pm
Forum: Vertica SQL
Topic: I removed a node from the database and now my query runs fas
Replies: 4
Views: 1064

Re: I removed a node from the database and now my query runs

Very much obliged, norbertk. I'll check out your blog too. -- matt

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