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Re^5: Architecture design for full stack development.by erix (Prior) |
on Jun 23, 2017 at 17:06 UTC ( [id://1193389]=note: print w/replies, xml ) | Need Help?? |
CLUSTER [1] rewrites a table in the order of an index (to wit, the index you pass to the CLUSTER command). Access of singular values does not change; but access of values that are now (after CLUSTER) 'near' each other can become faster (because there is a higher chance they are already read). It has to do with /physical/ nearness (or proximity) of the table data, not of the values. At least, that is my theory :) Please don't ask me to submit test results -- I have a system to build! Fair enough :) But I wouldn't undertake any work on the basis of your theory - I don't think it is valid. I'll try to devise a test myself, and see if one of our theories can be falsified.
[1] CLUSTER command (PostgreSQL docs)
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