Thread
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Re: [HACKERS] strange behavior of UPDATE
Edmund Mergl <e.mergl@bawue.de> — 1999-05-25T21:31:37Z
Tom Lane wrote: > > Edmund Mergl <E.Mergl@bawue.de> writes: > > Some more numbers: > > > database #rows inserts create make_sqs make_nqs > > index selects updates > > ---------------------------------------------------------------------------- > > pgsql 10.000 00:24 00:09 00:16 00:25 > > pgsql 100.000 04:01 01:29 01:06 49:45 > > pgsql 1.000.000 39:24 20:49 23:42 ??? > > > whereas the increase of elapsed time is somewhat proportional > > to the number of rows, for the update-case it is rather > > exponential. > > Those are attention-getting numbers, all right. I think that the two > equal-key problems I found last night might partially explain them; > I suspect there are more that I have not found, too. I will look into > it some more. > > Could you try the same queries with no indexes in place, and see what > the time scaling is like then? That would confirm or deny the theory > that it's an index-update problem. here they are, and yes, I double-checked them twice ! database #rows inserts create make_sqs make_nqs index selects updates ---------------------------------------------------------------------------- pgsql 10.000 00:24 - 00:13 00:05 pgsql 100.000 04:01 - 00:83 00:32 pgsql 1.000.000 39:24 - 26:36 26:52 > > Question for the hackers list: are we prepared to install purely > performance-related bug fixes at this late stage of the 6.5 beta cycle? > Bad as the above numbers are, I hesitate to twiddle the btree code and > risk breaking things with only a week of testing time to go... > > regards, tom lane if there is anything else I can do, just let me know. Edmund -- Edmund Mergl mailto:E.Mergl@bawue.de Im Haldenhau 9 http://www.bawue.de/~mergl 70565 Stuttgart fon: +49 711 747503 Germany