Re: [HACKERS] MAX Query length
От | Tom Lane |
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Тема | Re: [HACKERS] MAX Query length |
Дата | |
Msg-id | 6291.932050064@sss.pgh.pa.us обсуждение исходный текст |
Ответ на | Re: [HACKERS] MAX Query length (Tom Lane <tgl@sss.pgh.pa.us>) |
Список | pgsql-hackers |
I wrote: > "Ansley, Michael" <Michael.Ansley@intec.co.za> writes: >> At present, disk blocks are set to 8k. Is it as easy as just adjusting the >> constant to enlarge this? Testing queries larger than 16k with only an 8k >> tuple size could be challenging. > As of 6.5, it's just a matter of adjusting BLCKSZ in include/config.h, > rebuilding, and re-initdb-ing. A further thought on this: if you increase BLCKSZ then at least some of the fixed-size text buffers will get bigger, so it's not clear that you will be stressing things all that hard if you take that route. Might be easier to leave BLCKSZ alone and test with queries that are long and complicated but don't actually require a large tuple size. Some examples: 1. SELECT a,a,a,a,... FROM table; 2. SELECT a FROM table WHERE x = 1 OR x = 2 OR x = 3 OR ...; 3. Hugely complex CREATE TABLE commands (lots of constraints and defaults and indexes, which don't enlarge the size ofan actual tuple of the table). regards, tom lane
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