RE: query length limits
От | Ansley, Michael |
---|---|
Тема | RE: query length limits |
Дата | |
Msg-id | 1BF7C7482189D211B03F00805F8527F70ED04E@S-NATH-EXCH2 обсуждение исходный текст |
Список | pgsql-hackers |
Well, this is what I have discovered so far: I left BLCKSZ as it was, but adjusted MAX_QUERY_SIZE to 65535, and ran make. I tried to run a 50k query, and it worked; it took a while, but the results were fine. So, as a temporary solution to this problem, you should be able to set MAX_QUERY_SIZE up to what you require (don't go overboard, and please let me know of any problems). However, make sure that you test it properly first, because I didn't do extensive testing, just enough to make sure that it didn't break immediately. Also, please remember that long queries definitely impact the query processor, so long queries are not a great idea for online sub-systems. They're not great for batch either, but at least there you have a window to play with. More news to come..... MikeA >> > >> > Troy wrote: >> > >> Does Postgres have any limitations on >> > >> the length of queries? >> > >> >> > >> E.g. is "select one,two,three,...thousand from >> one,two,three,...thousand >> > where one = x and two is >> x and three is x and ... >> thousand = x" legal? >> > >> >> > Yes, there is. It is set to BLCKSZ * 2, at least in 6.5. >> BLCKSZ is >> > normally 8192 bytes, so your query size will be 16k. >> However, I'm busy >> > working on it at the moment, to make it unlimited (i.e.: >> limited by memory >> > available). >> > >> > MikeA >> > >> > >>
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