Re: [SQL] RE: [GENERAL] Problem with SELECT on large negative INT4
От | Bruce Momjian |
---|---|
Тема | Re: [SQL] RE: [GENERAL] Problem with SELECT on large negative INT4 |
Дата | |
Msg-id | 200001280531.AAA11561@candle.pha.pa.us обсуждение исходный текст |
Ответ на | Re: [SQL] RE: [GENERAL] Problem with SELECT on large negative INT4 (Tom Lane <tgl@sss.pgh.pa.us>) |
Ответы |
Re: [SQL] RE: [GENERAL] Problem with SELECT on large negative INT4
|
Список | pgsql-sql |
> Actually, if Nicolas' table contains both very large positive and very > large negative integers, then his index could be messed up pretty badly. > What Hiroshi saw (and I missed :-() was that btint4cmp can fail and > return a result of the wrong sign if the difference between two integers > overflows. Since index sorting depends critically on the assumption > that the comparator always returns consistent results (a < b and b < c > must imply a < c, but this can fail if a - c overflows), you could have > an out-of-order index. And then probes into the index could fail to > find items they should find ... which is exactly the complained-of > symptom. > > Hiroshi neglected to mention that you'd probably need to drop and > recreate the index after applying the patch; if it's indeed out of > order, just patching the comparator bug isn't enough to fix it. > Does Hiroshi's patch get applied? -- Bruce Momjian | http://www.op.net/~candle pgman@candle.pha.pa.us | (610) 853-3000 + If your life is a hard drive, | 830 Blythe Avenue + Christ can be your backup. | Drexel Hill, Pennsylvania 19026
В списке pgsql-sql по дате отправления: