Re: No merge sort?
| От | Taral |
|---|---|
| Тема | Re: No merge sort? |
| Дата | |
| Msg-id | 20030315040703.GA3313@taral.net обсуждение исходный текст |
| Ответ на | Re: No merge sort? (Tom Lane <tgl@sss.pgh.pa.us>) |
| Список | pgsql-hackers |
On Fri, Mar 14, 2003 at 10:43:30PM -0500, Tom Lane wrote: > Sure. That's why we have a planner that distinguishes between startup > cost and total cost, and interpolates when a LIMIT is involved. But > if this mergesort idea only helps for small-limit cases, that's another > restriction on its scope of usefulness... I don't think so, since even in the non-limit case it avoids having to do a full sort if the number of initial streams is finite and small (as in the case I demonstrated), reducing time complexity to O(N). -- Taral <taral@taral.net> This message is digitally signed. Please PGP encrypt mail to me. "Most parents have better things to do with their time than take care of their children." -- Me
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