-------------------------------------------------- From: "Tom Lane" <[EMAIL PROTECTED]> Sent: Monday, January 21, 2008 10:13 PM To: "Sam Mason" <[EMAIL PROTECTED]> Cc: <pgsql-hackers@postgresql.org> Subject: Re: [HACKERS] Polyphase Merge
I agree --- having to read the run back from external storage, only to write it out again with no further useful work done on it, sounds like a guaranteed loser. To make this work you'll need some kind of ju-jitsu rearrangement that logically puts the run where it needs to go without physically moving any data.
I'm not going to write it back with no useful work on it. I should just write them in reverse order during run formation (ju-jitsu couldn't help me in this case) or read them in reverse order while merging (ju-jitsu may help... the point is that I'm not so good in ju-jitsu).
An idea could be managing a list of pointers to runs contained into tapes. Any comment?
regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
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