| From: | Peter Geoghegan <pg(at)heroku(dot)com> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Jim Nasby <jim(at)nasby(dot)net>, Robert Haas <robertmhaas(at)gmail(dot)com>, Andres Freund <andres(at)2ndquadrant(dot)com>, Merlin Moncure <mmoncure(at)gmail(dot)com>, Pg Hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Clock sweep not caching enough B-Tree leaf pages? |
| Date: | 2014-04-22 00:59:34 |
| Message-ID: | CAM3SWZSdfy1U9MAtPVEnDPuvghgBJoQEnk+3kpAhQ13=+A_fyg@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Mon, Apr 21, 2014 at 5:50 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> ARC *was* the predecessor algorithm. See commit 5d5087363.
I believe that the main impetus for replacing ARC with clock sweep
came from patent issues, though. It was a happy coincidence that clock
sweep happened to be better than ARC, but that doesn't mean that ARC
didn't have some clear advantages, even if it wasn't worth it on
balance. LRU-K, and 2Q have roughly the same advantages. I'm
reasonably confident you can have the best of both worlds, or
something closer to it.
--
Peter Geoghegan
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