Re: [HACKERS] Checkpointing problem with new buffer mgr.

2005-06-20 Thread Josh Berkus
Tom, The latest omit-the-hole change went in 2005-06-06 16:22 (EDT), so anything older than that is probably not representative. Looks like this was 5/29. Re-running the tests with current CVS now. -- Josh Berkus Aglio Database Solutions San Francisco ---(end of

Re: [HACKERS] Checkpointing problem with new buffer mgr.

2005-06-19 Thread Josh Berkus
Tom, (I assume this *is* CVS tip, or near to it? The recent CRC32 and omit-the-hole changes should affect the costs of this quite a bit.) It was a recent build. When was CRC32 checked in? -- Josh Berkus Aglio Database Solutions San Francisco ---(end of

Re: [HACKERS] Checkpointing problem with new buffer mgr.

2005-06-19 Thread Tom Lane
Josh Berkus josh@agliodbs.com writes: (I assume this *is* CVS tip, or near to it? The recent CRC32 and omit-the-hole changes should affect the costs of this quite a bit.) It was a recent build. When was CRC32 checked in? The latest omit-the-hole change went in 2005-06-06 16:22 (EDT), so

Re: [HACKERS] Checkpointing problem with new buffer mgr.

2005-06-19 Thread Ron Mayer
Tom Lane wrote: Hm, notice that the processor utilization doesn't actually drop all that much, so it seems it's not fundamentally an I/O storm kind of issue. If I read the chart on the bottom of Josh's links correctly, it looks to me like the fast one is spending 50% CPU in user and 30% CPU

Re: [HACKERS] Checkpointing problem with new buffer mgr.

2005-06-19 Thread Michael Paesold
Tom Lane wrote: Josh Berkus josh@agliodbs.com writes: (I assume this *is* CVS tip, or near to it? The recent CRC32 and omit-the-hole changes should affect the costs of this quite a bit.) It was a recent build. When was CRC32 checked in? The latest omit-the-hole change went in

[HACKERS] Checkpointing problem with new buffer mgr.

2005-06-18 Thread Josh Berkus
Tom, folks, I'm continuing to see a problem with checkpointing and clock-sweep. Previously I thought that it was just the long checkpoint intervals on the standard DBT2 test, but things get worse when you checkpoint more frequently: 60 minute checkpoint:

Re: [HACKERS] Checkpointing problem with new buffer mgr.

2005-06-18 Thread Tom Lane
Josh Berkus josh@agliodbs.com writes: So this is obviously a major performance problem. It could be fixed by turning off checkpointing completely, but I don't think that's really feasable. Any clue on why clock-sweep should be so slammed by checkpoints? Hm, notice that the processor