Re: [HACKERS] 16-bit page checksums for 9.2

2011-12-25 Thread Simon Riggs
On Sat, Dec 24, 2011 at 8:06 PM, Greg Stark st...@mit.edu wrote: On Sat, Dec 24, 2011 at 4:06 PM, Simon Riggs si...@2ndquadrant.com wrote: Checksums merely detect a problem, whereas FPWs correct a problem if it happens, but only in crash situations. So this does nothing to remove the need for

Re: [HACKERS] 16-bit page checksums for 9.2

2011-12-25 Thread Kevin Grittner
Simon Riggs wrote: On Sat, Dec 24, 2011 at 8:06 PM, Greg Stark wrote: The problem is that there is no WAL indicating the hint bit change. And if the torn page includes the new checksum but not the new hint bit or vice versa it will be a checksum mismatch. With *just* this patch, true.

Re: [HACKERS] 16-bit page checksums for 9.2

2011-12-25 Thread Martijn van Oosterhout
On Sat, Dec 24, 2011 at 04:01:02PM +, Simon Riggs wrote: On Sat, Dec 24, 2011 at 3:54 PM, Andres Freund and...@anarazel.de wrote: Why don't you use the same tricks as the former patch and copy the buffer, compute the checksum on that, and then write out that copy (you can even do both

Re: [HACKERS] reprise: pretty print viewdefs

2011-12-25 Thread Andrew Dunstan
On 12/24/2011 02:26 PM, Greg Stark wrote: On Thu, Dec 22, 2011 at 5:52 PM, Andrew Dunstanand...@dunslane.net wrote: I've looked at that, and it was discussed a bit previously. It's more complex because it requires that we keep track of (or calculate) where we are on the line, You might try

Re: [HACKERS] 16-bit page checksums for 9.2

2011-12-25 Thread Robert Haas
On Sun, Dec 25, 2011 at 5:08 AM, Simon Riggs si...@2ndquadrant.com wrote: On Sat, Dec 24, 2011 at 8:06 PM, Greg Stark st...@mit.edu wrote: On Sat, Dec 24, 2011 at 4:06 PM, Simon Riggs si...@2ndquadrant.com wrote: Checksums merely detect a problem, whereas FPWs correct a problem if it happens,

Re: [HACKERS] Moving more work outside WALInsertLock

2011-12-25 Thread Robert Haas
On Fri, Dec 23, 2011 at 2:54 PM, Heikki Linnakangas heikki.linnakan...@enterprisedb.com wrote: Sorry. Last minute changes, didn't retest properly.. Here's another attempt. I tried this one out on Nate Boley's system. Looks pretty good. m = master, x = with xloginsert-scale-2 patch.

[HACKERS] Standalone synchronous master

2011-12-25 Thread Alexander Björnhagen
Hi all, I’m new here so maybe someone else already has this in the works ? Anyway, proposed change/patch : Add a new parameter : synchronous_standalone_master = on | off To control whether a master configured with synchronous_commit = on is allowed to stop waiting for standby WAL sync when

Re: [HACKERS] Page Checksums

2011-12-25 Thread Greg Stark
On Mon, Dec 19, 2011 at 7:16 PM, Kevin Grittner kevin.gritt...@wicourts.gov wrote: It seems to me that on a typical production system you would probably have zero or one such page per OS crash Incidentally I don't think this is right. There are really two kinds of torn pages: 1) The kernel vm