On Tue, 2009-12-01 at 10:55 -0500, Tom Lane wrote: > Simon Riggs <si...@2ndquadrant.com> writes: > > On Tue, 2009-12-01 at 16:40 +0200, Heikki Linnakangas wrote: > >> It's not hard to imagine that when a hardware glitch happens > >> causing corruption, it also causes the system to crash. Recalculating > >> the CRCs after crash would mask the corruption. > > > They are already masked from us, so continuing to mask those errors > > would not put us in a worse position. > > No, it would just destroy a large part of the argument for why this > is worth doing. "We detect disk errors ... except for ones that happen > during a database crash." "Say what?" > > The fundamental problem with this is the same as it's been all along: > the tradeoff between implementation work expended, performance overhead > added, and net number of real problems detected (with a suitably large > demerit for actually *introducing* problems) just doesn't look > attractive. You can make various compromises that improve one or two of > these factors at the cost of making the others worse, but at the end of > the day I've still not seen a combination that seems worth doing.
Let me try a different but similar perspective. The problem we are trying to solve here, only matters to a very small subset of the people actually using PostgreSQL. Specifically, a percentage that is using PostgreSQL in a situation where they can lose many thousands of dollars per minute or hour should an outage occur. On the other hand it is those very people that are *paying* people to try and implement these features. Kind of a catch-22. The hard core reality is this. *IF* it is one of the goals of this project to insure that the software can be safely, effectively, and responsibly operated in a manner that is acceptable to C* level people in a Fortune level company then we *must* solve this problem. If it is not the goal of the project, leave it to EDB/CMD/2ndQuandrant to fork it because it will eventually happen. Our customers are demanding these features. Sincerely, Joshua D. Drake -- PostgreSQL.org Major Contributor Command Prompt, Inc: http://www.commandprompt.com/ - 503.667.4564 Consulting, Training, Support, Custom Development, Engineering If the world pushes look it in the eye and GRR. Then push back harder. - Salamander -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
