Re: [HACKERS] Plan stability versus near-exact ties in cost estimates

2012-04-21 Thread Albe Laurenz
Tom Lane wrote: >>> Um, that is what the proposed patch does. >> I was referring to the first two lines that the patch removes. >> I guess I don't understand why they should go. > What we'd have left after the proposed removal is > >if (new_path->rows < old_path->rows)

Re: [HACKERS] RANGE type, and its subtype parameter

2012-04-21 Thread Guillaume Lelarge
On Sat, 2012-04-21 at 07:03 +0530, Amit Kapila wrote: > If I understood correctly the following query should give your answer: > Select opcintype from pg_opclass where opcname = ''; You're right, and my question was wrong. I finally found the SQL query I was looking for. Thanks. -- Guillaume h

[HACKERS] B-tree page deletion boundary cases

2012-04-21 Thread Noah Misch
For the sake of concurrency, our B-tree implementation has a phased process for reusing empty pages. Excerpting from nbtree/README: A deleted page cannot be reclaimed immediately, since there may be other processes waiting to reference it (ie, search processes that just left the

Re: [HACKERS] B-tree page deletion boundary cases

2012-04-21 Thread Nikhil Sontakke
Hi Noah, Was wondering if there's a similar bug which gets triggered while using VACUUM FULL. See for instance this thread: http://postgresql.1045698.n5.nabble.com/index-corruption-in-PG-8-3-13-td4257589.html This issue has been reported on-off from time to time and in most cases VACUUM or VACUU

Re: [HACKERS] RFC: Making TRUNCATE more "MVCC-safe"

2012-04-21 Thread Jeff Davis
On Sun, 2012-03-04 at 16:39 +, Simon Riggs wrote: > >> v3 attached. Added to next commitfest. Regards, Jeff Davis -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers

[HACKERS] 9.3: summary of corruption detection / checksums / CRCs discussion

2012-04-21 Thread Jeff Davis
A lot of discussion took place regarding corruption detection, and I am attempting to summarize it in a useful way. Please excuse the lack of references; I'm hoping to agree on the basic problem space and the nature of the solutions offered, and then turn it into a wiki where we can get into the de

Re: [HACKERS] 9.3: summary of corruption detection / checksums / CRCs discussion

2012-04-21 Thread Greg Stark
On Sat, Apr 21, 2012 at 10:40 PM, Jeff Davis wrote: > * In addition to detecting random garbage, we also need to be able to > detect zeroing of pages. Right now, a zero page is not considered > corrupt, so that's a problem. We'll need to WAL table extension > operations, and we'll need to mitigate

[HACKERS] Re: 9.3: summary of corruption detection / checksums / CRCs discussion

2012-04-21 Thread Jeff Davis
On Sun, 2012-04-22 at 00:08 +0100, Greg Stark wrote: > On Sat, Apr 21, 2012 at 10:40 PM, Jeff Davis wrote: > > * In addition to detecting random garbage, we also need to be able to > > detect zeroing of pages. Right now, a zero page is not considered > > corrupt, so that's a problem. We'll need to