Re: [HACKERS] Rare corruption of pg_class index

2007-01-04 Thread Greg Sabino Mullane
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Tom Lane replied: >> So as a general rule, the system tables should be considered a special >> case as far as transactional activity? To be more precise, you are saying >> that a system table must be locked in access exclusive mode before any >> chan

Re: [HACKERS] Rare corruption of pg_class index

2007-01-03 Thread Tom Lane
"Greg Sabino Mullane" <[EMAIL PROTECTED]> writes: > So as a general rule, the system tables should be considered a special > case as far as transactional activity? To be more precise, you are saying > that a system table must be locked in access exclusive mode before any > change is made to guarant

Re: [HACKERS] Rare corruption of pg_class index

2007-01-03 Thread Greg Sabino Mullane
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Tom Lane wrote: > No, it's not a violation of ACID. In this case what you are doing is > altering a table's schema without a sufficiently strong lock on the > table, and that's a no-no, whether you would like it to be or not. So as a general rule,

Re: [HACKERS] Rare corruption of pg_class index

2007-01-02 Thread Tom Lane
"Greg Sabino Mullane" <[EMAIL PROTECTED]> writes: > Tom Lane wrote: >> Oh! Duh, that's your issue right there, I'll bet. The problem is that >> relcache-open tries to read the pg_class row under SnapshotNow rules, >> and if there is another xact concurrently modifying the row, it is >> entirely p

Re: [HACKERS] Rare corruption of pg_class index

2007-01-02 Thread Greg Sabino Mullane
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Tom Lane wrote: > Oh! Duh, that's your issue right there, I'll bet. The problem is that > relcache-open tries to read the pg_class row under SnapshotNow rules, > and if there is another xact concurrently modifying the row, it is > entirely possible

Re: [HACKERS] Rare corruption of pg_class index

2006-12-26 Thread Tom Lane
"Greg Sabino Mullane" <[EMAIL PROTECTED]> writes: > Tom Lane wrote: >> Does the mentioned OID actually correspond to the OID of the table it's >> supposed to be opening, or is it wrong? Is anything being done to >> the table schema in parallel? > Yes, it is the correct OID. No, nothing done to th

Re: [HACKERS] Rare corruption of pg_class index

2006-12-20 Thread Alvaro Herrera
Tom Lane wrote: > Alvaro Herrera <[EMAIL PROTECTED]> writes: > > Greg Sabino Mullane wrote: > > It would help if you could get a stack trace at the moment of the > > problem, but I'm not sure how to do that. > > Perhaps insert an abort() call right before the elog(ERROR) > that's reporting this.

Re: [HACKERS] Rare corruption of pg_class index

2006-12-20 Thread Greg Sabino Mullane
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 (Jeff Davis: I've not changed the function, so it's not the plan cache) Tom Lane wrote: > Does the mentioned OID actually correspond to the OID of the table it's > supposed to be opening, or is it wrong? Is anything being done to > the table schema

Re: [HACKERS] Rare corruption of pg_class index

2006-12-20 Thread Tom Lane
Alvaro Herrera <[EMAIL PROTECTED]> writes: > Greg Sabino Mullane wrote: >> I'm encountering some disconcerting problems on a 8.1.3 database. >> Very occasionally, I get a "could not open relation with OID xxx". Does the mentioned OID actually correspond to the OID of the table it's supposed to be

Re: [HACKERS] Rare corruption of pg_class index

2006-12-20 Thread Alvaro Herrera
Greg Sabino Mullane wrote: > I'm encountering some disconcerting problems on a 8.1.3 database. > Very occasionally, I get a "could not open relation with OID xxx". > This always occurs inside of a plpgsql function, and always refers > to a normal, stable table that has not been dropped. The first

Re: [HACKERS] Rare corruption of pg_class index

2006-12-20 Thread Jeff Davis
On Wed, 2006-12-20 at 18:06 +, Greg Sabino Mullane wrote: > -BEGIN PGP SIGNED MESSAGE- > Hash: SHA1 > > > I'm encountering some disconcerting problems on a 8.1.3 database. > Very occasionally, I get a "could not open relation with OID xxx". > This always occurs inside of a plpgsql fun

[HACKERS] Rare corruption of pg_class index

2006-12-20 Thread Greg Sabino Mullane
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 I'm encountering some disconcerting problems on a 8.1.3 database. Very occasionally, I get a "could not open relation with OID xxx". This always occurs inside of a plpgsql function, and always refers to a normal, stable table that has not been droppe