Thread: Re: [BUGS] Re: Missing rows with index scan when collation is not "C" (PostgreSQL 9.5)
Re: [BUGS] Re: Missing rows with index scan when collation is not "C" (PostgreSQL 9.5)
From
Peter Geoghegan
Date:
On Wed, Mar 23, 2016 at 10:46 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote: > Robert Haas <robertmhaas@gmail.com> writes: >> Are you still in information-gathering more, or are you going to issue >> a recommendation on how we should proceed here, or what? > > If I had to make a recommendation right now, I would go for your > option #4, ie shut 'em all down Scotty. We do not know the full extent > of the problem but it looks pretty bad, and I think our first priority > has to be to guarantee data integrity. I do not have a lot of faith in > the proposition that glibc's is the only buggy implementation, either. For the record, I have been able to determine by using amcheck on the Heroku platform that en_US.UTF-8 cases are sometimes affected by an inconsistency between strcoll() and strxfrm() behavior, which was previously an open question. I saw only two instances of this across many thousands of servers. For some reason, both cases involved strings with code points from the Arabic alphabet, even though each case was from a totally unrelated customer database. I'll go update the Wiki page for this [1] now. [1] https://wiki.postgresql.org/wiki/Abbreviated_keys_glibc_issue -- Peter Geoghegan
Re: Re: [BUGS] Re: Missing rows with index scan when collation is not "C" (PostgreSQL 9.5)
From
Jim Nasby
Date:
On 8/22/16 7:36 PM, Peter Geoghegan wrote: > For some reason, both cases involved > strings with code points from the Arabic alphabet, even though each > case was from a totally unrelated customer database. Do those code points read right to left? Maybe that had an effect? -- Jim Nasby, Data Architect, Blue Treble Consulting, Austin TX Experts in Analytics, Data Architecture and PostgreSQL Data in Trouble? Get it in Treble! http://BlueTreble.com 855-TREBLE2 (855-873-2532) mobile: 512-569-9461