jm + collation   2

glibc changed their UTF-8 character collation ordering across versions, breaking postgres
This is terrifying:
Streaming replicas—and by extension, base backups—can become dangerously broken when the source and target machines run slightly different versions of glibc. Particularly, differences in strcoll and strcoll_l leave "corrupt" indexes on the slave. These indexes are sorted out of order with respect to the strcoll running on the slave. Because postgres is unaware of the discrepancy is uses these "corrupt" indexes to perform merge joins; merges rely heavily on the assumption that the indexes are sorted and this causes all the results of the join past the first poison pill entry to not be returned. Additionally, if the slave becomes master, the "corrupt" indexes will in cases be unable to enforce uniqueness, but quietly allow duplicate values.


Moral of the story -- keep your libc versions in sync across storage replication sets!
postgresql  scary  ops  glibc  collation  utf-8  characters  indexing  sorting  replicas  postgres 
6 weeks ago by jm
Humblog - Philip Kirwan Ripped Off My iPhone App Content
ouch, nasty allegations. Strikes me that there's a chicken/egg problem: scraping the Dublin Bus website to build a database which you then sell as part of a commercial iPhone app is probably pretty shaky ground to start with
ip  databases  collation  collections  dublin-bus  iphone  apps  scraping  from delicious
january 2010 by jm

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