## E.201. Release 9.0.17

Release date: 2014-03-20

This release contains a variety of fixes from 9.0.16. For information about new features in the 9.0 major release, see Section E.218.

### E.201.1. Migration to Version 9.0.17

A dump/restore is not required for those running 9.0.X.

However, if you are upgrading from a version earlier than 9.0.15, see Section E.203.

### E.201.2. Changes

- Restore GIN metapages unconditionally to avoid torn-page risk (Heikki Linnakangas)

  Although this oversight could theoretically result in a corrupted index, it is unlikely to have caused any problems in practice, since the active part of a GIN metapage is smaller than a standard 512-byte disk sector.

- Avoid race condition in checking transaction commit status during receipt of a `NOTIFY` message (Marko Tiikkaja)

  This prevents a scenario wherein a sufficiently fast client might respond to a notification before database updates made by the notifier have become visible to the recipient.

- Allow regular-expression operators to be terminated early by query cancel requests (Tom Lane)

  This prevents scenarios wherein a pathological regular expression could lock up a server process uninterruptibly for a long time.

- Remove incorrect code that tried to allow `OVERLAPS` with single-element row arguments (Joshua Yanovski)

  This code never worked correctly, and since the case is neither specified by the SQL standard nor documented, it seemed better to remove it than fix it.

- Avoid getting more than `AccessShareLock` when de-parsing a rule or view (Dean Rasheed)

  This oversight resulted in pg_dump unexpectedly acquiring `RowExclusiveLock` locks on tables mentioned as the targets of `INSERT`/`UPDATE`/`DELETE` commands in rules. While usually harmless, that could interfere with concurrent transactions that tried to acquire, for example, `ShareLock` on those tables.

- Improve performance of index endpoint probes during planning (Tom Lane)

  This change fixes a significant performance problem that occurred when there were many not-yet-committed rows at the end of the index, which is a common situation for indexes on sequentially-assigned values such as timestamps or sequence-generated identifiers.

- Fix test to see if hot standby connections can be allowed immediately after a crash (Heikki Linnakangas)

- Prevent interrupts while reporting non-`ERROR` messages (Tom Lane)

  This guards against rare server-process freezeups due to recursive entry to `syslog()`, and perhaps other related problems.

- Prevent intermittent “could not reserve shared memory region” failures on recent Windows versions (MauMau)

- Update time zone data files to tzdata release 2014a for DST law changes in Fiji and Turkey, plus historical changes in Israel and Ukraine.