Log message:
Recursive PKGREVISION bump for libxml2 buildlink addition.

Log message:
Changes:
* Fix btree index corruption from insertions concurrent with vacuuming
* Recover from errors occurring during WAL replay of DROP TABLESPACE
* Fix transient zeroing of shared buffers during WAL replay
* Fix postmaster to attempt restart after a hot-standby crash
* Fix corner case in SSI transaction cleanup
* Update per-column permissions, not only per-table permissions, when changing
  table owner
* Fix handling of data-modifying WITH subplans in READ COMMITTED rechecking
* Fix for "could not find plan for CTE" failures
* Fix unsupported node type error caused by COLLATE in an INSERT expression
* Avoid crashing when we have problems deleting table files post-commit
* Fix recently-introduced memory leak in processing of inet/cidr
* Fix GIN cost estimation to handle column IN (...) index conditions
* Fix I/O-conversion-related memory leaks in plpgsql
* Teach pg_upgrade to handle renaming of plpython's shared library (affecting
  upgrades to 9.1)

Log message:
Version 9.1 delivers several features which users have been requesting for
years, removing roadblocks to deploying new or ported applications on
PostgreSQL. These include:
* Synchronous Replication: enable high-availability with consistency across
  multiple servers
* Per-Column Collations: support linguistically-correct sorting per database,
  table or column.
* Unlogged Tables: greatly improves performance for ephemeral data

Our community of contributors innovates with cutting-edge features. Version 9.1
includes several which are new to the database industry, such as:
* K-Nearest-Neighbor Indexing: index on "distance" for faster location \ 
and text
  search queries
* Serializable Snapshot Isolation: keeps concurrent transactions consistent
  without blocking, using "true serializability"
* Writeable Common Table Expressions: execute complex multi-stage data updates
  in a single query
* Security-Enhanced Postgres: deploy military-grade security and Mandatory
  Access Control