The release notes contain the significant changes in each PostgreSQL release, with major features and migration issues listed at the top. The release notes do not contain changes that affect only a few users or changes that are internal and therefore not user-visible. For example, the optimizer is improved in almost every release, but the improvements are usually observed by users as simply faster queries.
A complete list of changes for each release can be obtained by viewing the Git logs for each release. The pgsql-committers email list records all source code changes as well. There is also a web interface that shows changes to specific files.
The name appearing next to each item represents the major developer for that item. Of course all changes involve community discussion and patch review, so each item is truly a community effort.
Release date: 2010-12-16
This release contains a variety of fixes from 8.1.22. For information about new features in the 8.1 major release, see Section E.24.
This is expected to be the last PostgreSQL release in the 8.1.X series. Users are encouraged to update to a newer release branch soon.
A dump/restore is not required for those running 8.1.X. However, if you are upgrading from a version earlier than 8.1.18, see the release notes for 8.1.18.
Force the default wal_sync_method to be fdatasync on Linux (Tom Lane, Marti Raudsepp)
The default on Linux has actually been fdatasync for many years, but recent kernel changes caused PostgreSQL to choose open_datasync instead. This choice did not result in any performance improvement, and caused outright failures on certain filesystems, notably ext4 with the data=journal mount option.
Fix recovery from base backup when the starting checkpoint WAL record is not in the same WAL segment as its redo point (Jeff Davis)
Add support for detecting register-stack overrun on IA64 (Tom Lane)
The IA64 architecture has two hardware stacks. Full prevention of stack-overrun failures requires checking both.
Add a check for stack overflow in
copyObject() (Tom Lane)
Certain code paths could crash due to stack overflow given a sufficiently complex query.
Fix detection of page splits in temporary GiST indexes (Heikki Linnakangas)
It is possible to have a "concurrent" page split in a temporary index, if for example there is an open cursor scanning the index when an insertion is done. GiST failed to detect this case and hence could deliver wrong results when execution of the cursor continued.
Avoid memory leakage while ANALYZE'ing complex index expressions (Tom Lane)
Ensure an index that uses a whole-row Var still depends on its table (Tom Lane)
An index declared like create index i on t (foo(t.*)) would not automatically get dropped when its table was dropped.
Do not "inline" a SQL function with multiple OUT parameters (Tom Lane)
This avoids a possible crash due to loss of information about the expected result rowtype.
Fix constant-folding of COALESCE() expressions (Tom Lane)
The planner would sometimes attempt to evaluate sub-expressions that in fact could never be reached, possibly leading to unexpected errors.
Add print functionality for InhRelation nodes (Tom Lane)
This avoids a failure when debug_print_parse is enabled and certain types of query are executed.
Fix incorrect calculation of distance from a point to a horizontal line segment (Tom Lane)
This bug affected several different geometric distance-measurement operators.
Fix PL/pgSQL's handling of "simple" expressions to not fail in recursion or error-recovery cases (Tom Lane)
Fix bug in contrib/cube's GiST picksplit algorithm (Alexander Korotkov)
This could result in considerable inefficiency, though not actually incorrect answers, in a GiST index on a cube column. If you have such an index, consider REINDEXing it after installing this update.
Don't emit "identifier will be truncated" notices in contrib/dblink except when creating new connections (Itagaki Takahiro)
Fix potential coredump on missing public key in contrib/pgcrypto (Marti Raudsepp)
Fix memory leak in contrib/xml2's XPath query functions (Tom Lane)
Update time zone data files to tzdata release 2010o for DST law changes in Fiji and Samoa; also historical corrections for Hong Kong.