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<title>The Berkeley DB Package: DB 2.4.14 Change Log</title>
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<h3 align=center>Berkeley DB 2.4.14 Change Log</h3>

<h3>Interface Changes Introduced in DB 2.4.14:</h3>
<ol>

<p><li>
Enhance the
db_load(1)
utility so that the default behavior is to add data to existing databases
(rather than to always create the database), and to correctly perform
locking for databases running in Berkeley DB environments.  This allows
the use of
db_load(1)
to add key/data pairs to existing, active databases.
<p>
Add a <b>-n</b> option to the
db_load(1)
This option causes
db_load(1)
to refuse to overwrite already existing key/data pairs in databases.

<p><li>
Enhance the
db_stat(1)
utility to display additional information about the shared memory buffer
pool and lock regions.  The new options are <b>-C[Acflmo]</b> for the
lock region, and <b>-M[Ahlm]</b> for the shared memory buffer pool region.
This information is normally intended only for Berkeley DB performance
tuning.

<p>
Add a <b>-N</b> option to the
db_stat(1)
This option keeps
db_stat(1)
from acquiring region locks when reading shared regions, which allows
db_stat(1)
to be used to display information about regions where applications have
crashed while holding region locks.

<p>
Add region reference counts and sizes to all
db_stat(1)
region displays.

<p><li>
Add a new flag, <b>DB_MUTEXLOCKS</b> to the
db_value_set(1)
interface.  This flag causes requests for mutual exclusion mutexes to
be immediately granted without test.  This flag is only intended for
debugging purposes.

</ol>
<h3>B+tree Access Method Bug Fixes:</h3>
<ol>

<p><li>
Fix bug in the B+tree access method where additional cursors could be
incorrectly updated when key/data pairs were added or deleted.

<p><li>
Fix bug where an aborted transaction during a B+tree split could cause
pages to be left pinned.

<p><li>
Fix possible core dump when freeing the (cursor referenced) last item
in the last page in a duplicate chain.

<p><li>
Fix possible core dump when deleting overflow items from duplicate pages.

<p><li>
Fix bug where duplicate page splits could result in database corruption
(common to both B+tree and Hash Access Methods).

</ol>
<h3>Hash Access Method Bug Fixes:</h3>
<ol>

<p><li>
Fix bug where Hash access method recovery did not always correctly recover
key/data pair addition or deletion.

<p><li>
Fix bug where deleting a key in a Hash access method database could cause
a cursor sequentially walking the database to skip records.

<p><li>
Fix bug where duplicate page splits could result in database corruption
(common to both B+tree and Hash Access Methods).

</ol>
<h3>Shared Memory Buffer Pool Bug Fixes:</h3>
<ol>

<p><li>
Fix bug where a DB thread handle could be left locked if a read-only file
descriptor could not be upgraded to read-write during a buffer pool sync
to disk.

</ol>
<h3>Common Shared Region Support Bug Fixes:</h3>
<ol>

<p><li>
Fix bug where private shared memory pool regions could not be created on
architectures without spinlock mutex support.

<p><li>
Fix possible file descriptor leak on HP/UX architecture (reports #150,
#158).

<p><li>
Fix a variety of inconsistencies where, after a failed attempt to open
shared regions, the code recovery paths were incorrect.

</ol>
<h3>Additional Bug Fixes:</h3>
<ol>

<p><li>
Fix possible core dump in
lock_open(1)
when it was called without first creating a Berkeley DB database environment.

</ol>
<h3>Test Suite, Example Program and Build Procedure Bug Fixes and Changes:</h3>
<ol>

<p><li>
Fix build procedures for a number of architectures: affected systems
include VC++ 5.0 and various releases of SunOS, AIX, OSF/1, FreeBSD
and Linux (reports #145, #156).

<p><li>
Fix the Berkeley DB test suite to correctly identify Windows systems
in all cases (the previous method failed for some releases of the
Tcl scripting language).

<p><li>
Fix the <b>ex_thread</b> example program to correctly set the buffer
cache size.

<p><li>
Fix the Berkeley DB test suite to ignore errors where System V shared
memory interfaces (shmget(2)) have not been configured correctly.

<p><li>
Add support for the BSD/OS 4.0 release.

<p><li>
Add support for the SCO OpenServer Release 5 (3.2.2).  (The test suite
has not yet run successfully on this architecture, although we currently
believe that the problems are in the test suite, and not in the Berkeley
DB library itself.)

<p><li>
Change configuration to ignore the FreeBSD shmget(2) interfaces when
ftok(3) is not available from the C library.

<p><li>
Change configuration to fail on the Nextstep architecture.  (Previously,
Berkeley DB would configure successfully, but then not build on Nextstep.)

</ol>
<h3>Additional Changes:</h3>
<ol>

<p><li>
Return EINVAL if the DB_RECOVER or DB_RECOVER_FATAL flags were specified to
db_appinit(3) without also specifying the DB_INIT_TXN flag.

<p><li>
Removed "Additional Change" #7 from the Berkeley DB 2.4.10 release:
<p>
<blockquote>
The mutex locking code has been enhanced to no longer attempt full
test-and-set instructions unless there is a strong probability of
acquiring the mutex. This makes spinning on the mutex significantly
less expensive.
</blockquote>
<p>
Full test-and-set instructions are necessary on some architectures, and
it this change actually decreased performance in some cases.

</ol>

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