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(mysql.info)BDB start

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BDB startup options
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If you are running with `AUTOCOMMIT=0' then your changes in `BDB'
tables will not be updated until you execute `COMMIT'.  Instead of
commit you can execute `ROLLBACK' to forget your changes. Note:
COMMIT.

If you are running with `AUTOCOMMIT=1' (the default), your changes will
be committed immediately.  You can start an extended transaction with
the `BEGIN WORK' SQL command, after which your changes will not be
committed until you execute `COMMIT' (or decide to `ROLLBACK' the
changes).

The following options to `mysqld' can be used to change the behavior of
BDB tables:

*Option*               *Meaning*
`--bdb-home=directory' Base directory for BDB tables. This should be the
                       same directory you use for -datadir.
`--bdb-lock-detect=#'  Berkeley lock detect. One of (DEFAULT, OLDEST,
                       RANDOM, or YOUNGEST).
`--bdb-logdir=directory'Berkeley DB log file directory.
`--bdb-no-sync'        Don't synchronously flush logs.
`--bdb-no-recover'     Don't start Berkeley DB in recover mode.
`--bdb-shared-data'    Start Berkeley DB in multi-process mode (Don't
                       use `DB_PRIVATE' when initializing Berkeley DB)
`--bdb-tmpdir=directory'Berkeley DB tempfile name.
`--skip-bdb'           Don't use berkeley db.
`-O                    Set the maximum number of locks possible. Note:
bdb_max_lock=1000'     SHOW VARIABLES.

If you use `--skip-bdb', MySQL will not initialize the Berkeley DB
library and this will save a lot of memory. Of course, you cannot use
`BDB' tables if you are using this option.

Normally you should start `mysqld' without `--bdb-no-recover' if you
intend to use BDB tables.  This may, however, give you problems when you
try to start `mysqld' if the BDB log files are corrupted. Note:
Starting server.

With `bdb_max_lock' you can specify the maximum number of locks (10000
by default) you can have active on a BDB table. You should increase
this if you get errors of type `bdb: Lock table is out of available
locks' or `Got error 12 from ...'  when you have do long transactions
or when `mysqld' has to examine a lot of rows to calculate the query.

You may also want to change `binlog_cache_size' and
`max_binlog_cache_size' if you are using big multi-line transactions.
Note: COMMIT.