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<h1>DB_ENV->set_lg_bsize</h1>
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<h3><pre>
#include <db.h>
<p>
int
DB_ENV->set_lg_bsize(DB_ENV *dbenv, u_int32_t lg_bsize);
</pre></h3>
<h1>Description</h1>
<p>Set the size of the in-memory log buffer, in bytes. By default, or if
the value is set to 0, a size of 32K is used. The size of the log file
(see <a href="../api_c/env_set_lg_max.html">DB_ENV->set_lg_max</a>) must be at least four times the size of the
the in-memory log buffer.
<p>Log information is stored in-memory until the storage space fills up
or transaction commit forces the information to be flushed to stable
storage. In the presence of long-running transactions or transactions
producing large amounts of data, larger buffer sizes can increase
throughput.
<p>The DB_ENV->set_lg_bsize method configures a database environment, not only operations
performed using the specified <a href="../api_c/env_class.html">DB_ENV</a> handle.
<p>The DB_ENV->set_lg_bsize interface may not be called after the <a href="../api_c/env_open.html">DB_ENV->open</a>
interface is called.
If the database environment already exists when
<a href="../api_c/env_open.html">DB_ENV->open</a> is called, the information specified to DB_ENV->set_lg_bsize
will be ignored.
<p>The DB_ENV->set_lg_bsize method returns a non-zero error value on failure and 0 on success.
<p>The database environment's log buffer size may also be set using the environment's
<b>DB_CONFIG</b> file. The syntax of the entry in that file is a
single line with the string "set_lg_bsize", one or more whitespace characters,
and the size in bytes. Because the <b>DB_CONFIG</b> file is read when the database
environment is opened, it will silently overrule configuration done
before that time.
<h1>Errors</h1>
<p>The DB_ENV->set_lg_bsize method may fail and return a non-zero error for the following conditions:
<p><dl compact>
<p><dt>EINVAL<dd>An invalid flag value or parameter was specified.
<p>Called after <a href="../api_c/env_open.html">DB_ENV->open</a> was called.
<p>The size of the log file is less than four times the size of the in-memory
log buffer.
</dl>
<p>The DB_ENV->set_lg_bsize method may fail and return a non-zero error for errors specified for other Berkeley DB and C library or system functions.
If a catastrophic error has occurred, the DB_ENV->set_lg_bsize method may fail and
return <a href="../ref/program/errorret.html#DB_RUNRECOVERY">DB_RUNRECOVERY</a>,
in which case all subsequent Berkeley DB calls will fail in the same way.
<h1>Class</h1>
<a href="../api_c/env_class.html">DB_ENV</a>, <a href="../api_c/logc_class.html">DB_LOGC</a>, <a href="../api_c/lsn_class.html">DB_LSN</a>
<h1>See Also</h1>
<a href="../api_c/log_list.html">Logging Subsystem and Related Methods</a>
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