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Berkeley DB: DbEnv::set_timeout
DbEnv::set_timeout
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#include <db_cxx.h>
int
DbEnv::set_timeout(db_timeout_t timeout, u_int32_t flags);
int
DbEnv::get_timeout(db_timeout_t *timeoutp, u_int32_t flag);
Description: DbEnv::set_timeout
The DbEnv::set_timeout method sets timeout values for locks or
transactions in the database environment.
Timeouts are checked whenever a thread of control blocks on a lock or
when deadlock detection is performed. (In the case of
DB_SET_LOCK_TIMEOUT, the lock is one requested explicitly
through the Lock subsystem interfaces. In the case of
DB_SET_TXN_TIMEOUT, the lock is one requested on behalf of a
transaction. In either case, it may be a lock requested by the database
access methods underlying the application.) As timeouts are only
checked when the lock request first blocks or when deadlock detection
is performed, the accuracy of the timeout depends on how often deadlock
detection is performed.
Timeout values specified for the database environment may be overridden
on a per-lock or per-transaction basis. See DbEnv::lock_vec and
DbTxn::set_timeout for more information.
The DbEnv::set_timeout method configures a database environment, not only operations
performed using the specified DbEnv handle.
The DbEnv::set_timeout method may be called at any time during the life of the
application.
The DbEnv::set_timeout method
either returns a non-zero error value
or throws an exception that encapsulates a non-zero error value on
failure, and returns 0 on success.
Parameters
- flags
- The flags parameter must be set to one of the following values:
- DB_SET_LOCK_TIMEOUT
- Set the timeout value for locks in this database environment.
The database environment's lock timeout value may also be set using the environment's
DB_CONFIG file. The syntax of the entry in that file is a
single line with the string "set_lock_timeout", one or more whitespace characters,
and the lock timeout value.
Because the DB_CONFIG file is read when the database
environment is opened, it will silently overrule configuration done
before that time.
- DB_SET_TXN_TIMEOUT
- Set the timeout value for transactions in this database environment.
The database environment's transaction timeout value may also be set using the environment's
DB_CONFIG file. The syntax of the entry in that file is a
single line with the string "set_txn_timeout", one or more whitespace characters,
and the transaction timeout value.
Because the DB_CONFIG file is read when the database
environment is opened, it will silently overrule configuration done
before that time.
- timeout
- The timeout parameter is the timeout value. It must be specified
as an unsigned 32-bit number of microseconds, limiting the maximum timeout
to roughly 71 minutes.
Errors
The DbEnv::set_timeout method
may fail and throw
DbException,
encapsulating one of the following non-zero errors, or return one of
the following non-zero errors:
- EINVAL
- An
invalid flag value or parameter was specified.
Description: DbEnv::get_timeout
The DbEnv::get_timeout method returns a timeout value, in microseconds.
The DbEnv::get_timeout method may be called at any time during the life of the
application.
The DbEnv::get_timeout method
either returns a non-zero error value
or throws an exception that encapsulates a non-zero error value on
failure, and returns 0 on success.
Parameters
- flag
- The flags parameter must be set to one of the following values:
- DB_SET_LOCK_TIMEOUT
- Return the timeout value for locks in this database environment.
- DB_SET_TXN_TIMEOUT
- Return the timeout value for transactions in this database environment.
- timeoutp
- The timeoutp parameter references memory into which
the timeout value of the specified flag parameter is copied.
Class
DbEnv
See Also
Database Environments and Related Methods
Copyright (c) 1996-2004 Sleepycat Software, Inc. - All rights reserved.
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