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DbEnv::set_tas_spins
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#include <db_cxx.h>
static int
DbEnv::set_tas_spins(u_int32_t tas_spins);
Description
Specify that test-and-set mutexes should spin tas_spins times
without blocking. The value defaults to 1 on uniprocessor systems and
to 50 times the number of processors on multiprocessor systems.
The DbEnv::set_tas_spins interface affects the entire application, not a single
database or database environment.
Although the DbEnv::set_tas_spins interface may be used to configure Berkeley DB at any time
during the life of the application, it should normally be called before
making any calls to the db_env_create or db_create methods.
The DbEnv::set_tas_spins 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.
The database environment's test-and-set spin count 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_tas_spins", one or more whitespace characters,
and the number of spins. Because the DB_CONFIG file is read when the database
environment is opened, it will silently overrule configuration done
before that time.
Errors
The DbEnv::set_tas_spins method may fail and throw an exception or return a non-zero error for the following conditions:
- EINVAL
- An invalid flag value or parameter was specified.
The DbEnv::set_tas_spins method may fail and throw an exception or return a non-zero error for errors specified for other Berkeley DB and C library or system methods.
If a catastrophic error has occurred, the DbEnv::set_tas_spins method may fail and either
return DB_RUNRECOVERY or throw an exception encapsulating
DB_RUNRECOVERY, in which case all subsequent Berkeley DB calls will fail
in the same way.
Class
DbEnv
See Also
DbEnv::close,
DbEnv::err, DbEnv::errx
DbEnv::open,
DbEnv::remove,
DbEnv::set_alloc,
DbEnv::set_cachesize,
DbEnv::set_data_dir,
DbEnv::set_errcall,
DbEnv::set_errfile,
DbEnv::set_error_stream,
DbEnv::set_errpfx,
DbEnv::set_feedback,
DbEnv::set_flags,
DbEnv::set_paniccall,
DbEnv::set_recovery_init,
DbEnv::set_rpc_server,
DbEnv::set_shm_key,
DbEnv::set_tas_spins,
DbEnv::set_tmp_dir,
DbEnv::set_timeout,
DbEnv::set_verbose,
DbEnv::strerror
and
DbEnv::version.
Copyright Sleepycat Software
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