Berkeley DB: DbEnv.set_tas_spins
Description: Berkeley DB: An embedded database programmatic toolkit.
Keywords: embedded,database,programmatic,toolkit,b+tree,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,java,C,C++

# DbEnv.set_tas_spins |

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    import com.sleepycat.db.*;

    static int
    DbEnv.set_tas_spins(u_int32_t tas_spins);
    	throws DbException;

# 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 throws an exception that encapsulates a non-zero error value on failure.

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 encapsulating 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 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 throw a DbRunRecoveryException, in which case all subsequent Berkeley DB calls will fail in the same way.

# Class

DbEnv

# See Also

DbEnv.close, DbEnv.get_version_string, DbEnv.open, DbEnv.remove, DbEnv.set_cachesize, DbEnv.set_data_dir, DbEnv.set_errcall, DbEnv.set_error_stream, DbEnv.set_errpfx, DbEnv.set_feedback, DbEnv.set_flags, DbEnv.set_mutexlocks, DbEnv.set_pageyield, DbEnv.set_panicstate, DbEnv.set_recovery_init, DbEnv.set_rpc_server, DbEnv.set_region_init, DbEnv.set_shm_key, DbEnv.set_tas_spins, DbEnv.set_tmp_dir, DbEnv.set_verbose, and DbEnv.strerror.`

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