Berkeley DB: DbLockTab::detect
Description: Berkeley DB: An embedded database programmatic toolkit.
Keywords: embedded,database,programmatic,toolkit,b+tree,btr ee,hash,hashing,transaction,transactions,locking,logging,access method,access me thods,java,C,C++

# DbLockTab::detect

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    #include <db_cxx.h>

    int
    DbLockTab::detect(u_int32_t flags, u_int32_t atype);

# Description

The DbLockTab::detect method runs one iteration of the deadlock detector. The deadlock detector traverses the lock table, and for each deadlock it finds, marks one of the participating transactions for abort.

The flags value is specified by logically OR'ing together one or more of the following values:

DB_LOCK_CONFLICT
  Only run the deadlock detector if a lock conflict has occurred since the last time that the deadlock detector was run.

The atype parameter specifies which transaction to abort in the case of deadlock. It must be set to one of values described for the lk_detect field of the DbEnv object.

The DbLockTab::detect method is the underlying method used by the db_deadlock utility. See the db_deadlock utility source code for an example of using DbLockTab::detect in a POSIX 1003.1 environment.

The DbLockTab::detect method either returns errno or throws an exception that encapsulates an errno on failure, and 0 on success.

# Errors

If a fatal error occurs in Berkeley DB, the DbLockTab::detect method may fail and either return DB_RUNRECOVERY or throw an exception encapsulating DB_RUNRECOVERY, at which point all subsequent database calls will also fail in the same way. Methods marked as returning errno will, by default, throw an exception that encapsulates the error information. The default error behavior can be changed, see DbException.

The DbLockTab::detect method may fail and throw an exception for any of the errors specified for the following Berkeley DB and C library functions: abort(3), fcntl(3), fflush(3), fprintf(3), free(3), fsync(3), getpid(3), lseek(3), malloc(3), memcpy(3), memset(3), mmap(3), munmap(3), shmat(3), shmdt(3), sprintf(3), strerror(3), vfprintf(3), vsnprintf(3), and write(3).

# Class

DbLockTab

# See Also

DbLockTab::close, DbLockTab::detect, DbLockTab::get, DbLockTab::id, DbLockTab::open, DbLockTab::stat DbLockTab::unlink and DbLockTab::vec.`