/*****************************************************************************

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Portions of this file contain modifications contributed and copyrighted by
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*****************************************************************************/

/** @file include/srv0conc.h

 InnoDB concurrency manager header file

 Created 2011/04/18 Sunny Bains
 *******************************************************/

#ifndef srv_conc_h
#define srv_conc_h

/** We are prepared for a situation that we have this many threads waiting for
a semaphore inside InnoDB. */

extern uint32_t srv_max_n_threads;

/** The following controls how many threads we let inside InnoDB concurrently:
threads waiting for locks are not counted into the number because otherwise
we could get a deadlock. Value of 0 will disable the concurrency check. */

extern ulong srv_thread_concurrency;

struct row_prebuilt_t;
/** Puts an OS thread to wait if there are too many concurrent threads
 (>= srv_thread_concurrency) inside InnoDB. The threads wait in a FIFO queue.
 @param[in,out] prebuilt        row prebuilt handler
 @return Innodb error code. */
dberr_t srv_conc_enter_innodb(row_prebuilt_t *prebuilt);

/** This lets a thread enter InnoDB regardless of the number of threads inside
 InnoDB. This must be called when a thread ends a lock wait. */
void srv_conc_force_enter_innodb(trx_t *trx); /*!< in: transaction object
                                              associated with the thread */

/** This must be called when a thread exits InnoDB in a lock wait or at the
 end of an SQL statement. */
void srv_conc_force_exit_innodb(trx_t *trx); /*!< in: transaction object
                                             associated with the thread */

/** Get the count of threads waiting inside InnoDB. */
int32_t srv_conc_get_waiting_threads(void);

/** Get the count of threads active inside InnoDB. */
int32_t srv_conc_get_active_threads(void);

#endif /* srv_conc_h */
