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/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 2006, 2012 Oracle and/or its affiliates. All rights reserved.
*
* $Id$
*/
#include "db_config.h"
#include "db_int.h"
static REPMGR_MESSAGE *available_work __P((ENV *));
/*
* Deallocates memory used by all messages on the queue.
*
* PUBLIC: int __repmgr_queue_destroy __P((ENV *));
*/
int
__repmgr_queue_destroy(env)
ENV *env;
{
DB_REP *db_rep;
REPMGR_MESSAGE *m;
REPMGR_CONNECTION *conn;
int ret, t_ret;
db_rep = env->rep_handle;
ret = 0;
while (!STAILQ_EMPTY(&db_rep->input_queue.header)) {
m = STAILQ_FIRST(&db_rep->input_queue.header);
STAILQ_REMOVE_HEAD(&db_rep->input_queue.header, entries);
if (m->msg_hdr.type == REPMGR_APP_MESSAGE) {
if ((conn = m->v.appmsg.conn) != NULL &&
(t_ret = __repmgr_decr_conn_ref(env, conn)) != 0 &&
ret == 0)
ret = t_ret;
}
__os_free(env, m);
}
return (ret);
}
/*
* PUBLIC: int __repmgr_queue_get __P((ENV *,
* PUBLIC: REPMGR_MESSAGE **, REPMGR_RUNNABLE *));
*
* Get the first input message from the queue and return it to the caller. The
* caller hereby takes responsibility for the entire message buffer, and should
* free it when done.
*
* Caller must hold mutex.
*/
int
__repmgr_queue_get(env, msgp, th)
ENV *env;
REPMGR_MESSAGE **msgp;
REPMGR_RUNNABLE *th;
{
DB_REP *db_rep;
REPMGR_MESSAGE *m;
#ifdef DB_WIN32
HANDLE wait_events[2];
#endif
int ret;
ret = 0;
db_rep = env->rep_handle;
while ((m = available_work(env)) == NULL &&
db_rep->repmgr_status == running && !th->quit_requested) {
#ifdef DB_WIN32
/*
* On Windows, msg_avail means either there's something in the
* queue, or we're all finished. So, reset the event if that is
* not true.
*/
if (STAILQ_EMPTY(&db_rep->input_queue.header) &&
db_rep->repmgr_status == running &&
!ResetEvent(db_rep->msg_avail)) {
ret = GetLastError();
goto err;
}
wait_events[0] = db_rep->msg_avail;
wait_events[1] = th->quit_event;
UNLOCK_MUTEX(db_rep->mutex);
ret = WaitForMultipleObjects(2, wait_events, FALSE, INFINITE);
LOCK_MUTEX(db_rep->mutex);
if (ret == WAIT_FAILED) {
ret = GetLastError();
goto err;
}
#else
if ((ret = pthread_cond_wait(&db_rep->msg_avail,
db_rep->mutex)) != 0)
goto err;
#endif
}
if (db_rep->repmgr_status == stopped || th->quit_requested)
ret = DB_REP_UNAVAIL;
else {
STAILQ_REMOVE(&db_rep->input_queue.header,
m, __repmgr_message, entries);
db_rep->input_queue.size--;
*msgp = m;
}
err:
return (ret);
}
/*
* Gets an "available" item of work (i.e., a message) from the input queue. If
* there are plenty of message threads currently available, then we simply
* return the first thing on the queue, regardless of what type of message it
* is. But otherwise skip over any message type that may possibly turn out to
* be "long-running", so that we avoid starving out the important rep message
* processing.
*/
static REPMGR_MESSAGE *
available_work(env)
ENV *env;
{
DB_REP *db_rep;
REPMGR_MESSAGE *m;
db_rep = env->rep_handle;
if (STAILQ_EMPTY(&db_rep->input_queue.header))
return (NULL);
/*
* The "non_rep_th" field is the dynamically varying count of threads
* currently processing non-replication messages (a.k.a. possibly
* long-running messages, a.k.a. "deferrable"). We always ensure that
* db_rep->nthreads > reserved.
*/
if (db_rep->nthreads > db_rep->non_rep_th + RESERVED_MSG_TH(env))
return (STAILQ_FIRST(&db_rep->input_queue.header));
STAILQ_FOREACH(m, &db_rep->input_queue.header, entries) {
if (!IS_DEFERRABLE(m->msg_hdr.type))
return (m);
}
return (NULL);
}
/*
* PUBLIC: int __repmgr_queue_put __P((ENV *, REPMGR_MESSAGE *));
*
* !!!
* Caller must hold repmgr->mutex.
*/
int
__repmgr_queue_put(env, msg)
ENV *env;
REPMGR_MESSAGE *msg;
{
DB_REP *db_rep;
db_rep = env->rep_handle;
STAILQ_INSERT_TAIL(&db_rep->input_queue.header, msg, entries);
db_rep->input_queue.size++;
return (__repmgr_signal(&db_rep->msg_avail));
}
/*
* PUBLIC: int __repmgr_queue_size __P((ENV *));
*
* !!!
* Caller must hold repmgr->mutex.
*/
int
__repmgr_queue_size(env)
ENV *env;
{
return (env->rep_handle->input_queue.size);
}
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