/*
* __session_close --
* WT_SESSION->close method.
*/
static int
__session_close(WT_SESSION *wt_session, const char *config)
{
WT_CONNECTION_IMPL *conn;
WT_CURSOR *cursor;
WT_DECL_RET;
WT_SESSION_IMPL *session;
int tret;
conn = (WT_CONNECTION_IMPL *)wt_session->connection;
session = (WT_SESSION_IMPL *)wt_session;
SESSION_API_CALL(session, close, config, cfg);
WT_UNUSED(cfg);
/* Rollback any active transaction. */
if (F_ISSET(&session->txn, TXN_RUNNING))
WT_TRET(__session_rollback_transaction(wt_session, NULL));
/* Close all open cursors. */
while ((cursor = TAILQ_FIRST(&session->cursors)) != NULL)
WT_TRET(cursor->close(cursor));
WT_ASSERT(session, session->ncursors == 0);
/*
* Acquire the schema lock: we may be closing btree handles.
*
* Note that in some special cases, the schema may already be locked
* (e.g., if this session is an LSM tree worker and the tree is being
* dropped).
*/
WT_WITH_SCHEMA_LOCK_OPT(session, tret = __session_close_cache(session));
WT_TRET(tret);
/* Discard metadata tracking. */
__wt_meta_track_discard(session);
/* Discard scratch buffers. */
__wt_scr_discard(session);
/* Free transaction information. */
__wt_txn_destroy(session);
/* Confirm we're not holding any hazard references. */
__wt_hazard_close(session);
/* Free the reconciliation information. */
__wt_rec_destroy(session, &session->reconcile);
/* Free the eviction exclusive-lock information. */
__wt_free(session, session->excl);
/* Destroy the thread's mutex. */
if (session->cond != NULL)
(void)__wt_cond_destroy(session, session->cond);
/* The API lock protects opening and closing of sessions. */
__wt_spin_lock(session, &conn->api_lock);
/*
* Sessions are re-used, clear the structure: this code sets the active
* field to 0, which will exclude the hazard array from review by the
* eviction thread. Note: there's no serialization support around the
* review of the hazard array, which means threads checking for hazard
* references first check the active field (which may be 0) and then use
* the hazard pointer (which cannot be NULL). For this reason, clear
* the session structure carefully.
*
* We don't need to publish here, because regardless of the active field
* being non-zero, the hazard reference is always valid.
*/
WT_SESSION_CLEAR(session);
session = conn->default_session;
/*
* Decrement the count of active sessions if that's possible: a session
* being closed may or may not be at the end of the array, step toward
* the beginning of the array until we reach an active session.
*/
while (conn->sessions[conn->session_cnt - 1].active == 0)
if (--conn->session_cnt == 0)
break;
__wt_spin_unlock(session, &conn->api_lock);
err: API_END_NOTFOUND_MAP(session, ret);
}
/*
* __session_close --
* WT_SESSION->close method.
*/
static int
__session_close(WT_SESSION *wt_session, const char *config)
{
WT_BTREE_SESSION *btree_session;
WT_CONNECTION_IMPL *conn;
WT_CURSOR *cursor;
WT_SESSION_IMPL *session, **tp;
int ret;
conn = (WT_CONNECTION_IMPL *)wt_session->connection;
session = (WT_SESSION_IMPL *)wt_session;
SESSION_API_CALL(session, close, config, cfg);
WT_UNUSED(cfg);
while ((cursor = TAILQ_FIRST(&session->cursors)) != NULL)
WT_TRET(cursor->close(cursor));
while ((btree_session = TAILQ_FIRST(&session->btrees)) != NULL)
WT_TRET(__wt_session_remove_btree(session, btree_session, 0));
WT_TRET(__wt_schema_close_tables(session));
__wt_spin_lock(session, &conn->spinlock);
/* Discard scratch buffers. */
__wt_scr_discard(session);
/* Confirm we're not holding any hazard references. */
__wt_hazard_empty(session);
/* Free the reconciliation information. */
__wt_rec_destroy(session);
/* Free the eviction exclusive-lock information. */
__wt_free(session, session->excl);
/* Destroy the thread's mutex. */
if (session->cond != NULL)
(void)__wt_cond_destroy(session, session->cond);
/*
* Replace the session reference we're closing with the last entry in
* the table, then clear the last entry. As far as the walk of the
* server threads is concerned, it's OK if the session appears twice,
* or if it doesn't appear at all, so these lines can race all they
* want.
*/
for (tp = conn->sessions; *tp != session; ++tp)
;
--conn->session_cnt;
*tp = conn->sessions[conn->session_cnt];
conn->sessions[conn->session_cnt] = NULL;
/*
* Publish, making the session array entry available for re-use. There
* must be a barrier here to ensure the cleanup above completes before
* the entry is re-used.
*/
WT_PUBLISH(session->iface.connection, NULL);
session = &conn->default_session;
__wt_spin_unlock(session, &conn->spinlock);
err:
API_END_NOTFOUND_MAP(session, ret);
}