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/*-
* Copyright (c) 2014-2015 MongoDB, Inc.
* Copyright (c) 2008-2014 WiredTiger, Inc.
* All rights reserved.
*
* See the file LICENSE for redistribution information.
*/
#include "wt_internal.h"
static int __ckpt_server_start(WT_CONNECTION_IMPL *);
/*
* __ckpt_server_config --
* Parse and setup the checkpoint server options.
*/
static int
__ckpt_server_config(WT_SESSION_IMPL *session, const char **cfg, bool *startp)
{
WT_CONFIG_ITEM cval;
WT_CONNECTION_IMPL *conn;
WT_DECL_ITEM(tmp);
WT_DECL_RET;
char *p;
conn = S2C(session);
/*
* The checkpoint configuration requires a wait time and/or a log
* size -- if one is not set, we're not running at all.
* Checkpoints based on log size also require logging be enabled.
*/
WT_RET(__wt_config_gets(session, cfg, "checkpoint.wait", &cval));
conn->ckpt_usecs = (uint64_t)cval.val * 1000000;
WT_RET(__wt_config_gets(session, cfg, "checkpoint.log_size", &cval));
conn->ckpt_logsize = (wt_off_t)cval.val;
__wt_log_written_reset(session);
if ((conn->ckpt_usecs == 0 && conn->ckpt_logsize == 0) ||
(conn->ckpt_logsize && conn->ckpt_usecs == 0 &&
!FLD_ISSET(conn->log_flags, WT_CONN_LOG_ENABLED))) {
*startp = false;
return (0);
}
*startp = true;
/*
* The application can specify a checkpoint name, which we ignore if
* it's our default.
*/
WT_RET(__wt_config_gets(session, cfg, "checkpoint.name", &cval));
if (cval.len != 0 &&
!WT_STRING_MATCH(WT_CHECKPOINT, cval.str, cval.len)) {
WT_RET(__wt_checkpoint_name_ok(session, cval.str, cval.len));
WT_RET(__wt_scr_alloc(session, cval.len + 20, &tmp));
WT_ERR(__wt_buf_fmt(
session, tmp, "name=%.*s", (int)cval.len, cval.str));
WT_ERR(__wt_strdup(session, tmp->data, &p));
__wt_free(session, conn->ckpt_config);
conn->ckpt_config = p;
}
err: __wt_scr_free(session, &tmp);
return (ret);
}
/*
* __ckpt_server --
* The checkpoint server thread.
*/
static WT_THREAD_RET
__ckpt_server(void *arg)
{
WT_CONNECTION_IMPL *conn;
WT_DECL_RET;
WT_SESSION *wt_session;
WT_SESSION_IMPL *session;
session = arg;
conn = S2C(session);
wt_session = (WT_SESSION *)session;
while (F_ISSET(conn, WT_CONN_SERVER_RUN) &&
F_ISSET(conn, WT_CONN_SERVER_CHECKPOINT)) {
/*
* Wait...
* NOTE: If the user only configured logsize, then usecs
* will be 0 and this wait won't return until signalled.
*/
WT_ERR(
__wt_cond_wait(session, conn->ckpt_cond, conn->ckpt_usecs));
/* Checkpoint the database. */
WT_ERR(wt_session->checkpoint(wt_session, conn->ckpt_config));
/* Reset. */
if (conn->ckpt_logsize) {
__wt_log_written_reset(session);
conn->ckpt_signalled = 0;
/*
* In case we crossed the log limit during the
* checkpoint and the condition variable was already
* signalled, do a tiny wait to clear it so we don't do
* another checkpoint immediately.
*/
WT_ERR(__wt_cond_wait(session, conn->ckpt_cond, 1));
}
}
if (0) {
err: WT_PANIC_MSG(session, ret, "checkpoint server error");
}
return (WT_THREAD_RET_VALUE);
}
/*
* __ckpt_server_start --
* Start the checkpoint server thread.
*/
static int
__ckpt_server_start(WT_CONNECTION_IMPL *conn)
{
WT_SESSION_IMPL *session;
/* Nothing to do if the server is already running. */
if (conn->ckpt_session != NULL)
return (0);
F_SET(conn, WT_CONN_SERVER_CHECKPOINT);
/* The checkpoint server gets its own session. */
WT_RET(__wt_open_internal_session(
conn, "checkpoint-server", true, true, &conn->ckpt_session));
session = conn->ckpt_session;
/*
* Checkpoint does enough I/O it may be called upon to perform slow
* operations for the block manager.
*/
F_SET(session, WT_SESSION_CAN_WAIT);
WT_RET(__wt_cond_alloc(
session, "checkpoint server", false, &conn->ckpt_cond));
/*
* Start the thread.
*/
WT_RET(__wt_thread_create(
session, &conn->ckpt_tid, __ckpt_server, session));
conn->ckpt_tid_set = 1;
return (0);
}
/*
* __wt_checkpoint_server_create --
* Configure and start the checkpoint server.
*/
int
__wt_checkpoint_server_create(WT_SESSION_IMPL *session, const char *cfg[])
{
WT_CONNECTION_IMPL *conn;
bool start;
conn = S2C(session);
start = false;
/* If there is already a server running, shut it down. */
if (conn->ckpt_session != NULL)
WT_RET(__wt_checkpoint_server_destroy(session));
WT_RET(__ckpt_server_config(session, cfg, &start));
if (start)
WT_RET(__ckpt_server_start(conn));
return (0);
}
/*
* __wt_checkpoint_server_destroy --
* Destroy the checkpoint server thread.
*/
int
__wt_checkpoint_server_destroy(WT_SESSION_IMPL *session)
{
WT_CONNECTION_IMPL *conn;
WT_DECL_RET;
WT_SESSION *wt_session;
conn = S2C(session);
F_CLR(conn, WT_CONN_SERVER_CHECKPOINT);
if (conn->ckpt_tid_set) {
WT_TRET(__wt_cond_signal(session, conn->ckpt_cond));
WT_TRET(__wt_thread_join(session, conn->ckpt_tid));
conn->ckpt_tid_set = 0;
}
WT_TRET(__wt_cond_destroy(session, &conn->ckpt_cond));
__wt_free(session, conn->ckpt_config);
/* Close the server thread's session. */
if (conn->ckpt_session != NULL) {
wt_session = &conn->ckpt_session->iface;
WT_TRET(wt_session->close(wt_session, NULL));
}
/*
* Ensure checkpoint settings are cleared - so that reconfigure doesn't
* get confused.
*/
conn->ckpt_session = NULL;
conn->ckpt_tid_set = 0;
conn->ckpt_cond = NULL;
conn->ckpt_config = NULL;
conn->ckpt_usecs = 0;
return (ret);
}
/*
* __wt_checkpoint_signal --
* Signal the checkpoint thread if sufficient log has been written.
* Return 1 if this signals the checkpoint thread, 0 otherwise.
*/
int
__wt_checkpoint_signal(WT_SESSION_IMPL *session, wt_off_t logsize)
{
WT_CONNECTION_IMPL *conn;
conn = S2C(session);
WT_ASSERT(session, WT_CKPT_LOGSIZE(conn));
if (logsize >= conn->ckpt_logsize && !conn->ckpt_signalled) {
WT_RET(__wt_cond_signal(session, conn->ckpt_cond));
conn->ckpt_signalled = 1;
}
return (0);
}
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