/*
* __log_server --
* The log server thread.
*/
static WT_THREAD_RET
__log_server(void *arg)
{
WT_CONNECTION_IMPL *conn;
WT_DECL_RET;
WT_LOG *log;
WT_SESSION_IMPL *session;
u_int locked;
session = arg;
conn = S2C(session);
log = conn->log;
locked = 0;
while (F_ISSET(conn, WT_CONN_LOG_SERVER_RUN)) {
/*
* Perform log pre-allocation.
*/
if (conn->log_prealloc > 0)
WT_ERR(__log_prealloc_once(session));
/*
* Perform the archive.
*/
if (FLD_ISSET(conn->log_flags, WT_CONN_LOG_ARCHIVE)) {
if (__wt_try_writelock(
session, log->log_archive_lock) == 0) {
locked = 1;
WT_ERR(__log_archive_once(session, 0));
WT_ERR( __wt_writeunlock(
session, log->log_archive_lock));
locked = 0;
} else
WT_ERR(__wt_verbose(session, WT_VERB_LOG,
"log_archive: Blocked due to open log "
"cursor holding archive lock"));
}
/* Wait until the next event. */
WT_ERR(__wt_cond_wait(session, conn->log_cond, WT_MILLION));
}
if (0) {
err: __wt_err(session, ret, "log server error");
}
if (locked)
(void)__wt_writeunlock(session, log->log_archive_lock);
return (WT_THREAD_RET_VALUE);
}
/*
* __log_server --
* The log server thread.
*/
static WT_THREAD_RET
__log_server(void *arg)
{
WT_CONNECTION_IMPL *conn;
WT_DECL_RET;
WT_LOG *log;
WT_SESSION_IMPL *session;
int freq_per_sec, signalled;
session = arg;
conn = S2C(session);
log = conn->log;
signalled = 0;
/*
* Set this to the number of times per second we want to force out the
* log slot buffer.
*/
#define WT_FORCE_PER_SECOND 20
freq_per_sec = WT_FORCE_PER_SECOND;
/*
* The log server thread does a variety of work. It forces out any
* buffered log writes. It pre-allocates log files and it performs
* log archiving. The reason the wrlsn thread does not force out
* the buffered writes is because we want to process and move the
* write_lsn forward as quickly as possible. The same reason applies
* to why the log file server thread does not force out the writes.
* That thread does fsync calls which can take a long time and we
* don't want log records sitting in the buffer over the time it
* takes to sync out an earlier file.
*/
while (F_ISSET(conn, WT_CONN_LOG_SERVER_RUN)) {
/*
* Slots depend on future activity. Force out buffered
* writes in case we are idle. This cannot be part of the
* wrlsn thread because of interaction advancing the write_lsn
* and a buffer may need to wait for the write_lsn to advance
* in the case of a synchronous buffer. We end up with a hang.
*/
WT_ERR_BUSY_OK(__wt_log_force_write(session, 0));
/*
* We don't want to archive or pre-allocate files as often as
* we want to force out log buffers. Only do it once per second
* or if the condition was signalled.
*/
if (--freq_per_sec <= 0 || signalled != 0) {
freq_per_sec = WT_FORCE_PER_SECOND;
/*
* Perform log pre-allocation.
*/
if (conn->log_prealloc > 0)
WT_ERR(__log_prealloc_once(session));
/*
* Perform the archive.
*/
if (FLD_ISSET(conn->log_flags, WT_CONN_LOG_ARCHIVE)) {
if (__wt_try_writelock(
session, log->log_archive_lock) == 0) {
ret = __log_archive_once(session, 0);
WT_TRET(__wt_writeunlock(
session, log->log_archive_lock));
WT_ERR(ret);
} else
WT_ERR(
__wt_verbose(session, WT_VERB_LOG,
"log_archive: Blocked due to open "
"log cursor holding archive lock"));
}
}
/* Wait until the next event. */
WT_ERR(__wt_cond_wait_signal(session, conn->log_cond,
WT_MILLION / WT_FORCE_PER_SECOND, &signalled));
}
if (0) {
err: __wt_err(session, ret, "log server error");
}
return (WT_THREAD_RET_VALUE);
}
/*
* __log_server --
* The log server thread.
*/
static WT_THREAD_RET
__log_server(void *arg)
{
struct timespec start, now;
WT_CONNECTION_IMPL *conn;
WT_DECL_RET;
WT_LOG *log;
WT_SESSION_IMPL *session;
uint64_t timediff;
bool did_work, locked, signalled;
session = arg;
conn = S2C(session);
log = conn->log;
locked = signalled = false;
/*
* Set this to the number of milliseconds we want to run archive and
* pre-allocation. Start it so that we run on the first time through.
*/
timediff = WT_THOUSAND;
/*
* The log server thread does a variety of work. It forces out any
* buffered log writes. It pre-allocates log files and it performs
* log archiving. The reason the wrlsn thread does not force out
* the buffered writes is because we want to process and move the
* write_lsn forward as quickly as possible. The same reason applies
* to why the log file server thread does not force out the writes.
* That thread does fsync calls which can take a long time and we
* don't want log records sitting in the buffer over the time it
* takes to sync out an earlier file.
*/
did_work = true;
while (F_ISSET(conn, WT_CONN_LOG_SERVER_RUN)) {
/*
* Slots depend on future activity. Force out buffered
* writes in case we are idle. This cannot be part of the
* wrlsn thread because of interaction advancing the write_lsn
* and a buffer may need to wait for the write_lsn to advance
* in the case of a synchronous buffer. We end up with a hang.
*/
WT_ERR_BUSY_OK(__wt_log_force_write(session, 0, &did_work));
/*
* We don't want to archive or pre-allocate files as often as
* we want to force out log buffers. Only do it once per second
* or if the condition was signalled.
*/
if (timediff >= WT_THOUSAND || signalled) {
/*
* Perform log pre-allocation.
*/
if (conn->log_prealloc > 0) {
/*
* Log file pre-allocation is disabled when a
* hot backup cursor is open because we have
* agreed not to rename or remove any files in
* the database directory.
*/
WT_ERR(__wt_readlock(
session, conn->hot_backup_lock));
locked = true;
if (!conn->hot_backup)
WT_ERR(__log_prealloc_once(session));
WT_ERR(__wt_readunlock(
session, conn->hot_backup_lock));
locked = false;
}
/*
* Perform the archive.
*/
if (FLD_ISSET(conn->log_flags, WT_CONN_LOG_ARCHIVE)) {
if (__wt_try_writelock(
session, log->log_archive_lock) == 0) {
ret = __log_archive_once(session, 0);
WT_TRET(__wt_writeunlock(
session, log->log_archive_lock));
WT_ERR(ret);
} else
WT_ERR(
__wt_verbose(session, WT_VERB_LOG,
"log_archive: Blocked due to open "
"log cursor holding archive lock"));
}
}
/* Wait until the next event. */
WT_ERR(__wt_epoch(session, &start));
WT_ERR(__wt_cond_auto_wait_signal(session, conn->log_cond,
did_work, &signalled));
WT_ERR(__wt_epoch(session, &now));
timediff = WT_TIMEDIFF_MS(now, start);
}
if (0) {
err: __wt_err(session, ret, "log server error");
if (locked)
WT_TRET(__wt_readunlock(
session, conn->hot_backup_lock));
}
return (WT_THREAD_RET_VALUE);
}
