/*
* __log_file_server --
* The log file server thread. This worker thread manages
* log file operations such as closing and syncing.
*/
static WT_THREAD_RET
__log_file_server(void *arg)
{
WT_CONNECTION_IMPL *conn;
WT_DECL_RET;
WT_FH *close_fh;
WT_LOG *log;
WT_LSN close_end_lsn, min_lsn;
WT_SESSION_IMPL *session;
uint32_t filenum;
bool locked;
session = arg;
conn = S2C(session);
log = conn->log;
locked = false;
while (F_ISSET(conn, WT_CONN_LOG_SERVER_RUN)) {
/*
* If there is a log file to close, make sure any outstanding
* write operations have completed, then fsync and close it.
*/
if ((close_fh = log->log_close_fh) != NULL) {
WT_ERR(__wt_log_extract_lognum(session, close_fh->name,
&filenum));
/*
* We update the close file handle before updating the
* close LSN when changing files. It is possible we
* could see mismatched settings. If we do, yield
* until it is set. This should rarely happen.
*/
while (log->log_close_lsn.l.file < filenum)
__wt_yield();
if (__wt_log_cmp(
&log->write_lsn, &log->log_close_lsn) >= 0) {
/*
* We've copied the file handle, clear out the
* one in the log structure to allow it to be
* set again. Copy the LSN before clearing
* the file handle.
* Use a barrier to make sure the compiler does
* not reorder the following two statements.
*/
close_end_lsn = log->log_close_lsn;
WT_FULL_BARRIER();
log->log_close_fh = NULL;
/*
* Set the close_end_lsn to the LSN immediately
* after ours. That is, the beginning of the
* next log file. We need to know the LSN
* file number of our own close in case earlier
* calls are still in progress and the next one
* to move the sync_lsn into the next file for
* later syncs.
*/
WT_ERR(__wt_fsync(session, close_fh, true));
/*
* We want to have the file size reflect actual
* data with minimal pre-allocated zeroed space.
* We can't truncate the file during hot backup,
* or the underlying file system may not support
* truncate: both are OK, it's just more work
* during cursor traversal.
*/
if (!conn->hot_backup) {
__wt_readlock(
session, conn->hot_backup_lock);
if (!conn->hot_backup)
WT_ERR_ERROR_OK(
__wt_ftruncate(session,
close_fh,
close_end_lsn.l.offset),
ENOTSUP);
__wt_readunlock(
session, conn->hot_backup_lock);
}
WT_SET_LSN(&close_end_lsn,
close_end_lsn.l.file + 1, 0);
__wt_spin_lock(session, &log->log_sync_lock);
locked = true;
WT_ERR(__wt_close(session, &close_fh));
WT_ASSERT(session, __wt_log_cmp(
&close_end_lsn, &log->sync_lsn) >= 0);
log->sync_lsn = close_end_lsn;
__wt_cond_signal(session, log->log_sync_cond);
locked = false;
__wt_spin_unlock(session, &log->log_sync_lock);
}
}
/*
* If a later thread asked for a background sync, do it now.
*/
if (__wt_log_cmp(&log->bg_sync_lsn, &log->sync_lsn) > 0) {
/*
* Save the latest write LSN which is the minimum
* we will have written to disk.
*/
min_lsn = log->write_lsn;
/*
* We have to wait until the LSN we asked for is
* written. If it isn't signal the wrlsn thread
* to get it written.
*
* We also have to wait for the written LSN and the
* sync LSN to be in the same file so that we know we
* have synchronized all earlier log files.
*/
if (__wt_log_cmp(&log->bg_sync_lsn, &min_lsn) <= 0) {
/*
* If the sync file is behind either the one
* wanted for a background sync or the write LSN
* has moved to another file continue to let
* this worker thread process that older file
* immediately.
*/
if ((log->sync_lsn.l.file <
log->bg_sync_lsn.l.file) ||
(log->sync_lsn.l.file < min_lsn.l.file))
continue;
WT_ERR(__wt_fsync(session, log->log_fh, true));
__wt_spin_lock(session, &log->log_sync_lock);
locked = true;
/*
* The sync LSN could have advanced while we
* were writing to disk.
*/
if (__wt_log_cmp(
&log->sync_lsn, &min_lsn) <= 0) {
WT_ASSERT(session,
min_lsn.l.file ==
log->sync_lsn.l.file);
log->sync_lsn = min_lsn;
__wt_cond_signal(
session, log->log_sync_cond);
}
locked = false;
__wt_spin_unlock(session, &log->log_sync_lock);
} else {
__wt_cond_auto_signal(
session, conn->log_wrlsn_cond);
/*
* We do not want to wait potentially a second
* to process this. Yield to give the wrlsn
* thread a chance to run and try again in
* this case.
*/
__wt_yield();
continue;
}
}
/* Wait until the next event. */
__wt_cond_wait(session, conn->log_file_cond, WT_MILLION / 10);
}
if (0) {
err: __wt_err(session, ret, "log close server error");
}
if (locked)
__wt_spin_unlock(session, &log->log_sync_lock);
return (WT_THREAD_RET_VALUE);
}
/*
* __wt_logmgr_open --
* Start the log service threads.
*/
int
__wt_logmgr_open(WT_SESSION_IMPL *session)
{
WT_CONNECTION_IMPL *conn;
uint32_t session_flags;
conn = S2C(session);
/* If no log thread services are configured, we're done. */
if (!FLD_ISSET(conn->log_flags, WT_CONN_LOG_ENABLED))
return (0);
/*
* Start the log close thread. It is not configurable.
* If logging is enabled, this thread runs.
*/
session_flags = WT_SESSION_NO_DATA_HANDLES;
WT_RET(__wt_open_internal_session(conn,
"log-close-server", false, session_flags, &conn->log_file_session));
WT_RET(__wt_cond_alloc(conn->log_file_session,
"log close server", false, &conn->log_file_cond));
/*
* Start the log file close thread.
*/
WT_RET(__wt_thread_create(conn->log_file_session,
&conn->log_file_tid, __log_file_server, conn->log_file_session));
conn->log_file_tid_set = true;
/*
* Start the log write LSN thread. It is not configurable.
* If logging is enabled, this thread runs.
*/
WT_RET(__wt_open_internal_session(conn, "log-wrlsn-server",
false, session_flags, &conn->log_wrlsn_session));
WT_RET(__wt_cond_auto_alloc(conn->log_wrlsn_session,
"log write lsn server", false, 10000, WT_MILLION,
&conn->log_wrlsn_cond));
WT_RET(__wt_thread_create(conn->log_wrlsn_session,
&conn->log_wrlsn_tid, __log_wrlsn_server, conn->log_wrlsn_session));
conn->log_wrlsn_tid_set = true;
/*
* If a log server thread exists, the user may have reconfigured
* archiving or pre-allocation. Signal the thread. Otherwise the
* user wants archiving and/or allocation and we need to start up
* the thread.
*/
if (conn->log_session != NULL) {
WT_ASSERT(session, conn->log_cond != NULL);
WT_ASSERT(session, conn->log_tid_set == true);
__wt_cond_auto_signal(session, conn->log_cond);
} else {
/* The log server gets its own session. */
WT_RET(__wt_open_internal_session(conn,
"log-server", false, session_flags, &conn->log_session));
WT_RET(__wt_cond_auto_alloc(conn->log_session,
"log server", false, 50000, WT_MILLION, &conn->log_cond));
/*
* Start the thread.
*/
WT_RET(__wt_thread_create(conn->log_session,
&conn->log_tid, __log_server, conn->log_session));
conn->log_tid_set = true;
}
return (0);
}
/*
* __wt_logmgr_destroy --
* Destroy the log archiving server thread and logging subsystem.
*/
int
__wt_logmgr_destroy(WT_SESSION_IMPL *session)
{
WT_CONNECTION_IMPL *conn;
WT_DECL_RET;
WT_SESSION *wt_session;
conn = S2C(session);
if (!FLD_ISSET(conn->log_flags, WT_CONN_LOG_ENABLED)) {
/*
* We always set up the log_path so printlog can work without
* recovery. Therefore, always free it, even if logging isn't
* on.
*/
__wt_free(session, conn->log_path);
return (0);
}
if (conn->log_tid_set) {
__wt_cond_auto_signal(session, conn->log_cond);
WT_TRET(__wt_thread_join(session, conn->log_tid));
conn->log_tid_set = false;
}
if (conn->log_file_tid_set) {
__wt_cond_signal(session, conn->log_file_cond);
WT_TRET(__wt_thread_join(session, conn->log_file_tid));
conn->log_file_tid_set = false;
}
if (conn->log_file_session != NULL) {
wt_session = &conn->log_file_session->iface;
WT_TRET(wt_session->close(wt_session, NULL));
conn->log_file_session = NULL;
}
if (conn->log_wrlsn_tid_set) {
__wt_cond_auto_signal(session, conn->log_wrlsn_cond);
WT_TRET(__wt_thread_join(session, conn->log_wrlsn_tid));
conn->log_wrlsn_tid_set = false;
}
if (conn->log_wrlsn_session != NULL) {
wt_session = &conn->log_wrlsn_session->iface;
WT_TRET(wt_session->close(wt_session, NULL));
conn->log_wrlsn_session = NULL;
}
WT_TRET(__wt_log_slot_destroy(session));
WT_TRET(__wt_log_close(session));
/* Close the server thread's session. */
if (conn->log_session != NULL) {
wt_session = &conn->log_session->iface;
WT_TRET(wt_session->close(wt_session, NULL));
conn->log_session = NULL;
}
/* Destroy the condition variables now that all threads are stopped */
WT_TRET(__wt_cond_auto_destroy(session, &conn->log_cond));
WT_TRET(__wt_cond_destroy(session, &conn->log_file_cond));
WT_TRET(__wt_cond_auto_destroy(session, &conn->log_wrlsn_cond));
WT_TRET(__wt_cond_destroy(session, &conn->log->log_sync_cond));
WT_TRET(__wt_cond_destroy(session, &conn->log->log_write_cond));
__wt_rwlock_destroy(session, &conn->log->log_archive_lock);
__wt_spin_destroy(session, &conn->log->log_lock);
__wt_spin_destroy(session, &conn->log->log_slot_lock);
__wt_spin_destroy(session, &conn->log->log_sync_lock);
__wt_spin_destroy(session, &conn->log->log_writelsn_lock);
__wt_free(session, conn->log_path);
__wt_free(session, conn->log);
return (ret);
}
/*
* __logmgr_config --
* Parse and setup the logging server options.
*/
static int
__logmgr_config(
WT_SESSION_IMPL *session, const char **cfg, bool *runp, bool reconfig)
{
WT_CONFIG_ITEM cval;
WT_CONNECTION_IMPL *conn;
bool enabled;
/*
* A note on reconfiguration: the standard "is this configuration string
* allowed" checks should fail if reconfiguration has invalid strings,
* for example, "log=(enabled)", or "statistics_log=(path=XXX)", because
* the connection reconfiguration method doesn't allow those strings.
* Additionally, the base configuration values during reconfiguration
* are the currently configured values (so we don't revert to default
* values when repeatedly reconfiguring), and configuration processing
* of a currently set value should not change the currently set value.
*
* In this code path, log server reconfiguration does not stop/restart
* the log server, so there's no point in re-evaluating configuration
* strings that cannot be reconfigured, risking bugs in configuration
* setup, and depending on evaluation of currently set values to always
* result in the currently set value. Skip tests for any configuration
* strings which don't make sense during reconfiguration, but don't
* worry about error reporting because it should never happen.
*/
conn = S2C(session);
WT_RET(__wt_config_gets(session, cfg, "log.enabled", &cval));
enabled = cval.val != 0;
/*
* If we're reconfiguring, enabled must match the already
* existing setting.
*
* If it is off and the user it turning it on, or it is on
* and the user is turning it off, return an error.
*
* See above: should never happen.
*/
if (reconfig &&
((enabled && !FLD_ISSET(conn->log_flags, WT_CONN_LOG_ENABLED)) ||
(!enabled && FLD_ISSET(conn->log_flags, WT_CONN_LOG_ENABLED))))
WT_RET_MSG(session, EINVAL,
"log manager reconfigure: enabled mismatch with existing "
"setting");
/* Logging is incompatible with in-memory */
if (enabled) {
WT_RET(__wt_config_gets(session, cfg, "in_memory", &cval));
if (cval.val != 0)
WT_RET_MSG(session, EINVAL,
"In-memory configuration incompatible with "
"log=(enabled=true)");
}
*runp = enabled;
/*
* Setup a log path and compression even if logging is disabled in case
* we are going to print a log. Only do this on creation. Once a
* compressor or log path are set they cannot be changed.
*
* See above: should never happen.
*/
if (!reconfig) {
conn->log_compressor = NULL;
WT_RET(__wt_config_gets_none(
session, cfg, "log.compressor", &cval));
WT_RET(__wt_compressor_config(
session, &cval, &conn->log_compressor));
WT_RET(__wt_config_gets(session, cfg, "log.path", &cval));
WT_RET(__wt_strndup(
session, cval.str, cval.len, &conn->log_path));
}
/* We are done if logging isn't enabled. */
if (!*runp)
return (0);
WT_RET(__wt_config_gets(session, cfg, "log.archive", &cval));
if (cval.val != 0)
FLD_SET(conn->log_flags, WT_CONN_LOG_ARCHIVE);
/*
* The file size cannot be reconfigured. The amount of memory allocated
* to the log slots may be based on the log file size at creation and we
* don't want to re-allocate that memory while running.
*
* See above: should never happen.
*/
if (!reconfig) {
WT_RET(__wt_config_gets(session, cfg, "log.file_max", &cval));
conn->log_file_max = (wt_off_t)cval.val;
WT_STAT_CONN_SET(session, log_max_filesize, conn->log_file_max);
}
/*
* If pre-allocation is configured, set the initial number to a few.
* We'll adapt as load dictates.
*/
WT_RET(__wt_config_gets(session, cfg, "log.prealloc", &cval));
if (cval.val != 0)
conn->log_prealloc = 1;
/*
* Note it's meaningless to reconfigure this value during runtime, it
* only matters on create before recovery runs.
*
* See above: should never happen.
*/
if (!reconfig) {
WT_RET(__wt_config_gets_def(
session, cfg, "log.recover", 0, &cval));
if (WT_STRING_MATCH("error", cval.str, cval.len))
FLD_SET(conn->log_flags, WT_CONN_LOG_RECOVER_ERR);
}
WT_RET(__wt_config_gets(session, cfg, "log.zero_fill", &cval));
if (cval.val != 0) {
if (F_ISSET(conn, WT_CONN_READONLY))
WT_RET_MSG(session, EINVAL,
"Read-only configuration incompatible with "
"zero-filling log files");
FLD_SET(conn->log_flags, WT_CONN_LOG_ZERO_FILL);
}
WT_RET(__logmgr_sync_cfg(session, cfg));
if (conn->log_cond != NULL)
__wt_cond_auto_signal(session, conn->log_cond);
return (0);
}
