Changeset: 5b1038e7ec5c for MonetDB
URL: http://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=5b1038e7ec5c
Modified Files:
common/utils/msabaoth.c
Branch: Jun2016
Log Message:
Fix race.
Move checking for scenario and connection until *after* establishing
that the server is actully up and running.
See bug 4066, comment 29.
diffs (174 lines):
diff --git a/common/utils/msabaoth.c b/common/utils/msabaoth.c
--- a/common/utils/msabaoth.c
+++ b/common/utils/msabaoth.c
@@ -594,6 +594,85 @@ msab_getSingleStatus(const char *pathbuf
sdb->path = strdup(buf);
sdb->dbname = sdb->path + strlen(sdb->path) - strlen(dbname);
+
+ /* check the state of the server by looking at its gdk lock:
+ * - if we can lock it, the server has crashed or isn't running
+ * - if we can't open it because it's locked, the server is
+ * running
+ * - to distinguish between a crash and proper shutdown, consult
+ * the uplog
+ * - one exception to all above; if this is the same process, we
+ * cannot lock (it always succeeds), hence, if we have the
+ * same signature, we assume running if the uplog states so.
+ */
+ snprintf(buf, sizeof(buf), "%s/%s/%s", pathbuf, dbname,
+ _sabaoth_internal_uuid);
+ if (stat(buf, &statbuf) != -1) {
+ /* database has the same process signature as ours, which
+ * means, it must be us, rely on the uplog state */
+ snprintf(log, sizeof(log), "%s/%s/%s", pathbuf, dbname,
UPLOGFILE);
+ if ((f = fopen(log, "r")) != NULL) {
+ (void)fseek(f, -1, SEEK_END);
+ if (fread(data, 1, 1, f) != 1) {
+ /* the log is empty, assume no crash */
+ sdb->state = SABdbInactive;
+ } else if (data[0] == '\t') {
+ /* see if the database has finished starting */
+ snprintf(buf, sizeof(buf), "%s/%s/%s",
+ pathbuf, dbname, STARTEDFILE);
+ if (stat(buf, &statbuf) == -1) {
+ sdb->state = SABdbStarting;
+ } else {
+ sdb->state = SABdbRunning;
+ }
+ } else { /* should be \n */
+ sdb->state = SABdbInactive;
+ }
+ (void)fclose(f);
+ }
+ } else if ((snprintf(buf, sizeof(buf), "%s/%s/%s", pathbuf, dbname,
".gdk_lock") > 0) & /* no typo */
+ ((fd = MT_lockf(buf, F_TEST, 4, 1)) == -2)) {
+ /* Locking failed; this can be because the lockfile couldn't
+ * be created. Probably there is no Mserver running for
+ * that case also.
+ */
+ sdb->state = SABdbInactive;
+ } else if (fd == -1) {
+ /* file is locked, so mserver is running, see if the database
+ * has finished starting */
+ snprintf(buf, sizeof(buf), "%s/%s/%s",
+ pathbuf, dbname, STARTEDFILE);
+ if (stat(buf, &statbuf) == -1) {
+ sdb->state = SABdbStarting;
+ } else {
+ sdb->state = SABdbRunning;
+ }
+ } else {
+ /* file is not locked, check for a crash in the uplog */
+ snprintf(log, sizeof(log), "%s/%s/%s", pathbuf, dbname,
UPLOGFILE);
+ if ((f = fopen(log, "r")) != NULL) {
+ (void)fseek(f, -1, SEEK_END);
+ if (fread(data, 1, 1, f) != 1) {
+ /* the log is empty, assume no crash */
+ sdb->state = SABdbInactive;
+ } else if (data[0] == '\n') {
+ sdb->state = SABdbInactive;
+ } else { /* should be \t */
+ sdb->state = SABdbCrashed;
+ }
+ (void)fclose(f);
+ } else {
+ /* no uplog, so presumably never started */
+ sdb->state = SABdbInactive;
+ }
+ }
+ snprintf(buf, sizeof(buf), "%s/%s/%s", pathbuf, dbname,
MAINTENANCEFILE);
+ if (stat(buf, &statbuf) == -1) {
+ sdb->locked = 0;
+ } else {
+ sdb->locked = 1;
+ }
+
/* add scenarios that are supported */
sdb->scens = NULL;
snprintf(buf, sizeof(buf), "%s/%s/%s", pathbuf, dbname, SCENARIOFILE);
@@ -638,84 +717,6 @@ msab_getSingleStatus(const char *pathbuf
(void)fclose(f);
}
-
- /* check the state of the server by looking at its gdk lock:
- * - if we can lock it, the server has crashed or isn't running
- * - if we can't open it because it's locked, the server is
- * running
- * - to distinguish between a crash and proper shutdown, consult
- * the uplog
- * - one exception to all above; if this is the same process, we
- * cannot lock (it always succeeds), hence, if we have the
- * same signature, we assume running if the uplog states so.
- */
- snprintf(buf, sizeof(buf), "%s/%s/%s", pathbuf, dbname,
- _sabaoth_internal_uuid);
- if (stat(buf, &statbuf) != -1) {
- /* database has the same process signature as ours, which
- * means, it must be us, rely on the uplog state */
- snprintf(log, sizeof(log), "%s/%s/%s", pathbuf, dbname,
UPLOGFILE);
- if ((f = fopen(log, "r")) != NULL) {
- (void)fseek(f, -1, SEEK_END);
- if (fread(data, 1, 1, f) != 1) {
- /* the log is empty, assume no crash */
- sdb->state = SABdbInactive;
- } else if (data[0] == '\t') {
- /* see if the database has finished starting */
- snprintf(buf, sizeof(buf), "%s/%s/%s",
- pathbuf, dbname, STARTEDFILE);
- if (stat(buf, &statbuf) == -1) {
- sdb->state = SABdbStarting;
- } else {
- sdb->state = SABdbRunning;
- }
- } else { /* should be \n */
- sdb->state = SABdbInactive;
- }
- (void)fclose(f);
- }
- } else if ((snprintf(buf, sizeof(buf), "%s/%s/%s", pathbuf, dbname,
".gdk_lock") > 0) & /* no typo */
- ((fd = MT_lockf(buf, F_TEST, 4, 1)) == -2)) {
- /* Locking failed; this can be because the lockfile couldn't
- * be created. Probably there is no Mserver running for
- * that case also.
- */
- sdb->state = SABdbInactive;
- } else if (fd == -1) {
- /* lock denied, so mserver is running, see if the database
- * has finished starting */
- snprintf(buf, sizeof(buf), "%s/%s/%s",
- pathbuf, dbname, STARTEDFILE);
- if (stat(buf, &statbuf) == -1) {
- sdb->state = SABdbStarting;
- } else {
- sdb->state = SABdbRunning;
- }
- } else {
- /* locking succeed, check for a crash in the uplog */
- snprintf(log, sizeof(log), "%s/%s/%s", pathbuf, dbname,
UPLOGFILE);
- if ((f = fopen(log, "r")) != NULL) {
- (void)fseek(f, -1, SEEK_END);
- if (fread(data, 1, 1, f) != 1) {
- /* the log is empty, assume no crash */
- sdb->state = SABdbInactive;
- } else if (data[0] == '\n') {
- sdb->state = SABdbInactive;
- } else { /* should be \t */
- sdb->state = SABdbCrashed;
- }
- (void)fclose(f);
- } else {
- /* no uplog, so presumably never started */
- sdb->state = SABdbInactive;
- }
- }
- snprintf(buf, sizeof(buf), "%s/%s/%s", pathbuf, dbname,
MAINTENANCEFILE);
- if (stat(buf, &statbuf) == -1) {
- sdb->locked = 0;
- } else {
- sdb->locked = 1;
- }
return sdb;
}
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