- scheduler: FCGI: use mysql_ping() to check that DB connection

is still alive before handling a request.  If not, try to reconnect.
    This will hopefully make things work better if MySQL goes down and up
    when using FCGI.

svn path=/trunk/boinc/; revision=16112

checkin_notes

@@ -7949,3 +7949,14 @@ Rom    2 Oct 2008
     
     cURL/
         <Various Files>
+
+David  2 Oct 2008
+    - scheduler: FCGI: use mysql_ping() to check that DB connection
+        is still alive before handling a request.  If not, try to reconnect.
+        This will hopefully make things work better if MySQL goes down and up
+        when using FCGI.
+
+    db/
+        db_base.cpp,h
+    sched/
+        main.cpp

db/db_base.cpp

@@ -125,6 +125,12 @@ int DB_CONN::rollback_transaction() {
 	return do_query("ROLLBACK");
 }
 
+int DB_CONN::ping() {
+    int retval = mysql_ping(mysql);
+    if (retval) return ERR_DB_CANT_CONNECT;
+    return 0;
+}
+
 DB_BASE::DB_BASE(const char *tn, DB_CONN* p) : db(p), table_name(tn) {
 }
 

db/db_base.h

@@ -75,11 +75,12 @@ public:
     int insert_id();
     void print_error(const char*);
     const char* error_string();
-
-    MYSQL* mysql;
+    int ping();
     int start_transaction();
     int rollback_transaction();
     int commit_transaction();
+
+    MYSQL* mysql;
 };
 
 // Base for derived classes that can access the DB

sched/main.cpp

@@ -167,15 +167,22 @@ static void send_message(const char* msg, int delay) {
 int open_database() {
     int retval;
 
-    if (db_opened) return 0;
+    if (db_opened) {
+        retval = boinc_db.ping();
+        if (retval) {
+            log_messages.printf(MSG_CRITICAL,
+                "lost connection to database - trying to reconnect\n"
+            );
+        } else {
+            return 0;
+        }
+    }
 
     retval = boinc_db.open(
         config.db_name, config.db_host, config.db_user, config.db_passwd
     );
     if (retval) {
-        log_messages.printf(MSG_CRITICAL,
-            "can't open database\n"
-        );
+        log_messages.printf(MSG_CRITICAL, "can't open database\n");
         return retval;
     }
     db_opened = true;
@@ -450,7 +457,7 @@ int main(int argc, char** argv) {
 #ifndef _USING_FCGI_
         fout = fopen(req_path, "w");
 #else
-	fout = FCGI::fopen(req_path,"w");
+        fout = FCGI::fopen(req_path,"w");
 #endif
         if (!fout) {
             log_messages.printf(MSG_CRITICAL,
@@ -471,7 +478,7 @@ int main(int argc, char** argv) {
 #ifndef _USING_FCGI_
         fin = fopen(req_path, "r");
 #else
-	fin = FCGI::fopen(req_path,"r");
+        fin = FCGI::fopen(req_path,"r");
 #endif
         if (!fin) {
             log_messages.printf(MSG_CRITICAL,