- server: DB update queries check that the number of affected rows is 1.

However, MySQL's default is that "affected rows" is
    rows actually modified, which is not what we want.
    Use the CLIENT_FOUND_ROWS option in mysql_real_connect()
    to change the semantics to "rows matched".
    From Oliver Bock.

svn path=/trunk/boinc/; revision=20880

checkin_notes

@@ -1919,3 +1919,14 @@ David  12 Mar 2010
 
     client/
         cpu_sched.cpp
+
+David  12 Mar 2010
+    - server: DB update queries check that the number of affected rows is 1.
+        However, MySQL's default is that "affected rows" is
+        rows actually modified, which is not what we want.
+        Use the CLIENT_FOUND_ROWS option in mysql_real_connect()
+        to change the semantics to "rows matched".
+        From Oliver Bock.
+
+    db/
+        db_base.cpp

db/db_base.cpp

@@ -70,8 +70,11 @@ int DB_CONN::open(char* db_name, char* db_host, char* db_user, char* dbpassword)
         my_bool mbReconnect = 1;
         mysql_options(mysql, MYSQL_OPT_RECONNECT, &mbReconnect);
     }
+    // CLIENT_FOUND_ROWS means that the # of affected rows for an update
+    // is the # matched by the where, rather than the # actually changed
+    //
     mysql = mysql_real_connect(
-        mysql, db_host, db_user, dbpassword, db_name, 0, 0, 0
+        mysql, db_host, db_user, dbpassword, db_name, 0, 0, CLIENT_FOUND_ROWS
     );
     if (mysql == 0) return ERR_DB_CANT_CONNECT;
 
@@ -122,6 +125,8 @@ int DB_CONN::do_query(const char* p) {
     return retval;
 }
 
+// returns the number of rows matched by an update query
+//
 int DB_CONN::affected_rows() {
     unsigned long x = (unsigned long)mysql_affected_rows(mysql);
     //fprintf(stderr, "x: %lu i: %d\n", x, (int)x);