*** empty log message ***

svn path=/trunk/boinc/; revision=4088

checkin_notes

@@ -16554,3 +16554,27 @@ David  20 Aug 2004
 
     client/
         app_control.C
+
+David  20 Aug 2004
+    - already_sent_to_different_platform():
+        fix concurrency bug by reading WU.workseq_next
+        from database just prior to checking,
+        then updating the field immediately if needed.
+    - scheduler: update_wu_transition_time():
+        use update_field(); more efficient
+    - Added DB_BASE::get_field_int(): get a single integer
+        field from a DB record.
+        A little cheaper than reading the whole record
+    - DB_BASE::lookup(): remove code that sees if record is unique.
+        It's called after mysql_free_result(),
+        so it will never return anything.
+    - DB code: changed "if (db->mysql && is_high_priority) to just
+        "if (is_high_priority)".
+        db->mysql is a pointer, and is always nonzero.
+        It's not a flag saying whether the DB is MySQL.
+        All this code is only for MySQL anyway.
+
+    db/
+        db_base.C,h
+    sched/
+        sched_send.C

db/db_base.C

@@ -108,13 +108,31 @@ int DB_BASE::update_field(char* clause) {
     return db->do_query(query);
 }
 
+int DB_BASE::get_field_int(char* field, int& val) {
+    char query[MAX_QUERY_LEN];
+    int retval;
+    MYSQL_ROW row;
+    MYSQL_RES* rp;
+
+    sprintf(query, "select %s from %s where id=%d", field, table_name, get_id());
+    retval = db->do_query(query);
+    if (retval) return retval;
+    rp = mysql_store_result(db->mysql);
+    if (!rp) return -1;
+    row = mysql_fetch_row(rp);
+    if (row) val = atoi(row[0]);
+    mysql_free_result(rp);
+    if (row == 0) return ERR_DB_NOT_FOUND;
+    return 0;
+}
+
 int DB_BASE::lookup(char* clause) {
     char query[MAX_QUERY_LEN];
     int retval;
     MYSQL_ROW row;
     MYSQL_RES* rp;
 
-    if (db->mysql && is_high_priority) {
+    if (is_high_priority) {
         sprintf(query, "select HIGH_PRIORITY * from %s %s", table_name, clause);
     } else {
         sprintf(query, "select * from %s %s", table_name, clause);
@@ -128,11 +146,6 @@ int DB_BASE::lookup(char* clause) {
     if (row) db_parse(row);
     mysql_free_result(rp);
     if (row == 0) return ERR_DB_NOT_FOUND;
-
-    // make sure there's exactly one row
-    //
-    row = mysql_fetch_row(rp);
-    if (row) return ERR_DB_NOT_UNIQUE;
     return 0;
 }
 
@@ -142,7 +155,7 @@ int DB_BASE::lookup_id(int id) {
     MYSQL_ROW row;
     MYSQL_RES* rp;
 
-    if (db->mysql && is_high_priority) {
+    if (is_high_priority) {
         sprintf(query, "select HIGH_PRIORITY * from %s where id=%d", table_name, id);
     } else {
         sprintf(query, "select * from %s where id=%d", table_name, id);
@@ -169,7 +182,7 @@ int DB_BASE::enumerate(char* clause) {
     if (!cursor.active) {
         cursor.active = true;
 
-        if (db->mysql && is_high_priority) {
+        if (is_high_priority) {
             sprintf(query, "select HIGH_PRIORITY * from %s %s", table_name, clause);
         } else {
             sprintf(query, "select * from %s %s", table_name, clause);
@@ -242,7 +255,7 @@ int DB_BASE::get_double(char* query, double& x) {
 int DB_BASE::count(int& n, char* clause) {
     char query[MAX_QUERY_LEN];
 
-    if (db->mysql && is_high_priority) {
+    if (is_high_priority) {
         sprintf(query, "select HIGH_PRIORITY count(*) from %s %s", table_name, clause);
     } else {
         sprintf(query, "select count(*) from %s %s", table_name, clause);
@@ -254,7 +267,7 @@ int DB_BASE::count(int& n, char* clause) {
 int DB_BASE::sum(double& x, char* field, char* clause) {
     char query[MAX_QUERY_LEN];
 
-    if (db->mysql && is_high_priority) {
+    if (is_high_priority) {
         sprintf(query, "select HIGH_PRIORITY sum(%s) from %s %s", field, table_name, clause);
     } else {
         sprintf(query, "select sum(%s) from %s %s", field, table_name, clause);

db/db_base.h

@@ -82,6 +82,7 @@ public:
     int insert_batch(const char*);
     int update();
     int update_field(char*);
+    int get_field_int(char*, int&);
     int lookup_id(int id);
     int lookup(char*);
     int enumerate(char* clause="");

sched/sched_send.C

@@ -354,20 +354,13 @@ int insert_deadline_tag(RESULT& result) {
 }
 
 static int update_wu_transition_time(WORKUNIT wu, time_t x) {
-    // TODO: this might be better: a mysql statement such as "update set
-    // transition_time=X where id=ID and transition_time<X".  this avoids
-    // concurrency problems altogether.
     DB_WORKUNIT dbwu;
     int retval;
+    char buf[256];
 
-    retval = dbwu.lookup_id(wu.id);
-    if (retval) return retval;
-    if (x < dbwu.transition_time) {
-        dbwu.transition_time = x;
-        retval = dbwu.update();
-        if (retval) return retval;
-    }
-    return 0;
+    dbwu.id = wu.id;
+    sprintf(buf, "transition_time=%d", x);
+    return dbwu.update_field(buf);
 }
 
 // return true iff a result for same WU is already being sent
@@ -431,15 +424,30 @@ bool same_platform(DB_HOST& host, SCHEDULER_REQUEST& sreq) {
 static bool already_sent_to_different_platform(
     SCHEDULER_REQUEST& sreq, WORKUNIT& workunit, WORK_REQ& wreq
 ) {
+    DB_WORKUNIT db_wu;
+    int wsn;
+    char buf[256];
+
+    // reread workseq_next field from DB in case it's changed
+    //
+    db_wu.id = workunit.id;
+    retval = db_wu.get_field("workseq_next", wsn);
+    if (retval) {
+        log_messages.printf(
+            SCHED_MSG_LOG::ERROR, "can't get workseq_next for %s: %d\n",
+            dbwu.id, retval
+        );
+        return true;
+    }
     wreq.homogeneous_redundancy_reject = false;
-    if (workunit.workseq_next != unspec) {
-        if (OS(sreq) + CPU(sreq) != workunit.workseq_next)
+    if (wsn != unspec) {
+        if (OS(sreq) + CPU(sreq) != wsn) {
             wreq.homogeneous_redundancy_reject = true;
+        }
     } else {
-      workunit.workseq_next = OS(sreq) + CPU(sreq);
-      DB_WORKUNIT db_wu;
-      db_wu = workunit;
-      db_wu.update();
+        wsn = OS(sreq) + CPU(sreq);
+        sprintf(buf, "workseq_next=%d", wsn);
+        db_wu.update_field(buf);
     }
     return wreq.homogeneous_redundancy_reject;
 }