[GNUnet-SVN] r5157 - GNUnet/src/applications/sqstore_sqlite

[gnunet]

Author: grothoff
Date: 2007-06-28 00:44:20 -0600 (Thu, 28 Jun 2007)
New Revision: 5157

Modified:
   GNUnet/src/applications/sqstore_sqlite/sqlite.c
Log:
experimental real-time fix for sqlite code

Modified: GNUnet/src/applications/sqstore_sqlite/sqlite.c
===================================================================
--- GNUnet/src/applications/sqstore_sqlite/sqlite.c     2007-06-28 05:44:56 UTC 
(rev 5156)
+++ GNUnet/src/applications/sqstore_sqlite/sqlite.c     2007-06-28 06:44:20 UTC 
(rev 5157)
@@ -52,6 +52,18 @@
  */
 #define LOG_SQLITE(db, level, cmd) do { GE_LOG(ectx, level, _("`%s' failed at 
%s:%d with error: %s\n"), cmd, __FILE__, __LINE__, sqlite3_errmsg(db->dbh)); } 
while(0);
 
+/**
+ * After how many ms "busy" should a DB operation fail for good?
+ * A low value makes sure that we are more responsive to requests
+ * (especially PUTs).  A high value guarantees a higher success
+ * rate (SELECTs in iterate can take several seconds despite LIMIT=1).
+ *
+ * The default value of 250ms should ensure that users do not experience
+ * huge latencies while at the same time allowing operations to succeed
+ * with reasonable probability.
+ */
+#define BUSY_TIMEOUT_MS 250
+
 static Stats_ServiceAPI * stats;
 
 static CoreAPIForApplication * coreAPI;
@@ -211,6 +223,11 @@
   CHECK(SQLITE_OK ==
        sqlite3_exec(ret->dbh,
                     "PRAGMA page_size=4092", NULL, NULL, ENULL));
+  
+  CHECK(SQLITE_OK ==
+       sqlite3_busy_timeout(ret->dbh,
+                            BUSY_TIMEOUT_MS));
+  
 
   /* We have to do it here, because otherwise precompiling SQL might fail */
   CHECK(SQLITE_OK ==
@@ -444,6 +461,8 @@
     }
   }
   sqlite3_finalize(stmt);
+  if (i == SQLITE_BUSY) 
+    return SYSERR;
   if (i != SQLITE_OK) {
     LOG_SQLITE(handle,
               GE_ERROR | GE_ADMIN | GE_USER | GE_BULK,
@@ -547,8 +566,6 @@
 
   handle = getDBHandle();
   dbh = handle->dbh;
-  MUTEX_LOCK(db->DATABASE_Lock_);
-
   /* For the rowid trick see
       http://permalink.gmane.org/gmane.network.gnunet.devel/1363 */
   strcpy(scratch,
@@ -610,7 +627,6 @@
     LOG_SQLITE(handle,
               GE_ERROR | GE_ADMIN | GE_USER | GE_BULK,
               "sqlite3_prepare");
-    MUTEX_UNLOCK(db->DATABASE_Lock_);
     return SYSERR;
   }
   count    = 0;
@@ -688,16 +704,13 @@
           (ntohl(datum->value.anonymityLevel) == 0) ) {
        count++;
        if (iter != NULL) {
-         MUTEX_UNLOCK(db->DATABASE_Lock_);
          if (SYSERR == iter(&datum->key,
                             &datum->value,
                             closure) ) {
            FREE(datum);
-           MUTEX_LOCK(db->DATABASE_Lock_);
            count = SYSERR;
            break;
          }
-         MUTEX_LOCK(db->DATABASE_Lock_);
        }
       }
       key = datum->key;
@@ -710,7 +723,6 @@
                   GE_ERROR | GE_ADMIN | GE_USER | GE_BULK,
                   "sqlite_query");
        sqlite3_finalize(stmt);
-       MUTEX_UNLOCK(db->DATABASE_Lock_);
        return SYSERR;
       }
       sqlite3_reset(stmt);
@@ -718,8 +730,6 @@
     }
   }
   sqlite3_finalize(stmt);
-  MUTEX_UNLOCK(db->DATABASE_Lock_);
-
   return count;
 }
 
@@ -807,8 +817,6 @@
 
   handle = getDBHandle();
   dbh = handle->dbh;
-  MUTEX_LOCK(db->DATABASE_Lock_);
-
   /* For the rowid trick see
       http://permalink.gmane.org/gmane.network.gnunet.devel/1363 */
   if (sq_prepare(dbh,
@@ -817,7 +825,6 @@
     LOG_SQLITE(handle,
               GE_ERROR | GE_ADMIN | GE_USER | GE_BULK,
               "sqlite3_prepare");
-    MUTEX_UNLOCK(db->DATABASE_Lock_);
     return SYSERR;
   }
   count = 0;
@@ -843,12 +850,9 @@
               GE_ERROR | GE_ADMIN | GE_USER | GE_BULK,
               "sqlite_query");
     sqlite3_finalize(stmt);
-    MUTEX_UNLOCK(db->DATABASE_Lock_);
     return SYSERR;
   }
   sqlite3_finalize(stmt);
-  MUTEX_UNLOCK(db->DATABASE_Lock_);
-
   return count;
 }
 
@@ -940,8 +944,6 @@
 #endif
   handle = getDBHandle();
   dbh = handle->dbh;
-  MUTEX_LOCK(db->DATABASE_Lock_);
-
   strcpy(scratch, "SELECT ");
   if (iter == NULL)
     strcat(scratch, "count(*)");
@@ -967,7 +969,6 @@
     LOG_SQLITE(handle,
               GE_ERROR | GE_ADMIN | GE_USER | GE_BULK,
               "sqlite_query");
-    MUTEX_UNLOCK(db->DATABASE_Lock_);
     return SYSERR;
   }
 
@@ -1015,12 +1016,15 @@
       } else
        count += sqlite3_column_int(stmt, 0);
     }
+    if (ret == SQLITE_BUSY) {
+      sqlite3_finalize(stmt);
+      return count;
+    }
     if (ret != SQLITE_DONE) {
       LOG_SQLITE(handle,
                 GE_ERROR | GE_ADMIN | GE_USER | GE_BULK,
                 "sqlite_query");
       sqlite3_finalize(stmt);
-      MUTEX_UNLOCK(db->DATABASE_Lock_);
       return SYSERR;
     }
 
@@ -1030,8 +1034,6 @@
               GE_ERROR | GE_ADMIN | GE_USER | GE_BULK,
               "sqlite_query");
 
-  MUTEX_UNLOCK(db->DATABASE_Lock_);
-
 #if DEBUG_SQLITE
   GE_LOG(ectx,
         GE_DEBUG | GE_REQUEST | GE_USER,
@@ -1045,7 +1047,7 @@
  * Write content to the db.  Always adds a new record
  * (does NOT overwrite existing data).
  *
- * @return SYSERR on error, OK if ok.
+ * @return SYSERR on error, NO on temporary error, OK if ok.
  */
 static int put(const HashCode512 * key,
               const Datastore_Value * value) {
@@ -1076,7 +1078,6 @@
     return SYSERR;
   }
   dbh = getDBHandle();
-  MUTEX_LOCK(db->DATABASE_Lock_);
   if (db->lastSync > 1000)
     syncStats(dbh);
   contentSize = ntohl(value->size)-sizeof(Datastore_Value);
@@ -1095,17 +1096,19 @@
   sqlite3_bind_blob(stmt, 7, &value[1], contentSize, SQLITE_TRANSIENT);
   n = sqlite3_step(stmt);
   if (n != SQLITE_DONE) {
+    if (n == SQLITE_BUSY) {
+      sqlite3_reset(stmt);    
+      return NO;
+    }
     LOG_SQLITE(dbh,
               GE_ERROR | GE_ADMIN | GE_USER | GE_BULK,
               "sqlite_query");
-    sqlite3_reset(stmt);
-    MUTEX_UNLOCK(db->DATABASE_Lock_);
+    sqlite3_reset(stmt);    
     return SYSERR;
   }
   sqlite3_reset(stmt);
   db->lastSync++;
   db->payload += getContentDatastoreSize(value);
-  MUTEX_UNLOCK(db->DATABASE_Lock_);
 #if DEBUG_SQLITE
   GE_LOG(ectx,
         GE_DEBUG | GE_REQUEST | GE_USER,
@@ -1149,7 +1152,6 @@
 #endif
 
   dbh = getDBHandle();
-  MUTEX_LOCK(db->DATABASE_Lock_);
   if (db->lastSync > 1000)
     syncStats(dbh);
 
@@ -1161,7 +1163,6 @@
       LOG_SQLITE(dbh,
                 GE_ERROR | GE_ADMIN | GE_USER | GE_BULK,
                 "sqlite_query");
-      MUTEX_UNLOCK(db->DATABASE_Lock_);
       return SYSERR;
     }
     sqlite3_bind_blob(stmt,
@@ -1171,14 +1172,12 @@
                      SQLITE_TRANSIENT);
     if (sqlite3_step(stmt) != SQLITE_ROW) {
       sqlite3_finalize(stmt);
-      MUTEX_UNLOCK(db->DATABASE_Lock_);
       return NO;
     }
     dvalue = assembleDatum(dbh,
                           stmt);
     if (dvalue == NULL) {
       sqlite3_finalize(stmt);
-      MUTEX_UNLOCK(db->DATABASE_Lock_);
       return SYSERR;
     }
     sqlite3_finalize(stmt);
@@ -1222,11 +1221,9 @@
     LOG_SQLITE(dbh,
               GE_ERROR | GE_ADMIN | GE_USER | GE_BULK,
               "sqlite_query");
-    MUTEX_UNLOCK(db->DATABASE_Lock_);
     return SYSERR;
   }
   db->lastSync++;
-  MUTEX_UNLOCK(db->DATABASE_Lock_);
 
 #if DEBUG_SQLITE
   GE_LOG(ectx,
@@ -1263,7 +1260,6 @@
 #endif
 
   dbh = getDBHandle();
-  MUTEX_LOCK(db->DATABASE_Lock_);
   contentSize = ntohl(value->size)-sizeof(Datastore_Value);
   sqlite3_bind_int(dbh->updPrio,
                   1,
@@ -1291,14 +1287,13 @@
   n = sqlite3_step(dbh->updPrio);
   sqlite3_reset(dbh->updPrio);
 
-  MUTEX_UNLOCK(db->DATABASE_Lock_);
-
 #if DEBUG_SQLITE
   GE_LOG(ectx,
         GE_DEBUG | GE_REQUEST | GE_USER,
         "SQLite: block updated\n");
 #endif
-
+  if (n == SQLITE_BUSY) 
+    return NO;
   return n == SQLITE_OK ? OK : SYSERR;
 }