possible fix for db crashes, queue queries

Manos Chorianopoulos
Commit fb2276e6684a76191cfbdace0c2fd93d7d345d71 fb2276e6 1 parent 60f82088
Showing 1 changed file with 113 additions and 0 deletions
SwiftWarplyFramework/SwiftWarplyFramework/Warply/Warply.m
--- a/SwiftWarplyFramework/SwiftWarplyFramework/Warply/Warply.m
View file @fb2276e
+++ b/SwiftWarplyFramework/SwiftWarplyFramework/Warply/Warply.m
View file @fb2276e
@@ -81,6 +81,7 @@ typedef void (^FailureResponse)(NSURLSessionDataTask * _Nullable task, NSError *
 @property (nonatomic, strong) AFHTTPSessionManager *httpClient;
 @property (nonatomic) AFNetworkReachabilityStatus networkStatus;
 @property (nonatomic) BOOL hasChangedReachabilityStatus;
+@property (nonatomic, retain) NSString *DatabaseLock;
 - (id)initWithApplicationUUID:(NSString *)appUUID;
 - (BOOL)isRegistrationValid;
@@ -284,6 +285,8 @@ typedef void (^FailureResponse)(NSURLSessionDataTask * _Nullable task, NSError *
         [defaults synchronize];
         _pendingOperationsQueue = [[NSOperationQueue alloc] init];
         _pendingOperationsQueue.maxConcurrentOperationCount = 1;
+        
+        _DatabaseLock = @"Database-Lock";
     }
     return self;
 }
@@ -560,8 +563,10 @@ WL_VERSION_IMPLEMENTATION(WL_VERSION)
     [self.locationManager applicationDidEnterBackground];
     [WLAnalyticsManager logAppDidEnterBackgroundEvent];
     [self calculateNetworkReachabilityStatisticsForStatus:self.networkStatus];
+    @synchronized (_DatabaseLock) {
     [_db executeUpdate:@"PRAGMA shrink_memory"];
     WL_FMDBLogError
+    }
 }
 #pragma mark - Inbox
@@ -702,11 +707,13 @@ WL_VERSION_IMPLEMENTATION(WL_VERSION)
     NSString *accessToken = @"";
     if ([_db tableExists:@"requestVariables"] == YES) {
         @try {
+            @synchronized (_DatabaseLock) {
             FMResultSet *accessTokenSet = [_db executeQuery:@"SELECT access_token FROM requestVariables WHERE id = 1;"];
             while ([accessTokenSet next]) {
               accessToken = [[accessTokenSet resultDictionary][@"access_token"] stringValue];
             }
             }
+        }
         @catch (NSException *exception) {
            NSLog(@"SELECT accessToken error: %@", exception.reason);
             accessToken = @"";
@@ -729,11 +736,13 @@ WL_VERSION_IMPLEMENTATION(WL_VERSION)
     NSString *refreshToken = @"";
     if ([_db tableExists:@"requestVariables"] == YES) {
         @try {
+            @synchronized (_DatabaseLock) {
             FMResultSet *refreshTokenSet = [_db executeQuery:@"SELECT refresh_token FROM requestVariables WHERE id = 1;"];
             while ([refreshTokenSet next]) {
                 refreshToken = [[refreshTokenSet resultDictionary][@"refresh_token"] stringValue];
             }
             }
+        }
         @catch (NSException *exception) {
            NSLog(@"SELECT refreshToken error: %@", exception.reason);
             refreshToken = @"";
@@ -756,11 +765,13 @@ WL_VERSION_IMPLEMENTATION(WL_VERSION)
     NSString *clientId = @"";
     if ([_db tableExists:@"requestVariables"] == YES) {
         @try {
+            @synchronized (_DatabaseLock) {
             FMResultSet *clientIdSet = [_db executeQuery:@"SELECT client_id FROM requestVariables WHERE id = 1;"];
             while ([clientIdSet next]) {
                 clientId = [[clientIdSet resultDictionary][@"client_id"] stringValue];
             }
             }
+        }
         @catch (NSException *exception) {
            NSLog(@"SELECT clientId error: %@", exception.reason);
             clientId = @"";
@@ -783,11 +794,13 @@ WL_VERSION_IMPLEMENTATION(WL_VERSION)
     NSString *clientSecret = @"";
     if ([_db tableExists:@"requestVariables"] == YES) {
         @try {
+            @synchronized (_DatabaseLock) {
             FMResultSet *clientSecretSet = [_db executeQuery:@"SELECT client_secret FROM requestVariables WHERE id = 1;"];
             while ([clientSecretSet next]) {
                 clientSecret = [[clientSecretSet resultDictionary][@"client_secret"] stringValue];
             }
             }
+        }
         @catch (NSException *exception) {
            NSLog(@"SELECT clientSecret error: %@", exception.reason);
             clientSecret = @"";
@@ -945,15 +958,26 @@ WL_VERSION_IMPLEMENTATION(WL_VERSION)
             refreshToken = [contextResponse objectForKey:@"refresh_token"];
             NSString* accessToken = [NSString alloc];
             accessToken = [contextResponse objectForKey:@"access_oken"];
+//            @synchronized (_DatabaseLock) {
+//                
+//            }
+            @synchronized (_DatabaseLock) {
             [_db executeUpdate:@"DROP TABLE requestVariables"];
+            }
             if ([_db tableExists:@"requestVariables"] == NO) {
+                @synchronized (_DatabaseLock) {
                 [_db executeUpdate:@"CREATE TABLE requestVariables (id INTEGER PRIMARY KEY  AUTOINCREMENT  NOT NULL  UNIQUE, client_id INTEGER, client_secret VARCHAR(255), access_token VARCHAR(255), refresh_token VARCHAR(255))"];
                 WL_FMDBLogError
+                }
+                @synchronized (_DatabaseLock) {
                 [_db executeUpdate:@"INSERT INTO requestVariables (id, client_id, client_secret, refresh_token, access_token) VALUES (1, ?, ?, ?, ?)", clientId, clientSecret, refreshToken, accessToken];
+                }
             } else {
+                @synchronized (_DatabaseLock) {
               [_db executeUpdate:@"UPDATE requestVariables SET client_id = ? , client_secret = ?, refresh_token = ?, access_token = ? WHERE id = 1", clientId, clientSecret, refreshToken, accessToken];
                 }
+            }
             success(contextResponse);
         }
     } failureBlock:^(NSError *error) {
@@ -1013,7 +1037,9 @@ WL_VERSION_IMPLEMENTATION(WL_VERSION)
 - (NSDictionary*)logout
 {
+    @synchronized (_DatabaseLock) {
     [_db executeUpdate:@"DROP TABLE requestVariables"];
+    }
     NSDictionary *successResponse = @{@"result": @"success", @"status":@1};
     NSLog(@"**************** WARPLY Logout *****************" );
     return successResponse;
@@ -1026,15 +1052,23 @@ WL_VERSION_IMPLEMENTATION(WL_VERSION)
       clientId = [contextResponse objectForKey:@"client_id"];
       NSString* clientSecret = [NSString alloc];
       clientSecret = [contextResponse objectForKey:@"client_secret"];
+      @synchronized (_DatabaseLock) {
       [_db executeUpdate:@"DROP TABLE requestVariables"];
+      }
       if ([_db tableExists:@"requestVariables"] == NO) {
+          @synchronized (_DatabaseLock) {
           [_db executeUpdate:@"CREATE TABLE requestVariables (id INTEGER PRIMARY KEY  AUTOINCREMENT  NOT NULL  UNIQUE, client_id INTEGER, client_secret VARCHAR(255), access_token VARCHAR(255), refresh_token VARCHAR(255))"];
           WL_FMDBLogError
+          }
+          @synchronized (_DatabaseLock) {
           [_db executeUpdate:@"INSERT INTO requestVariables (id, client_id, client_secret) VALUES (1, ?, ?)", clientId, clientSecret];
+          }
       } else {
+          @synchronized (_DatabaseLock) {
         [_db executeUpdate:@"UPDATE requestVariables SET client_id = ? , client_secret = ? WHERE id = 1", clientId, clientSecret];
           }
+      }
       NSDictionary *postDictionary2 = [NSDictionary alloc];
       if ([loginType isEqual:@"email"]) {
           postDictionary2 = @{@"app_id": [contextResponse objectForKey:@"app_id"], @"client_id": clientId, @"confirm": @"yes", @"email":id, @"response_type":@"code", @"scope": [loginType stringByAppendingString:@" app_id"] };
@@ -1064,7 +1098,9 @@ WL_VERSION_IMPLEMENTATION(WL_VERSION)
   NSData *jsonData3 = [NSJSONSerialization dataWithJSONObject:postDictionary3 options:0 error:NULL];
   [self sendContext5:jsonData3 successBlock:^(NSDictionary *contextResponse) {
       if (success) {
+        @synchronized (_DatabaseLock) {
         [_db executeUpdate:@"UPDATE requestVariables SET access_token = ?, refresh_token = ? WHERE id = 1", [contextResponse objectForKey:@"access_token"], [contextResponse objectForKey:@"refresh_token"]];
+        }
         NSDictionary *successResponse = @{@"result": @"success", @"status":@1};
         success(successResponse);
       }
@@ -1123,8 +1159,10 @@ WL_VERSION_IMPLEMENTATION(WL_VERSION)
 - (void)updateRefreshTokenW:(NSString*)access_token :(NSString*)refresh_token
 {
     if ([_db tableExists:@"requestVariables"] == YES) {
+        @synchronized (_DatabaseLock) {
         [_db executeUpdate:@"UPDATE requestVariables SET access_token = ?, refresh_token = ? WHERE id = 1", access_token, refresh_token];
         }
+    }
 }
 - (void)refreshToken:(void(^)(NSDictionary *response))success failureBlock:(void(^)(NSError *error))failure
@@ -1135,17 +1173,22 @@ WL_VERSION_IMPLEMENTATION(WL_VERSION)
         NSString *clientSecret = @"";
         @try {
+            @synchronized (_DatabaseLock) {
             FMResultSet *refreshTokenSet = [_db executeQuery:@"SELECT refresh_token FROM requestVariables WHERE id = 1;"];
     //        NSString *refreshToken = @"";
             while ([refreshTokenSet next]) {
                 refreshToken = [[refreshTokenSet resultDictionary][@"refresh_token"] stringValue];
             }
+            }
+            @synchronized (_DatabaseLock) {
             FMResultSet *clientIdSet = [_db executeQuery:@"SELECT client_id FROM requestVariables WHERE id = 1;"];
     //        NSString *clientId = [NSString alloc];
     //        NSString *clientId = @"";
             while ([clientIdSet next]) {
                 clientId = [[clientIdSet resultDictionary][@"client_id"] stringValue];
             }
+            }
+            @synchronized (_DatabaseLock) {
             FMResultSet *clientSecretSet = [_db executeQuery:@"SELECT client_secret FROM requestVariables WHERE id = 1;"];
     //        NSString *clientSecret = [NSString alloc];
     //        NSString *clientSecret = @"";
@@ -1153,6 +1196,7 @@ WL_VERSION_IMPLEMENTATION(WL_VERSION)
                 clientSecret = [[clientSecretSet resultDictionary][@"client_secret"] stringValue];
             }
             }
+        }
         @catch (NSException *exception) {
            NSLog(@"SELECT Token error: %@", exception.reason);
             if (failure) {
@@ -1174,7 +1218,9 @@ WL_VERSION_IMPLEMENTATION(WL_VERSION)
 //                success(successResponse);
                 @try {
+                    @synchronized (_DatabaseLock) {
                     [_db executeUpdate:@"UPDATE requestVariables SET access_token = ?, refresh_token = ? WHERE id = 1", [contextResponse objectForKey:@"access_token"], [contextResponse objectForKey:@"refresh_token"]];
+                    }
                     NSDictionary *successResponse = @{@"result": @"success", @"status":@1};
                     success(successResponse);
                 }
@@ -1223,17 +1269,22 @@ WL_VERSION_IMPLEMENTATION(WL_VERSION)
         NSString *clientSecret = @"";
         @try {
+            @synchronized (_DatabaseLock) {
             FMResultSet *refreshTokenSet = [_db executeQuery:@"SELECT refresh_token FROM requestVariables WHERE id = 1;"];
     //        NSString *refreshToken = @"";
             while ([refreshTokenSet next]) {
                 refreshToken = [[refreshTokenSet resultDictionary][@"refresh_token"] stringValue];
             }
+            }
+            @synchronized (_DatabaseLock) {
             FMResultSet *clientIdSet = [_db executeQuery:@"SELECT client_id FROM requestVariables WHERE id = 1;"];
     //        NSString *clientId = [NSString alloc];
     //        NSString *clientId = @"";
             while ([clientIdSet next]) {
                 clientId = [[clientIdSet resultDictionary][@"client_id"] stringValue];
             }
+            }
+            @synchronized (_DatabaseLock) {
             FMResultSet *clientSecretSet = [_db executeQuery:@"SELECT client_secret FROM requestVariables WHERE id = 1;"];
     //        NSString *clientSecret = [NSString alloc];
     //        NSString *clientSecret = @"";
@@ -1241,6 +1292,7 @@ WL_VERSION_IMPLEMENTATION(WL_VERSION)
                 clientSecret = [[clientSecretSet resultDictionary][@"client_secret"] stringValue];
             }
             }
+        }
         @catch (NSException *exception) {
            NSLog(@"SELECT Token error: %@", exception.reason);
             if (failure) {
@@ -1261,7 +1313,9 @@ WL_VERSION_IMPLEMENTATION(WL_VERSION)
 //              success(successResponse);
                 @try {
+                    @synchronized (_DatabaseLock) {
                     [_db executeUpdate:@"UPDATE requestVariables SET access_token = ?, refresh_token = ? WHERE id = 1", [contextResponse objectForKey:@"access_token"], [contextResponse objectForKey:@"refresh_token"]];
+                    }
                     NSDictionary *successResponse = @{@"result": @"success", @"status":@1};
                     success(successResponse);
                 }
@@ -1310,17 +1364,22 @@ WL_VERSION_IMPLEMENTATION(WL_VERSION)
         NSString *clientSecret = @"";
         @try {
+            @synchronized (_DatabaseLock) {
             FMResultSet *refreshTokenSet = [_db executeQuery:@"SELECT refresh_token FROM requestVariables WHERE id = 1;"];
     //        NSString *refreshToken = @"";
             while ([refreshTokenSet next]) {
                 refreshToken = [[refreshTokenSet resultDictionary][@"refresh_token"] stringValue];
             }
+            }
+            @synchronized (_DatabaseLock) {
             FMResultSet *clientIdSet = [_db executeQuery:@"SELECT client_id FROM requestVariables WHERE id = 1;"];
     //        NSString *clientId = [NSString alloc];
     //        NSString *clientId = @"";
             while ([clientIdSet next]) {
                 clientId = [[clientIdSet resultDictionary][@"client_id"] stringValue];
             }
+            }
+            @synchronized (_DatabaseLock) {
             FMResultSet *clientSecretSet = [_db executeQuery:@"SELECT client_secret FROM requestVariables WHERE id = 1;"];
     //        NSString *clientSecret = [NSString alloc];
     //        NSString *clientSecret = @"";
@@ -1328,6 +1387,7 @@ WL_VERSION_IMPLEMENTATION(WL_VERSION)
                 clientSecret = [[clientSecretSet resultDictionary][@"client_secret"] stringValue];
             }
             }
+        }
         @catch (NSException *exception) {
            NSLog(@"SELECT Token error: %@", exception.reason);
             if (failure) {
@@ -1348,7 +1408,9 @@ WL_VERSION_IMPLEMENTATION(WL_VERSION)
 //              success(successResponse);
                 @try {
+                    @synchronized (_DatabaseLock) {
                     [_db executeUpdate:@"UPDATE requestVariables SET access_token = ?, refresh_token = ? WHERE id = 1", [contextResponse objectForKey:@"access_token"], [contextResponse objectForKey:@"refresh_token"]];
+                    }
                     NSDictionary *successResponse = @{@"result": @"success", @"status":@1};
                     success(successResponse);
                 }
@@ -1376,8 +1438,10 @@ WL_VERSION_IMPLEMENTATION(WL_VERSION)
       //         } failureBlock:^(NSError *error) {
                 if (failure) {
                     if ([_db tableExists:@"requestVariables"] == YES) {
+                        @synchronized (_DatabaseLock) {
                         [_db executeUpdate:@"DROP TABLE requestVariables"];
                         }
+                    }
                   failure(error);
                 }
                 NSLog(@"Error at token %@", error );
@@ -1997,11 +2061,17 @@ WL_VERSION_IMPLEMENTATION(WL_VERSION)
       accessToken = [tokens objectForKey:@"access_token"];
       NSString* clientSecret = [NSString alloc];
       clientSecret = [tokens objectForKey:@"client_secret"];
+    @synchronized (_DatabaseLock) {
       [_db executeUpdate:@"DROP TABLE requestVariables"];
+    }
+    @synchronized (_DatabaseLock) {
       [_db executeUpdate:@"CREATE TABLE requestVariables (id INTEGER PRIMARY KEY  AUTOINCREMENT  NOT NULL  UNIQUE, client_id INTEGER, client_secret VARCHAR(255), access_token VARCHAR(255), refresh_token VARCHAR(255))"];
       WL_FMDBLogError
+    }
+    @synchronized (_DatabaseLock) {
       [_db executeUpdate:@"INSERT INTO requestVariables (id, client_id, client_secret, access_token, refresh_token) VALUES (1, ?, ?, ?, ?)", clientId, clientSecret, accessToken, refreshToken];
+    }
         NSNumber* status = [NSNumber alloc];
         status = [contextResponse objectForKey:@"result"];
@@ -2038,11 +2108,17 @@ WL_VERSION_IMPLEMENTATION(WL_VERSION)
       accessToken = [tokens objectForKey:@"access_token"];
       NSString* clientSecret = [NSString alloc];
       clientSecret = [tokens objectForKey:@"client_secret"];
+    @synchronized (_DatabaseLock) {
       [_db executeUpdate:@"DROP TABLE requestVariables"];
+    }
+    @synchronized (_DatabaseLock) {
       [_db executeUpdate:@"CREATE TABLE requestVariables (id INTEGER PRIMARY KEY  AUTOINCREMENT  NOT NULL  UNIQUE, client_id INTEGER, client_secret VARCHAR(255), access_token VARCHAR(255), refresh_token VARCHAR(255))"];
       WL_FMDBLogError
+    }
+    @synchronized (_DatabaseLock) {
       [_db executeUpdate:@"INSERT INTO requestVariables (id, client_id, client_secret, access_token, refresh_token) VALUES (1, ?, ?, ?, ?)", clientId, clientSecret, accessToken, refreshToken];
+    }
       NSDictionary *successResponse = @{@"result": @"success", @"status":@1};
       if (success) {
@@ -3654,7 +3730,9 @@ return appIsRegisteredWithWarply;
 - (void)addEvent:(WLEvent *)event priority:(BOOL)priority
 {
     NSData *jsonData = [NSJSONSerialization dataWithJSONObject:event.data options:0 error:NULL];
+    @synchronized (_DatabaseLock) {
     [_db executeUpdate:@"INSERT INTO events (_id, type, time, data, priority) VALUES (NULL, ?, ?, ?, ?)", [event getType], event.time, jsonData, [NSNumber numberWithBool:priority]];
+    }
     [self sendEventsIfNeeded];
 }
@@ -3710,7 +3788,9 @@ return appIsRegisteredWithWarply;
         [self sendContext2:jsonAnalytics path:@"analytics" successBlock:^(NSDictionary *contextResponse) {
             if(deleteSql){
                 NSString *queryString = [NSString stringWithFormat:@"DELETE FROM events WHERE _id IN (%@)", commaSeperatedIds];
+                @synchronized (_DatabaseLock) {
                 [_db executeUpdate:queryString];
+                }
                 if ([_db hadError]) {
                     NSLog(@"Err %d: %@", [_db lastErrorCode], [_db lastErrorMessage]);
@@ -3739,7 +3819,9 @@ return appIsRegisteredWithWarply;
         [self sendContext2:jsonDevice path:@"deviceInfo" successBlock:^(NSDictionary *contextResponse) {
             if(deleteSql){
                 NSString *queryString = [NSString stringWithFormat:@"DELETE FROM events WHERE _id IN (%@)", commaSeperatedIds];
+                @synchronized (_DatabaseLock) {
                 [_db executeUpdate:queryString];
+                }
                 if ([_db hadError]) {
                     NSLog(@"Err %d: %@", [_db lastErrorCode], [_db lastErrorMessage]);
@@ -3768,7 +3850,9 @@ return appIsRegisteredWithWarply;
         [self sendContext2:jsonOther path:nil successBlock:^(NSDictionary *contextResponse) {
             if(deleteSql){
                 NSString *queryString = [NSString stringWithFormat:@"DELETE FROM events WHERE _id IN (%@)", commaSeperatedIds];
+                @synchronized (_DatabaseLock) {
                 [_db executeUpdate:queryString];
+                }
                 if ([_db hadError]) {
                     NSLog(@"Err %d: %@", [_db lastErrorCode], [_db lastErrorMessage]);
@@ -3816,6 +3900,7 @@ return appIsRegisteredWithWarply;
 -(BOOL)checkIfUserLoactionIsInPois:(CLLocation *) location {
 //    NSString *locationQuery = [NSString stringWithFormat:@"SELECT * FROM (SELECT distance(lat, lon, %@, %@) as distance, * FROM pois) WHERE distance < pois.radius", [NSNumber numberWithDouble:location.coordinate.latitude], [NSNumber numberWithDouble:location.coordinate.longitude]];
+    @synchronized (_DatabaseLock) {
     FMResultSet *result = [_db executeQuery:@"SELECT * FROM pois"];
     if (result == nil) return false;
@@ -3831,6 +3916,7 @@ return appIsRegisteredWithWarply;
             return true;
         }
     }
+    }
     return false;
 }
@@ -3852,8 +3938,10 @@ CGFloat DistanceBetweenTwoPoints(CGPoint point1,CGPoint point2)
 //            _db remove
             for (NSDictionary *poisDict in [contextResponse valueForKeyPath:@"MAPP_GEOFENCING"]) {
                 NSString *query = [NSString stringWithFormat: @"INSERT INTO pois (id, lat, lon, radius) VALUES (%@, %@, %@, %@)", [poisDict valueForKeyPath:@"id"], [poisDict valueForKeyPath:@"lat"], [poisDict valueForKeyPath:@"long"], [poisDict valueForKeyPath:@"radius"]];
+                @synchronized (_DatabaseLock) {
                 [_db executeUpdate: query];
                 }
+            }
 //            [[self locationManager] sendLocation:[self locationManager].locationManager.location];
         }
@@ -4696,11 +4784,13 @@ CGFloat DistanceBetweenTwoPoints(CGPoint point1,CGPoint point2)
     //     accessToken = [[accessTokenSet resultDictionary][@"access_token"] stringValue];
     //   }
     @try {
+        @synchronized (_DatabaseLock) {
             FMResultSet *accessTokenSet = [_db executeQuery:@"SELECT access_token FROM requestVariables WHERE id = 1;"];
             while ([accessTokenSet next]) {
               accessToken = [[accessTokenSet resultDictionary][@"access_token"] stringValue];
             }
         }
+        }
         @catch (NSException *exception) {
            NSLog(@"SELECT accessToken error: %@", exception.reason);
             if (failureBlock) {
@@ -4851,11 +4941,13 @@ CGFloat DistanceBetweenTwoPoints(CGPoint point1,CGPoint point2)
     NSString *accessToken = @"";
     if ([_db tableExists:@"requestVariables"] == YES) {
         @try {
+            @synchronized (_DatabaseLock) {
             FMResultSet *accessTokenSet = [_db executeQuery:@"SELECT access_token FROM requestVariables WHERE id = 1;"];
             while ([accessTokenSet next]) {
               accessToken = [[accessTokenSet resultDictionary][@"access_token"] stringValue];
             }
             }
+        }
         @catch (NSException *exception) {
            NSLog(@"SELECT accessToken error: %@", exception.reason);
             if (failureBlock) {
@@ -6461,23 +6553,32 @@ CGFloat DistanceBetweenTwoPoints(CGPoint point1,CGPoint point2)
 {
     if ([_db tableExists:@"events"] == YES && [_db tableExists:@"netstats"] == YES) {
         if ([_db columnExists:@"priority" inTableWithName:@"events"] == NO) {
+            
+            @synchronized (_DatabaseLock) {
             [_db executeUpdate:@"ALTER TABLE events ADD COLUMN priority INTEGER"];
             WL_FMDBLogError
             }
+        }
+        @synchronized (_DatabaseLock) {
         [_db executeUpdate:@"VACUUM"];
         WL_FMDBLogError
+        }
         return;
     }
     if ([_db tableExists:@"events"] == NO) {
+        @synchronized (_DatabaseLock) {
         [_db executeUpdate:@"CREATE TABLE events (_id INTEGER PRIMARY KEY  AUTOINCREMENT  NOT NULL  UNIQUE, type VARCHAR(255), time VARCHAR(255), data BLOB, priority INTEGER)"];
         WL_FMDBLogError
+        }
     } else if ([_db columnExists:@"priority" inTableWithName:@"events"] == NO) {
+        @synchronized (_DatabaseLock) {
         [_db executeUpdate:@"ALTER TABLE events ADD COLUMN priority INTEGER"];
         WL_FMDBLogError
         }
+    }
 //    if ([_db tableExists:@"netstats"] == NO) {
 //        [_db executeUpdate:@"CREATE TABLE netstats (_id INTEGER PRIMARY KEY  AUTOINCREMENT  NOT NULL  UNIQUE, wifi INTEGER, wwan INTEGER, overall INTEGER, wifistart_timestamp INTEGER, wifiend_timestamp INTEGER, wifi_totaltime INTEGER, wifi_dirty INTEGER, wwanstart_timestamp INTEGER, wwanend_timestamp INTEGER, wwan_totaltime INTEGER, wwan_dirty INTEGER)"];
@@ -6486,8 +6587,10 @@ CGFloat DistanceBetweenTwoPoints(CGPoint point1,CGPoint point2)
 //    }
     if ([_db tableExists:@"pois"] == NO) {
+        @synchronized (_DatabaseLock) {
         [_db executeUpdate:@"CREATE TABLE pois (id INTEGER PRIMARY KEY NOT NULL UNIQUE, lat NUMERIC, lon NUMERIC, radius NUMERIC)"];
         }
+    }
     [_db makeFunctionNamed:@"DISTANCE" maximumArguments:4 withBlock:^(sqlite3_context *context, int argc, sqlite3_value **argv) {
         distanceFunc(context, argc, argv);
@@ -6498,10 +6601,14 @@ CGFloat DistanceBetweenTwoPoints(CGPoint point1,CGPoint point2)
      * both behaviour and performance.
      * http://sqlite.org/pragma.html
      */
+    @synchronized (_DatabaseLock) {
     [_db executeUpdate:@"PRAGMA auto_vacuum = FULL"];
     WL_FMDBLogError
+    }
+    @synchronized (_DatabaseLock) {
     [_db executeUpdate:@"PRAGMA synchronous = NORMAL"];
     WL_FMDBLogError
+    }
 }
 #pragma mark SQLite functions
@@ -6539,12 +6646,15 @@ static void distanceFunc(sqlite3_context *context, int argc, sqlite3_value **arg
 ///////////////////////////////////////////////////////////////////////////////
 - (BOOL)shouldSendEvents
 {
+    @synchronized (_DatabaseLock) {
     FMResultSet *priorityEvents = [_db executeQuery:@"SELECT COUNT(*) FROM events WHERE priority = 1;"];
     while ([priorityEvents next]) {
         if ([priorityEvents intForColumnIndex:0] > 0) {
             return YES;
         }
     }
+    }
+    @synchronized (_DatabaseLock) {
     FMResultSet *rs = [_db executeQuery:@"SELECT COUNT(*) FROM events;"];
     while ([rs next]) {
@@ -6553,6 +6663,7 @@ static void distanceFunc(sqlite3_context *context, int argc, sqlite3_value **arg
             return YES;
         }
     }
+    }
     return NO;
 }
@@ -6560,6 +6671,7 @@ static void distanceFunc(sqlite3_context *context, int argc, sqlite3_value **arg
 - (NSMutableArray *)topEventDictsInDB
 {
     NSMutableArray *events=[NSMutableArray array];
+    @synchronized (_DatabaseLock) {
     FMResultSet *rs = [_db executeQueryWithFormat:@"SELECT * FROM events ORDER BY _id LIMIT %d", kEventsPerBulk];
     while ([rs next]) {
         NSData *data = [rs dataForColumn:@"data"];
@@ -6568,6 +6680,7 @@ static void distanceFunc(sqlite3_context *context, int argc, sqlite3_value **arg
         [mutableEventDict setObject:[rs objectForColumnName:@"_id"] forKey:@"_id"];
         [events addObject:mutableEventDict];
     }
+    }
     return events;
 }