{"record":{"id":"7c33c264b37f3e71","repo":"alibaba/canal","slug":"can-t-find-start-position-for","errorCode":null,"errorMessage":"can't find start position for {}","messagePattern":"can't find start position for (.+?)","errorType":"exception","errorClass":"PositionNotFoundException","httpStatus":null,"severity":"error","filePath":"parse/src/main/java/com/alibaba/otter/canal/parse/inbound/AbstractEventParser.java","lineNumber":189,"sourceCode":"                        preDump(erosaConnection);\r\n\r\n                        erosaConnection.connect();// 链接\r\n\r\n                        long queryServerId = erosaConnection.queryServerId();\r\n                        if (queryServerId != 0) {\r\n                            serverId = queryServerId;\r\n                        }\r\n\r\n                        if (erosaConnection instanceof MysqlConnection) {\r\n                            isMariaDB = ((MysqlConnection) erosaConnection).isMariaDB();\r\n                        }\r\n                        // 4. 获取最后的位置信息\r\n                        long start = System.currentTimeMillis();\r\n                        logger.warn(\"---> begin to find start position, it will be long time for reset or first position\");\r\n                        EntryPosition position = findStartPosition(erosaConnection);\r\n                        final EntryPosition startPosition = position;\r\n                        if (startPosition == null) {\r\n                            throw new PositionNotFoundException(\"can't find start position for \" + destination);\r\n                        }\r\n\r\n                        if (!processTableMeta(startPosition)) {\r\n                            throw new CanalParseException(\"can't find init table meta for \" + destination\r\n                                                          + \" with position : \" + startPosition);\r\n                        }\r\n                        long end = System.currentTimeMillis();\r\n                        logger.warn(\"---> find start position successfully, {}\", startPosition.toString() + \" cost : \"\r\n                                                                                 + (end - start)\r\n                                                                                 + \"ms , the next step is binlog dump\");\r\n                        // 重新链接，因为在找position过程中可能有状态，需要断开后重建\r\n                        erosaConnection.reconnect();\r\n\r\n                        final SinkFunction sinkHandler = new SinkFunction<EVENT>() {\r\n\r\n                            private LogPosition lastPosition;\r\n\r\n                            public boolean sink(EVENT event) {\r","sourceCodeStart":171,"sourceCodeEnd":207,"githubUrl":"https://github.com/alibaba/canal/blob/87be50e87686a3e8af08c368d0e1ffd1f59eb04a/parse/src/main/java/com/alibaba/otter/canal/parse/inbound/AbstractEventParser.java#L171-L207","documentation":"Thrown as PositionNotFoundException when AbstractEventParser cannot determine a binlog start position after calling findStartPosition(erosaConnection). Without a start position the parser cannot begin a binlog dump, so startup aborts. It is the most common 'fresh start with no position' failure.","triggerScenarios":"In the parse thread, after connecting and (for MySQL) reading serverId/isMariaDB, findStartPosition returns null. This occurs on first start with no persisted position, after a position reset, when the binlog does not contain a matching GTID/position, or when the configured start criteria (timestamp/journal/gtid) yield nothing.","commonSituations":"First launch of an instance with no cursor saved; binlogs on the MySQL master have been purged/rotated past the requested start; GTID mode but the requested GTID set is not present; timestamp-based start older than retained binlogs; MySQL user lacks REPLICATION SLAVE/REPLICATION CLIENT privileges so SHOW MASTER STATUS returns nothing.","solutions":["Confirm the MySQL user has REPLICATION SLAVE and REPLICATION CLIENT privileges (and SELECT on needed tables).","If first start, set canal.instance.master.address correctly and ensure binlogs exist; let Canal record the current master position.","If resuming, verify the persisted zk/file position still references an existing binlog file (not purged).","For GTID mode, ensure the requested GTID is present on the master and gtid mode is enabled on the source."],"exampleFix":"-- grant the canal MySQL user the required rights\nGRANT SELECT, REPLICATION SLAVE, REPLICATION CLIENT ON *.* TO 'canal'@'%';","handlingStrategy":"validation","validationCode":"-- ensure the canal user can report a start position\nSHOW GRANTS FOR 'canal'@'%';\n-- must include REPLICATION SLAVE, REPLICATION CLIENT, SELECT\nSHOW MASTER STATUS; -- non-empty => a start position exists","typeGuard":null,"tryCatchPattern":"try { parser.start(); }\ncatch (PositionNotFoundException e) {\n    // first start or binlogs purged; seed from current master position then retry\n    seedPositionFromMaster(); parser.start();\n}","preventionTips":["Grant REPLICATION SLAVE/CLIENT to the canal MySQL user.","Persist positions (zk/file) so restarts resume rather than re-find.","Ensure requested binlogs/GTIDs still exist on the source."],"tags":["parse","binlog","position","startup","permissions"],"backgroundTag":null,"analyzedSha":"87be50e87686a3e8af08c368d0e1ffd1f59eb04a","analyzedAt":"2026-08-14T04:30:11.918Z","schemaVersion":2},"datasetVersion":"2026-08-14T05:17:29.042Z"}