MySQL-CDC diagnostic: cannot compare binlog sequence because

Error message

MySQL-CDC diagnostic: cannot compare binlog sequence because available binlog filenames don't match required prefix '{}'

What it means

Part of the binlog-not-available diagnostics: the connector parsed available binlog filenames from SHOW BINARY LOGS, but none of them matched the prefix of the required binlog file (e.g. required 'mysql-bin.000123' while server files are named 'binlog.000001'). Without a shared prefix, sequence comparison is impossible, so the connector reports it cannot determine whether the required file is older/newer than what the server has.

Source

Thrown at seatunnel-connectors-v2/connector-cdc/connector-cdc-mysql/src/main/java/org/apache/seatunnel/connectors/seatunnel/cdc/mysql/source/reader/fetch/MySqlSourceFetchTaskContext.java:621

        BinlogFileNumber required = parseBinlogFileNumber(requiredBinlogFilename);
        if (required == null) {
            return;
        }

        long min = Long.MAX_VALUE;
        long max = Long.MIN_VALUE;
        boolean any = false;
        for (String file : availableBinlogFiles) {
            BinlogFileNumber parsed = parseBinlogFileNumber(file);
            if (parsed == null || !required.prefix.equals(parsed.prefix)) {
                continue;
            }
            any = true;
            min = Math.min(min, parsed.number);
            max = Math.max(max, parsed.number);
        }
        if (!any) {
            LOG.warn(
                    "MySQL-CDC diagnostic: cannot compare binlog sequence because available binlog filenames don't match required prefix '{}'",
                    required.prefix);
            return;
        }

        if (required.number < min) {
            LOG.warn(
                    "MySQL-CDC diagnostic: required binlog sequence {}{} is older than the earliest available {}{}; likely purged/expired binlog on server",
                    required.prefix,
                    required.number,
                    required.prefix,
                    min);
        } else if (required.number > max) {
            LOG.warn(
                    "MySQL-CDC diagnostic: required binlog sequence {}{} is newer than the latest available {}{}; possible connection to an out-of-date replica, proxy routing to different instance, or RESET MASTER",
                    required.prefix,
                    required.number,
                    required.prefix,

View on GitHub (pinned to cf67b549a7)

Solutions

Verify the job is connecting to the same MySQL instance that produced the required offset (check host, port, and proxy/replica routing).
Check the server's log_bin_basename in my.cnf — if the prefix changed, the required offsets are no longer interpretable; restart the CDC job from snapshot or a valid position.
Compare output of SHOW BINARY LOGS against the required filename manually.
If a proxy/load balancer is in front of MySQL, pin the connection to a single node.

Example fix

// before: my.cnf prefix changed
log-bin = new-bin
// after: keep the original basename so old offsets remain valid
log-bin = mysql-bin

Defensive patterns

Strategy: validation

Validate before calling

SHOW BINARY LOGS; -- verify filename prefixes match the offset's binlog file, e.g. mysql-bin.%d

Prevention

Never change log-bin basename on a server with live CDC consumers.
Pin CDC connections to a single instance (avoid LB/replica flapping).
Record the server's log_bin_basename when creating jobs.
Watch for RESET MASTER events in ops procedures.

When it happens

Trigger: logBinlogRangeAnalysis is invoked from logBinlogNotAvailableDiagnostics after a required binlog file is missing; every available filename fails to parse against required.prefix (log-bin basename changed, or server is a different instance with different naming).

Common situations: log-bin basename renamed in my.cnf and server restarted; connecting to a replica/proxy with different binlog naming than the original master; RESET MASTER wiping and regenerating files with a new prefix; switching between MySQL and MariaDB (mysql-bin vs mariadb-bin).

Understand the failure class

Background: "invalid id" errors: invalid identifier format — why libraries reject IDs before lookup, and how to fix them — this error's family across 37 libraries.

Related errors

AI-assisted analysis of apache/seatunnel@cf67b549a7 (2026-09-10). Data as JSON: /api/errors/b91bdbecc2fd3f92. Report an issue: GitHub.