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TiCDC Alert Rules

This document describes the TiCDC alert rules and the corresponding solutions. In descending order, the severity levels are: Critical, Warning.

Critical alerts

This section introduces critical alerts and solutions.

cdc_checkpoint_high_delay

For critical alerts, you need to pay close attention to abnormal monitoring metrics.

cdc_resolvedts_high_delay

  • Alert rule:

    (time() - ticdc_processor_resolved_ts / 1000) > 300

  • Description:

    The Resolved TS of a replication task is delayed more than 10 minutes.

  • Solution:

    See TiCDC Handle Replication Interruption.

ticdc_processor_exit_with_error_count

Warning alerts

Warning alerts are a reminder for an issue or error.

cdc_multiple_owners

  • Alert rule:

    sum(rate(ticdc_owner_ownership_counter[30s])) >= 2

  • Description:

    There are multiple owners in the TiCDC cluster.

  • Solution:

    Collect TiCDC logs to locate the root cause.

ticdc_mounter_unmarshal_and_mount_time_more_than_1s

  • Alert rule:

histogram_quantile(0.9, rate(ticdc_mounter_unmarshal_and_mount_bucket[1m])) * 1000 > 1000

  • Description:

    It takes a replication task more than 1 second to unmarshal the data changes.

  • Solution:

    Collect TiCDC logs to locate the root cause.

cdc_sink_execute_duration_time_more_than_10s

  • Alert rule:

    histogram_quantile(0.9, rate(ticdc_sink_txn_exec_duration_bucket[1m])) > 10

  • Description:

    It takes a replication task more than 10 seconds to write data to the downstream database.

  • Solution:

    Check whether there are problems in the downstream database.

cdc_processor_checkpoint_tso_no_change_for_1m

ticdc_puller_entry_sorter_sort_bucket

  • Alert rule:

    histogram_quantile(0.9, rate(ticdc_puller_entry_sorter_sort_bucket{}[1m])) > 1

  • Description:

    The delay of TiCDC puller entry sorter is too high.

  • Solution:

    Collect TiCDC logs to locate the root cause.

ticdc_puller_entry_sorter_merge_bucket

  • Alert rule:

    histogram_quantile(0.9, rate(ticdc_puller_entry_sorter_merge_bucket{}[1m])) > 1

  • Description:

    The delay of TiCDC puller entry sorter merge is too high.

  • Solution:

    Collect TiCDC logs to locate the root cause.

tikv_cdc_min_resolved_ts_no_change_for_1m

  • Alert rule:

    changes(tikv_cdc_min_resolved_ts[1m]) < 1 and ON (instance) tikv_cdc_region_resolve_status{status="resolved"} > 0

  • Description:

    The minimum Resolved TS 1 of TiKV CDC has not advanced for 1 minute.

  • Solution:

    Collect TiKV logs to locate the root cause.

tikv_cdc_scan_duration_seconds_more_than_10min

  • Alert rule:

    histogram_quantile(0.9, rate(tikv_cdc_scan_duration_seconds_bucket{}[1m])) > 600

  • Description:

    The TiKV CDC module has scanned for incremental replication for more than 10 minutes.

  • Solution:

    Collect TiCDC monitoring metrics and TiKV logs to locate the root cause.

ticdc_sink_mysql_execution_error

  • Alert rule:

    changes(ticdc_sink_mysql_execution_error[1m]) > 0

  • Description:

    An error occurs when a replication task writes data to the downstream MySQL.

  • Solution:

    There are many possible root causes. See Troubleshoot TiCDC.

ticdc_memory_abnormal

  • Alert rule:

    go_memstats_heap_alloc_bytes{job="ticdc"} > 1e+10

  • Description:

    The TiCDC heap memory usage exceeds 10 GiB.

  • Solution:

    Collect TiCDC logs to locate the root cause.