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TiFlash Alert Rules

This document introduces the alert rules of the TiFlash cluster.

TiFlash_schema_error

  • Alert rule:

    increase(tiflash_schema_apply_count{type="failed"}[15m]) > 0

  • Description:

    When the schema apply error occurs, an alert is triggered.

  • Solution:

    The error might be caused by some wrong logic. Contact TiFlash R&D for support.

TiFlash_schema_apply_duration

  • Alert rule:

    histogram_quantile(0.99, sum(rate(tiflash_schema_apply_duration_seconds_bucket[1m])) BY (le, instance)) > 20

  • Description:

    When the probability that the apply duration exceeds 20 seconds is over 99%, an alert is triggered.

  • Solution:

    It might be caused by the internal problems of the TiFlash TMT engine. Contact TiFlash R&D for support.

TiFlash_raft_read_index_duration

  • Alert rule:

    histogram_quantile(0.99, sum(rate(tiflash_raft_read_index_duration_seconds_bucket[1m])) BY (le, instance)) > 3

  • Description:

    When the probability that the read index duration exceeds 3 seconds is over 99%, an alert is triggered.

    Note:

    read index is the kvproto request sent to the TiKV leader. TiKV region retries, busy store, or network problems might lead to long request time of read index.

  • Solution:

    The frequent retries might be caused by frequent splitting or migration of the TiKV cluster. You can check the TiKV cluster status to identify the retry reason.

TiFlash_raft_wait_index_duration

  • Alert rule:

    histogram_quantile(0.99, sum(rate(tiflash_raft_wait_index_duration_seconds_bucket[1m])) BY (le, instance)) > 2

  • Description:

    When the probability that the waiting time for Region Raft Index in TiFlash exceeds 2 seconds is over 99%, an alert is triggered.

  • Solution:

    It might be caused by a communication error between TiKV and the proxy. Contact TiFlash R&D for support.