Document metrics that help detect when WAL apply lag is increasing #191
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🚀 Build success! Latest successful preview: https://preview-191--questdb-documentation.netlify.app/docs/ Commit SHA: 0644a51
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mtopolnik
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Adds three new metrics to the table of all metrics:
questdb_wal_apply_seq_txn_totalquestdb_wal_apply_writer_txn_totalquestdb_suspended_tablesTODO: document how to use these metrics:
To track increasing WAL apply lag not caused by suspended tables, monitor the difference
questdb_wal_apply_seq_txn_total - questdb_wal_apply_writer_txn_total. If it's persistently growing, it is likely that at least one table is falling seriously behind.The gauge
questdb_suspended_tablesis simpler, any value above zero is a sign of trouble.