# Related metrics

> Signals used to decide whether a wait is expected or harmful.
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Signals used to decide whether a wait is expected or harmful. This index contains **22** entries.

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Section pages:

- [[[metric:active_backends]]](/metric/active-backends/): Backends currently executing a query.
- [[[metric:blocked_sessions]]](/metric/blocked-sessions/): Sessions with one or more blocking PIDs.
- [[[metric:blocks_read]]](/metric/blocks-read/): Relation blocks read by database or statement.
- [[[metric:buffer_hit_ratio]]](/metric/buffer-hit-ratio/): Blocks served from shared buffers versus blocks read.
- [[[metric:checkpoint_time]]](/metric/checkpoint-time/): Checkpoint write and synchronization duration.
- [[[metric:commit_latency]]](/metric/commit-latency/): End-to-end transaction commit latency.
- [[[metric:io_read_time]]](/metric/io-read-time/): Timed read latency from pg_stat_io or operating-system telemetry.
- [[[metric:io_write_time]]](/metric/io-write-time/): Timed write latency from pg_stat_io or operating-system telemetry.
- [[[metric:locks_per_backend]]](/metric/locks-per-backend/): Rows in pg_locks grouped by backend.
- [[[metric:multixact_member_io]]](/metric/multixact-member-io/): Reads and writes for multixact member storage.
- [[[metric:oldest_multixact_age]]](/metric/oldest-multixact-age/): Oldest multixact age that still requires preservation.
- [[[metric:oldest_transaction_age]]](/metric/oldest-transaction-age/): Age of the oldest open transaction or visibility horizon.
- [[[metric:replication_flush_lag]]](/metric/replication-flush-lag/): Distance or time between primary WAL and standby flush position.
- [[[metric:statement_latency]]](/metric/statement-latency/): Latency distribution for statements associated with the wait.
- [[[metric:statement_wal_bytes]]](/metric/statement-wal-bytes/): WAL bytes attributed to statements when pg_stat_statements tracks WAL.
- [[[metric:wait_event_share]]](/metric/wait-event-share/): Share of repeated active-session samples attributed to one event.
- [[[metric:waiting_sessions]]](/metric/waiting-sessions/): Current sessions grouped by wait type and event.
- [[[metric:wal_bytes]]](/metric/wal-bytes/): WAL bytes generated over the observation interval.
- [[[metric:wal_fpi]]](/metric/wal-fpi/): Full-page images generated in WAL.
- [[[metric:wal_sync_time]]](/metric/wal-sync-time/): Time spent synchronizing WAL to durable storage.
- [[[metric:wal_write_time]]](/metric/wal-write-time/): Time spent writing WAL.
- [[[metric:xact_slru_io]]](/metric/xact-slru-io/): Reads and writes for the transaction-status SLRU.