Technologies/PostgreSQL/redis.clients.blocked
PostgreSQLPostgreSQLMetric

redis.clients.blocked

Number of clients pending on a blocking call
Dimensions:None

Summary

Counts the number of clients currently blocked on blocking operations such as BLPOP, BRPOP, or BRPOPLPUSH. A high or growing count indicates many clients waiting synchronously for list operations to complete, which can signal architectural issues with using Redis as a synchronous queue. This metric directly correlates with connection pool exhaustion when many application threads block waiting for data, consuming connection pool capacity without doing useful work.

Related Insights (2)
Slow Query Backlog Masks Redis Connection Pool Exhaustionwarning

Redis slowlog entries accumulating (redis.slowlog.length rising) can indicate operations blocking on network or disk I/O, exhausting connection pools and causing cascading failures in dependent services even when Redis CPU appears healthy.

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Blocked Clients Indicate Synchronous Operation Bottleneckwarning

Increasing redis.clients.blocked count indicates clients waiting on blocking operations (BLPOP, BRPOP, BRPOPLPUSH, BLMOVE, BZPOPMIN, BZPOPMAX), which can cause connection pool exhaustion if client timeouts are too long or if producers aren't keeping up with consumers.

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