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MySQL

Monitor MySQL queries, connections, replication, users, InnoDB, storage, and resource performance metrics.

Guides

Guides overview 1 page

MySQL Operations Guides

Practical guides for running, troubleshooting, and monitoring MySQL in production.

MySQL Operations Guides 32 pages

Open the MySQL Operations Guides hub

MySQL Aborted Connections: Causes And Fixes

Diagnose rising MySQL Aborted_connects and Aborted_clients counters. Distinguish handshake failures from dropped connections, find the root cause, and fix it without restarting the server.

MySQL Binary Log Disk Full: How To Fix It

Diagnose and fix MySQL binary log disk exhaustion caused by missing expiry, lagging replicas, or oversized transactions. Safe manual purge procedures and prevention.

MySQL connection exhaustion: detection, diagnosis, and prevention

Detect, diagnose, and prevent MySQL connection exhaustion before application errors cascade into an outage.

MySQL ERROR 1040 (HY000): Too many connections - causes and fixes

Troubleshoot MySQL ERROR 1040 (HY000) by distinguishing connection leaks from genuine overload, using Threads_running, Threads_connected, and Connection_errors_max_connections.

MySQL ERROR 1045 (28000): Access denied for user - diagnosis

Diagnose MySQL ERROR 1045 (28000) caused by credential mismatches, user@host restrictions, authentication plugin incompatibility, and host cache blocking.

MySQL ERROR 1205: Lock wait timeout exceeded; try restarting transaction

Diagnose and fix MySQL ER_LOCK_WAIT_TIMEOUT. Find blocking transactions, understand statement-level rollback, and prevent row lock contention in production.

MySQL ERROR 1213: Deadlock found when trying to get lock; try restarting transaction

Diagnose and resolve MySQL ERROR 1213 deadlocks in InnoDB. Covers victim selection, gap-lock interaction, diagnostic commands, and prevention.

MySQL ERROR 2006/2013: MySQL server has gone away -- causes and fixes

Troubleshoot MySQL ERROR 2006 and 2013 by distinguishing idle timeout closures from crashes, packet limits, and network timeouts.

MySQL FLUSH TABLES WITH READ LOCK stall: backups that freeze the server

Diagnose and prevent whole-server freezes caused by FLUSH TABLES WITH READ LOCK during MySQL backups.

MySQL full table scans: Handler_read_rnd_next and the missing index

Diagnose unexpected full table scans in MySQL by correlating Handler_read_rnd_next step-changes with Slow_queries, then isolate the offending query and fix the index coverage.

MySQL Got error 28 from storage engine / No space left on device — recovery

Recover from MySQL errno 28 disk-full conditions by identifying whether binlogs, redo logs, tmpdir, or relay logs consumed the space, and apply the right fix without causing data loss.

MySQL GTID errant transactions: detecting replication divergence

Detect true GTID replication divergence versus ordinary lag, identify errant transactions, and decide between empty-transaction injection or a full rebuild.

MySQL InnoDB buffer pool hit ratio collapse: the cliff edge

Diagnose and fix InnoDB buffer pool hit ratio collapse when the working set exceeds memory, causing non-linear query degradation and cascading connection pressure.

MySQL InnoDB checkpoint age: the redo log capacity signal nobody watches

How to monitor InnoDB checkpoint age in MySQL 8.0+, understand the redo log capacity cliff edge, and avoid the write stalls that take production down.

MySQL InnoDB history list length growing: purge lag explained

Understand how InnoDB purge lag works, why the history list length grows, and how MVCC read views turn a single idle transaction into fleet-wide slowdown.

MySQL InnoDB redo log checkpoint stall: when all writes freeze

Diagnose and fix InnoDB redo log checkpoint stalls that synchronously freeze all MySQL writes when checkpoint age exceeds redo capacity.

MySQL InnoDB row lock contention: finding who blocks whom

Diagnose InnoDB row lock contention in MySQL 8.0+ and 5.7 by mapping blocking transactions with performance_schema.data_lock_waits, sys.innodb_lock_waits, and the right status metrics.

MySQL innodb_buffer_pool_size tuning: 60-80% of RAM and when that breaks

Operational guide to sizing MySQL's InnoDB buffer pool, the 60-80% RAM heuristic, alignment constraints, and the container and memory gotchas that make it fail.

MySQL Innodb_buffer_pool_wait_free > 0: buffer pool memory pressure

Diagnose and fix InnoDB buffer pool memory pressure when Innodb_buffer_pool_wait_free climbs above zero.

MySQL innodb_redo_log_capacity sizing: how big should the redo log be

Size the MySQL InnoDB redo log to avoid checkpoint stalls. Covers 8.0.30+ dynamic capacity, headroom calculations, and flush tuning.

MySQL long-running transactions: detecting and killing the silent blocker

Detect, diagnose, and kill idle InnoDB transactions that silently hold locks and block purge, causing lock waits and history list growth.

MySQL metadata lock cascade: how one ALTER TABLE freezes a whole table

Diagnose and break a metadata lock cascade when DDL blocks behind a long transaction and connection pools fill with waiting DML.

MySQL monitoring checklist: the signals every production instance needs

A tiered operational reference of the core MySQL signals every production instance needs, from survival metrics to expert-level lock diagnostics.

MySQL online DDL still blocking: ALGORITHM, LOCK, and the copy phase

Why MySQL online DDL still blocks despite ALGORITHM=INPLACE/INSTANT and LOCK=NONE, and how metadata locks cause copy-phase stalls.

MySQL OOM-killed: buffer pool, per-connection buffers, and the kernel killer

Diagnose and prevent Linux OOM killer evictions of MySQL by understanding buffer pool sizing, per-connection memory, and kernel interactions.

MySQL purge lag from an idle transaction: the slow bleed

Diagnose and fix InnoDB purge lag caused by a single idle transaction holding an MVCC read view, leading to unbounded history list growth and gradual query degradation.

MySQL query plan regression: when a query gets slow after a deploy or ANALYZE

Diagnose and fix sudden MySQL query slowdowns caused by bad execution plans after deployments, ANALYZE TABLE, schema changes, or upgrades.

MySQL Replica_IO_Running / Replica_SQL_Running not Yes: replication stopped

Diagnose why MySQL replication I/O or SQL threads stop, read SHOW REPLICA STATUS errors, and recover safely.

MySQL replication lag spiral: Seconds_Behind_Source growing without bound

Diagnose and stop a MySQL replication lag death spiral when the replica cannot keep up, relay logs grow, and Seconds_Behind_Source increases monotonically.

MySQL slow commits with idle CPU: redo and binlog fsync pressure

Diagnose and fix MySQL commit latency when CPU is idle but transactions stall on redo log and binary log fsync pressure.

MySQL slow queries: from Slow_queries to the slow log to the fix

Diagnose MySQL slow queries when Slow_queries climbs, the slow log is disabled, or long_query_time hides real problems. Read-only checks, ratio analysis, and targeted fixes.

MySQL Waiting for table metadata lock: diagnosing the DDL stall

Diagnose MySQL sessions stuck in Waiting for table metadata lock, identify the blocking transaction, and break the DDL stall before connection exhaustion.

Academy

Whats The Difference Between PostgreSQL vs MySQL

A deep dive into the features- performance- and use cases of two leading open-source relational databases

MySQL Monitoring

Learn everything about monitoring & troubleshooting MySQL, what metrics are important to monitor and why, and how to monitor MySQL with Netdata.

ProxySQL Monitoring

Learn everything about monitoring & troubleshooting ProxySQL, what metrics are important to monitor and why, and how to monitor ProxySQL with Netdata.

Case Studies

InRento Case Study: Fintech Cloud Monitoring Wins

Overcoming Cloud Migration Challenges and Enhancing Operational Resilience

Codyas: Global Server Management with Netdata

Achieving Efficiency and Security Across Diverse Infrastructures

Resources

Best MySQL Monitoring Tools: 10 Options Ranked for 2026

We rank the 10 best MySQL monitoring tools for 2026, comparing query analytics, replication visibility, deployment flexibility, and total cost of ownership.

Best ProxySQL Monitoring Tools: 6 Ranked for 2026

The 6 best ProxySQL monitoring tools ranked by connection pool depth, collection resolution, backend health alerting, and cost shape, from Netdata to Zabbix.

Webinar: Live Database & Network Diagnostics

See how Netdata's new Live Functions let you analyze slow queries, detect deadlocks, and monitor SNMP network interfaces directly from the Netdata dashboard, with a live demo.

Blog

Database Performance Monitoring: 14+ DBs Supported

Slow queries, running operations, deadlocks, and errors for PostgreSQL, MySQL, MongoDB, SQL Server, Oracle, and more.

Monitor any SQL metrics with Netdata (and Pandas ❤️)

Integrating Python and SQL for Advanced Data Analysis