MySQL Memory Usage by Component

Shows the biggest memory consumers and total allocated memory. Used when investigating OOM kills and suspected memory leaks.

#memory#performance_schema#sys-schema

mysql · sql

SELECT event_name, current_count, current_alloc, high_alloc
FROM sys.memory_global_by_current_bytes
LIMIT 15;

SELECT * FROM sys.memory_global_total;

Operational Notes & Remediation Guidance

Innodb_buffer_pool_size typically accounts for 60-80% of total system memory on dedicated database hosts.

Production Safety & Execution Standards

This script is designed for read-only diagnostics; it does not alter schema or modify data directly.
Prior to executing on production systems under high load, verify the target database version (Min. Version: 5.7).
Exercise caution with mutating actions (e.g., terminating sessions or dropping indexes) referenced in the notes section.

Engineering Triad: Related Runbooks & Incident Response

Which production incidents and emergency drills execute this script as a diagnosis step?

Distinguishes cache warm-up, large scans and insufficient RAM behind a lower hit ratio; evaluates queries and memory settings safely.

Related Alerts & Metrics

M16MySQL InnoDB Buffer Pool Hit RatioMySQL

Lists active queries running longer than 60 seconds from the processlist. Fast diagnosis for slowdowns and lock pile-ups.

Uses the sys schema to show waiting and blocking sessions with lock modes. Resolves who is holding up whom in a single query.

Ranks tables by data, index and free space size. Core input for capacity planning and archiving decisions.

Uses sys.schema_unused_indexes to list indexes that were never used. Helps safely drop indexes that slow down writes.