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Tool for DBAs

MySQL and MariaDB memory calculator

Model global buffers, per-connection costs, and temporary tables for every MySQL and MariaDB generation before changing production configuration.

1. Enter your configuration

All sizes are in MiB.

2. Compare with RAM

The planning budget uses 70% of RAM.

3. Validate under load

This is a model; verify with production metrics.

Server family and version

The preset changes the temporary-table model, engine-specific caches, and recommendations.

Server capacity and connections

max_connections is not reserved memory, but it defines the possible worst case.

MiB

Global memory

Allocated once per MySQL process, before accounting for connection work.

Per-connection buffers

These are allocated on demand. The ceiling uses max_connections to expose the configuration risk.

How to interpret it

The base peak adds global buffers and every per-connection buffer. It does not mean MySQL allocates it all at startup; it shows the commitment the configuration can make under concurrency.

Temporary tables

On MySQL 8+, tmp_table_size limits each internal temporary table and temptable_max_ram controls global TempTable use. Do not blindly multiply tmp_table_size without checking those limits and query behavior.

Before applying

Confirm effective values with SHOW VARIABLES, observe real connection concurrency, and validate host memory use. Tuning should reduce measurable risk, not just increase buffers.

From calculation to real operations

A calculator shows the risk. PG Monitoring shows when it is happening.

This calculator is an estimate for MySQL and MariaDB. PG Monitoring specializes in PostgreSQL and applies the same capacity discipline with real telemetry, not static assumptions.

Assisted diagnostic: we never request passwords or connection strings through forms, email, or WhatsApp.

What the SaaS tracks in PostgreSQL

  • Memory, connections, waits, I/O, and real-time health
  • Slow queries, plans, temporary files, and regressions
  • Autovacuum, bloat, locks, replication, and operational risk
  • Configuration recommendations with workload context
  • Alerts and history to prove whether a change improved things

Frequently asked questions

How much RAM can MySQL or MariaDB use?+

Use RAM effectively available to the process, not all physical host memory. This calculator reserves 30% for the operating system, page cache, and unmodeled spikes.

Does max_connections reserve memory immediately?+

No. The limit does not allocate everything at startup, but it defines how many connections can request per-connection buffers concurrently and therefore the capacity worst case.

How do MySQL 8 and MariaDB temporary tables differ?+

Modern MySQL uses TempTable with a global budget such as temptable_max_ram. MariaDB uses per-connection temporary-table limits such as tmp_memory_table_size and max_heap_table_size.

Does query_cache_size work in MySQL 8?+

No. Query Cache was removed in MySQL 8. It still exists in MariaDB, but should be evaluated carefully because of lock contention.

Technical references: MySQL documentation on memory use and TempTable, and MariaDB documentation on memory allocation. This tool is a planning model, not a replacement for load testing or process observability.

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