Current documented limits
| Constraint | Current value | Scope | Verified source |
|---|---|---|---|
| simultaneous client connectionsThe effective maximum is also constrained by open_files_limit. | 151 default; configurable 1–100,000 | MySQL 8.4 server | OracleAug 22, 2026 |
| internal row representationBLOB and TEXT contents are stored separately, but their pointers and overhead still count. | 65,535 bytes | MySQL 8.4 | OracleAug 22, 2026 |
| columns per tableEffective counts can be lower because row size and hidden generated columns also apply. | 4,096 hard limit; InnoDB limit 1,017 | MySQL 8.4 | OracleAug 22, 2026 |
| network write timeoutnet_write_timeout can be configured from 1 second to one year. | 60 seconds default | MySQL 8.4 | OracleAug 22, 2026 |
How to apply MySQL limits safely
The monitored baseline covers simultaneous client connections, internal row representation, columns per table, network write timeout. Treat these as separate constraints rather than one platform-wide capacity number: a workload can fit one row and still fail another because the plan, model, endpoint, runtime, region, invocation mode, or account scope differs.
- Match the production workload to the exact scope printed beside each value and confirm it in the active MySQL console, configuration, or response headers.
- Measure the serialized request, token volume, duration, concurrency, storage, or connection demand at realistic percentiles, then preserve headroom for bursts and retries.
- Check every adjacent layer—client, SDK, gateway, proxy, queue, database, and downstream service—for a smaller effective limit before changing architecture.
Specific limit pages
These pages exist because the constraint has a distinct implementation or troubleshooting intent. Closely related keyword variations stay consolidated.
MySQL max_connections Limit
MySQL max_connections Limit, verified against MySQL's official documentation with scope, implementation impact, caveats, and a direct check.
MySQL Row Size Limit
MySQL Row Size Limit, verified against MySQL's official documentation with scope, implementation impact, caveats, and a direct check.
MySQL Column Count Limit
MySQL Column Count Limit, verified against MySQL's official documentation with scope, implementation impact, caveats, and a direct check.
MySQL Network Timeout Defaults
MySQL Network Timeout Defaults, verified against MySQL's official documentation with scope, implementation impact, caveats, and a direct check.
Errors linked to these limits
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Redis vs MySQL Connection Limits using the same verified structured observations as each underlying limit page, with scope and comparability caveats.