The server returns an OK packet whose size exceeds the client’s max_allowed_packet threshold, breaking the connection.
MySQL error 3068 (ER_NET_OK_PACKET_TOO_LARGE) occurs when the server sends an OK packet larger than the client’s max_allowed_packet limit, forcing the connection to close. Raise max_allowed_packet on both client and server, or reduce the result size, to resolve the issue.
ER_NET_OK_PACKET_TOO_LARGE
Error 3068 appears when a MySQL client receives an OK packet whose byte size exceeds the client-side max_allowed_packet setting. The server attempts to confirm a statement or handshake, but the oversized packet breaches the network protocol limits, so the client treats it as a fatal network error and closes the connection.
The condition name ER_NET_OK_PACKET_TOO_LARGE was introduced in MySQL 5.7.5. The SQL state 08S01 classifies it as a communication error. Applications may see lost connections, interrupted transactions, or incomplete result sets if the problem is not handled quickly.
MySQL uses OK packets to acknowledge successful queries, prepared statement commands, and authentication. An OK packet normally carries minimal metadata, but features like session state tracking or multi-statement responses can enlarge it. When the packet crosses the size limit, the protocol is violated, risking data loss and instability.
Mismatch between client max_allowed_packet and server-generated packet size is the primary cause. Large session state information, many warnings, or large generated columns can bloat the packet.
Upgrading MySQL without aligning client libraries can introduce stricter defaults, making previously safe operations fail with error 3068.
Raise max_allowed_packet on both server and client to a value larger than the observed packet. Restart the client or reconnect to apply the change.
If increasing the limit is not possible, reduce packet size by disabling session_track_* variables or limiting warnings.
Bulk INSERT … ON DUPLICATE KEY UPDATE returning many warnings can create an oversized OK packet. Suppress warnings with INSERT IGNORE or handle duplicates beforehand.
Replication clients with small packet limits may fail during row-based replication. Configure slave_net_timeout and match max_allowed_packet across replication channels.
Standardize max_allowed_packet in configuration management for every client and server host. Monitor packet statistics with performance_schema status variables.
During upgrades, verify default sizes and run integration tests with realistic data volumes to catch packet growth early.
ER_NET_PACKET_TOO_LARGE (1153) signals an oversized result set packet. ER_NET_READ_ERROR_FROM_PIPE (3011) indicates broken pipes during packet read. Both are resolved by aligning packet limits and ensuring stable network links.
The application or connector uses a default packet size (1 MB in many libraries) while the server sends a larger OK packet, resulting in immediate disconnect.
Variables such as session_track_schema and session_track_system_variables can enlarge the OK packet when many variables change per statement.
Bulk operations that trigger thousands of warnings attach this metadata to the OK packet, pushing it over the limit.
A new server with additional OK-packet fields talks to an old client library that retains a small default packet size.
Triggered when a result set row packet exceeds max_allowed_packet. Fix by raising the same variable or using streaming.
Indicates read failure on Windows named pipes during packet transfer. Resolve by inspecting OS network stack.
Occurs when the server cannot write a packet to the client. Often linked to firewall timeouts or socket exhaustion.
Increasing it only allocates more memory when needed, so normal workloads remain unaffected. Keep the value reasonable to prevent memory abuse.
No. It specifically targets the OK packet after a statement, not the rows returned. For large result rows, error 1153 applies.
MySQL 8.0 adds more session tracking fields, making OK packets larger. Align client library versions or raise packet limits.
Galaxy’s editor surfaces server parameters and warns when max_allowed_packet is low. Integrated scripts let you adjust settings fast and share the fix with teammates.
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