proxysql/ProxySQL-3.0.4-Release-Notes.md

ProxySQL 3.0.4 Release Notes

This release of ProxySQL 3.0.4 includes significant improvements to PostgreSQL support, MySQL protocol handling, monitoring accuracy, and security.

Release commit: faa64a570d19fe35af43494db0babdee3e3cdc89

New Features:

PostgreSQL Improvements:

• PostgreSQL-Specific Tokenizer for Query Digest Generation (285fb1b4, #5254)
  • Adds PostgreSQL dialect support: dollar-quoted strings ($$...$$), identifier quoting, and dialect-specific comment rules
  • Improved tokenizer for PostgreSQL with nested comments support (f5079037)
  • Adds dedicated handling for double-quoted PostgreSQL identifiers and type cast syntax (value::type) (e70fcbf0)
  • Processes array literals (ARRAY[...] and {...}) and prefixed literals (E'', U&'', x'', b'')
• SSL Support for Backend Connections in PostgreSQL Monitor (7205f424, #5237)
  • PostgreSQL monitor now supports client certificates for SSL/TLS connections to backend servers
  • Adds new metrics PgSQL_Monitor_ssl_connections_OK and PgSQL_Monitor_non_ssl_connections_OK for connection status visibility (fae283cf)

MySQL Protocol Enhancements:

• Special Handling for Unexpected COM_PING Packets (d0e88599, #5257)
  • Implements workaround for unexpected COM_PING packets received during query processing
  • Queues COM_PING packets as counters and sends corresponding OK packets after query completion
  • Improves logging with client address, session status, and data stream status (6fea828e)
• Handling of SELECT @@version and SELECT VERSION() Without Backend (df287b20, #4889)
  • ProxySQL now responds directly to SELECT @@version and SELECT VERSION() queries without backend connection
  • Returns hardcoded server version (currently 8.0.0), reducing unnecessary backend load
• Client-Side wait_timeout Support (abe16e66, #4901)
  • Adds support for client-specified wait_timeout values, previously ignored by ProxySQL
  • Terminates client connections (not backend) when client timeout is reached
  • Clamps client timeout to not exceed global mysql-wait_timeout
• Fast Forward Grace Close Feature to Prevent Data Loss (44aa606c, #5203)
  • Implements graceful connection closure for fast-forward sessions
  • Ensures all pending data is flushed to client before closing connection
  • Prevents data loss during connection termination in replication scenarios

Monitoring & Diagnostics:

• TCP Keepalive Warnings When Disabled (cf454b8e, #5228)
  • Adds warning messages when TCP keepalive is disabled on connections
  • Helps administrators identify potential connection stability issues
  • Includes detailed connection information for troubleshooting

Bug Fixes:

MySQL:

• Make cur_cmd_cmnt Thread-Safe (91e20648, #5259)
  • Fixes thread-safety issue where cur_cmd_cmnt (current command comment) was shared across threads
• Fix cache_empty_result=0 Not Caching Non-Empty Resultsets (2987242d, #5250)
  • Corrects behavior of cache_empty_result field in query rules
  • When set to "0", now correctly caches non-empty resultsets while skipping empty resultsets
  • Previously prevented caching of any resultsets regardless of row count
• Incorrect Affected Rows Reporting for DDL Queries (05960b5d, #5232)
  • Fixes issue #4855 where mysql_affected_rows() in ProxySQL Admin interface incorrectly reported affected rows for DDL queries
  • DDL queries now correctly return 0 affected rows instead of previous DML's count

Monitoring:

• Fix Artificially High Ping Latency in MySQL Backend Monitoring (24e02e95, #5199)
  • Addresses artificially high ping latency measurements
  • Introduces batching for task dispatching (batches of 30) with poll() calls between batches
  • Reduces monitor ping poll() timeout from 100ms to 10ms for more responsive monitoring

Security & Configuration:

• Fix SQL Injection Vulnerability in Read_Global_Variables_from_configfile() (0b2bc1bf, #5247)
  • Replaces sprintf-based SQL query construction with prepared statements using bound parameters
  • Fixes automatic prefix stripping for mysql_variables, pgsql_variables, and admin_variables config parsing (b4683569)
  • Handles cases where users mistakenly include module prefixes (e.g., "mysql-") in variable names

Improvements:

Performance Optimizations:

• Improve Fast Forward Replication CLIENT_DEPRECATE_EOF Validation (5485bb02, #5240)
  • Enhances validation logic for fast forward replication with CLIENT_DEPRECATE_EOF capability flag
  • Ensures proper handling of replication packets and improves compatibility with MySQL 8.0+ clients
• Refactored Prepared-Statement Cache Design (Lock-Free Hot Path) (c0f99c0e, #5225)
  • Implements lock-free hot path for prepared statement cache operations
  • Reduces contention and improves performance for high-concurrency workloads
  • Optimizes transaction command parsing to avoid unnecessary tokenization (e744c2bb)
  • Replaces std::string with char[] to avoid heap allocation in hot paths (7a3a5c71)
• GTID: Refactor Reconnect Logic & Prevent events_count Reset (50c60284, #5226)
  • Refactors GTID reconnect logic to prevent events_count from being reset during reconnection attempts
  • Preserves replication state and reduces unnecessary replication restarts

Documentation:

• Comprehensive Documentation Additions (cf8cbfd8, #5258)
  • Query rules capture groups and backreferences documentation (6966b79d)
  • "Closing killed client connection" warnings documentation (de214cb5)
  • coredump_filters feature documentation addressing issue #5213
  • vacuum_stats() and stats_pgsql_stat_activity Doxygen documentation with bug fix (efe0d4fe)
• Permanent Fast-Forward Sessions and check_data_flow() Documentation (ec1247f2, #5245)
  • Documents behavior of permanent fast-forward sessions
  • Documents MySQL_Data_Stream::check_data_flow() method
  • Explains when bidirectional data checks are skipped for specific session types (4044a407)
• Claude Code Agent Definitions and Architecture Documentation (291e5f02, #5115)
  • Adds architecture documentation for Claude Code agent integration
  • Includes automation framework and internal documentation
• Comprehensive Doxygen Documentation for GTID Refactoring (9a55e974, #5229)
  • Adds detailed Doxygen documentation for GTID-related code changes
• TAP Test Writing Guide and GitHub Automation Improvements (49899601, #5215)
  • Provides comprehensive guide for writing TAP tests for ProxySQL
  • Improves GitHub automation workflows

Testing:

• Add Comments to SELECT @@version Queries to Bypass ProxySQL Interception (66119b74, #5251)
  • Adds /* set_testing */ comments to SELECT @@version queries in test files
  • Prevents ProxySQL interception, allowing queries to reach backend MySQL servers for testing
• Add Fast Forward Replication Deprecate EOF Test and Update Test Infrastructure (9df7407f, #5241)
  • Adds comprehensive test coverage for fast forward replication CLIENT_DEPRECATE_EOF validation
  • Updates test infrastructure to better handle replication scenarios
• Add Delay to Let ProxySQL Process mysql_stmt_close() (fa74de3c, #5198)
  • Adds appropriate delays in tests to allow ProxySQL time to process mysql_stmt_close() operations
  • Prevents race conditions in prepared statement tests
• Regroup Tests to Balance Group Test Time (458ff778, #5207)
  • Reorganizes test groups to balance execution time across test runners
  • Improves CI pipeline efficiency and reduces overall test runtime

Build/Packaging:

• Add OpenSUSE 16 Packaging Support (bce71a95, #5230)
  • Adds packaging support for OpenSUSE 16
  • Expands supported distribution matrix for ProxySQL installations

Other Changes:

• Bump Version to 3.0.4 at Beginning of Development Cycle (ba664785, #5200)
  • Updates version number to 3.0.4 at start of development cycle for clarity and version tracking

Hashes

The release commit is: faa64a570d19fe35af43494db0babdee3e3cdc89