feat: Implement NoWait mechanism for database distributed lock

[wushiyuanmaimob]

Summary

This PR implements the NoWait mechanism for database distributed locks to address issue #7993, resolving the TODO comment at line 150 in DataBaseDistributedLocker.

Problem: Under high concurrency (500+ TPS), the current SELECT ... FOR UPDATE blocks threads for 100-500ms when lock contention occurs, waiting for database lock timeout.

Solution: Introduce FOR UPDATE NOWAIT support for MySQL 8.0+, PostgreSQL, and Oracle, reducing lock contention latency to <1ms by failing fast instead of blocking.

Changes

• SQL Dialect Support: Added MysqlDistributedLockSql, PostgresqlDistributedLockSql, and OracleDistributedLockSql with NOWAIT support
• Interface Extension: Added getSelectDistributeForUpdateNoWaitSql() to DistributedLockSql interface with default fallback
• Configuration Switch: Added store.db.distributedLockNoWaitEnabled (default false) for opt-in activation
• Exception Handling: Extended ignoreSQLException() to recognize:
  • MySQL 8.0+ error code 3572 (ER_LOCK_NOWAIT)
  • PostgreSQL SQLState 55P03 (lock_not_available)
  • Oracle error code 54 (ORA-00054)
• Backward Compatibility: Databases without NOWAIT support (SQL Server, MySQL 5.x, MariaDB) fall back to blocking behavior
• Tests: Added comprehensive unit tests for SQL generation and exception handling

Test Plan

• Core SQL factory tests pass (17 tests, 0 failures)
• Spotless formatting check passes
• New dialect implementations generate correct NOWAIT SQL
• Default implementations fall back to blocking SQL
• Exception handling correctly identifies NOWAIT error codes
• Integration tests with real databases (MySQL 8.0+, PostgreSQL, Oracle) - requires dbCaseEnabled=true

Configuration

To enable NOWAIT on supported databases, add to application.yml:

store:
  db:
    distributedLockNoWaitEnabled: true

Note: Only enable on MySQL 8.0+, PostgreSQL, or Oracle. MySQL 5.x/MariaDB do not support NOWAIT and will raise syntax errors if enabled.

Related Issue

Resolves #7993

🤖 Generated with Claude Code

[Copilot]

Pull request overview

Implements an opt-in “NOWAIT” (fast-fail) acquisition path for the database-backed distributed lock, reducing thread blocking under high lock contention by using dialect-specific SELECT ... FOR UPDATE NOWAIT SQL and recognizing the corresponding vendor errors as expected contention signals.

Changes:

• Adds getSelectDistributeForUpdateNoWaitSql() to DistributedLockSql with a default fallback to the blocking variant.
• Introduces MySQL/PostgreSQL/Oracle distributed-lock SQL dialects that append FOR UPDATE NOWAIT, and wires DataBaseDistributedLocker to choose NOWAIT SQL when store.db.distributedLockNoWaitEnabled=true.
• Extends ignoreSQLException() to treat NOWAIT contention signals (MySQL 3572, Oracle 54, PostgreSQL SQLState 55P03) as ignorable fast-fail outcomes, plus adds unit tests for SQL generation and exception matching.

Reviewed changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
server/src/main/java/org/apache/seata/server/storage/db/lock/DataBaseDistributedLocker.java	Adds config-driven NOWAIT path for lock-row selection and recognizes NOWAIT contention SQLExceptions.
server/src/test/java/org/apache/seata/server/storage/db/lock/DataBaseDistributedLockerTest.java	Adds tests for NOWAIT exception handling and verifying NOWAIT vs blocking SQL usage.
core/src/main/java/org/apache/seata/core/store/db/sql/distributed/lock/DistributedLockSql.java	Extends SPI with a default NOWAIT SQL method that falls back to legacy behavior.
core/src/main/java/org/apache/seata/core/store/db/sql/distributed/lock/MysqlDistributedLockSql.java	MySQL dialect that generates FOR UPDATE NOWAIT.
core/src/main/java/org/apache/seata/core/store/db/sql/distributed/lock/PostgresqlDistributedLockSql.java	PostgreSQL dialect that generates FOR UPDATE NOWAIT.
core/src/main/java/org/apache/seata/core/store/db/sql/distributed/lock/OracleDistributedLockSql.java	Oracle dialect that generates FOR UPDATE NOWAIT.
core/src/main/resources/META-INF/services/org.apache.seata.core.store.db.sql.distributed.lock.DistributedLockSql	Registers new dialect implementations for SPI discovery.
core/src/test/java/org/apache/seata/core/store/db/sql/distributed/lock/DistributedLockSqlNoWaitTest.java	Adds unit tests validating dialect NOWAIT SQL and default fallback behavior.
core/src/test/java/org/apache/seata/core/store/db/sql/distributed/lock/DistributedLockSqlFactoryTest.java	Updates factory tests to assert MySQL/PostgreSQL/Oracle map to the new dialect classes.
common/src/main/java/org/apache/seata/common/DefaultValues.java	Adds default value for the new NOWAIT enablement configuration (disabled by default).
common/src/main/java/org/apache/seata/common/ConfigurationKeys.java	Adds the store.db.distributedLockNoWaitEnabled configuration key.

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