release: v0.5.1 — 存储后端生产级硬化（CRC-32/全库加密/WAL分片/页面化存储/多标签页锁/e2e）+ 深度审查修复（假实现接线/死代码清理）

src/sql/parser.ts

@@ -72,6 +72,19 @@ export class Parser {
         return this.parseCommit();
       case TokenType.ROLLBACK:
         return this.parseRollback();
+      // v0.5.1: 维护语句入口
+      case TokenType.EXPLAIN:
+        return this.parseExplain();
+      case TokenType.ANALYZE:
+        return this.parseAnalyze();
+      case TokenType.REINDEX:
+        return this.parseReindex();
+      case TokenType.VACUUM:
+        return this.parseVacuum();
+      case TokenType.SAVEPOINT:
+        return this.parseSavepoint();
+      case TokenType.RELEASE:
+        return this.parseSavepoint();
       default:
         throw this.error(`Unexpected token "${this.curToken.value}"`);
     }
@@ -95,6 +108,57 @@ export class Parser {
     return statements;
   }
 
+  // ---- 维护语句（v0.5.1） ----
+
+  /** EXPLAIN <statement> — 输出查询计划 */
+  private parseExplain(): import('../query/ast').ExplainStatement {
+    this.expect(TokenType.EXPLAIN);
+    if (this.curTokenIs(TokenType.EXPLAIN)) {
+      throw this.error('Nested EXPLAIN is not allowed');
+    }
+    const query = this.parseStatement();
+    return { type: 'EXPLAIN', query };
+  }
+
+  /** ANALYZE [TABLE] name — 收集表统计信息 */
+  private parseAnalyze(): import('../query/ast').AnalyzeStatement {
+    this.expect(TokenType.ANALYZE);
+    if (this._isKeywordAsIdent() && this.curToken.value.toUpperCase() === 'TABLE') {
+      this.nextToken();
+    }
+    return { type: 'ANALYZE', table: this.expectIdentifier('table name') };
+  }
+
+  /** REINDEX [TABLE] name — 重建表二级索引 */
+  private parseReindex(): import('../query/ast').ReindexStatement {
+    this.expect(TokenType.REINDEX);
+    if (this._isKeywordAsIdent() && this.curToken.value.toUpperCase() === 'TABLE') {
+      this.nextToken();
+    }
+    return { type: 'REINDEX', table: this.expectIdentifier('table name') };
+  }
+
+  /** VACUUM — 压缩 LSM + 清理碎片 */
+  private parseVacuum(): import('../query/ast').VacuumStatement {
+    this.expect(TokenType.VACUUM);
+    return { type: 'VACUUM' };
+  }
+
+  /** SAVEPOINT name | RELEASE [SAVEPOINT] name */
+  private parseSavepoint(): import('../query/ast').SavepointStatement {
+    let action: 'SAVE' | 'ROLLBACK' | 'RELEASE';
+    if (this.curTokenIs(TokenType.RELEASE)) {
+      action = 'RELEASE';
+      this.nextToken();
+    } else {
+      action = 'SAVE';
+      this.expect(TokenType.SAVEPOINT);
+    }
+    // 可选 SAVEPOINT 关键字（RELEASE SAVEPOINT name）
+    if (this.curTokenIs(TokenType.SAVEPOINT)) this.nextToken();
+    return { type: 'SAVEPOINT', name: this.expectIdentifier('savepoint name'), action };
+  }
+
   // ---- 事务语句 ----
 
   private parseBegin(): BeginTransactionStatement {
@@ -114,10 +178,22 @@ export class Parser {
     return { type: 'COMMIT' };
   }
 
-  private parseRollback(): RollbackTransactionStatement {
+  /** ROLLBACK [TRANSACTION] | ROLLBACK TO [SAVEPOINT] name（v0.5.1） */
+  private parseRollback(): Statement {
     this.expect(TokenType.ROLLBACK);
     if (this._isKeywordAsIdent() && this.curToken.value.toUpperCase() === 'TRANSACTION') {
       this.nextToken();
+      return { type: 'ROLLBACK' };
+    }
+    // ROLLBACK TO [SAVEPOINT] name
+    if (this.curTokenIs(TokenType.TO) ||
+      (this._isKeywordAsIdent() && this.curToken.value.toUpperCase() === 'TO')) {
+      this.nextToken();
+      if (this.curTokenIs(TokenType.SAVEPOINT) ||
+        (this._isKeywordAsIdent() && this.curToken.value.toUpperCase() === 'SAVEPOINT')) {
+        this.nextToken();
+      }
+      return { type: 'SAVEPOINT', name: this.expectIdentifier('savepoint name'), action: 'ROLLBACK' };
     }
     return { type: 'ROLLBACK' };
   }