Postgresql 中文操作指南
54.16. pg_prepared_xacts #
视图 pg_prepared_xacts 显示了当前为两阶段提交准备的事务信息（有关详细信息，请参阅 PREPARE TRANSACTION ）。
The view pg_prepared_xacts displays information about transactions that are currently prepared for two-phase commit (see PREPARE TRANSACTION for details).
pg_prepared_xacts 每笔已准备的事务包含一行。当事务提交或回滚时，会删除该条目。
pg_prepared_xacts contains one row per prepared transaction. An entry is removed when the transaction is committed or rolled back.
Table 54.16. pg_prepared_xacts Columns
Table 54.16. pg_prepared_xacts Columns
Column Type Description |
transaction xid Numeric transaction identifier of the prepared transaction |
gid text Global transaction identifier that was assigned to the transaction |
prepared timestamptz Time at which the transaction was prepared for commit |
owner name (references pg_authid.rolname) Name of the user that executed the transaction |
database name (references pg_database.datname) Name of the database in which the transaction was executed |
当访问 pg_prepared_xacts 视图时，将暂时锁定内部事务管理器数据结构，并复制一份以供视图显示。这意味着，该视图可以生成一组一致的结果，同时又不会长时间阻塞正常操作。不过，如果频繁访问此视图，则可能会对数据库的性能产生一定的影响。
When the pg_prepared_xacts view is accessed, the internal transaction manager data structures are momentarily locked, and a copy is made for the view to display. This ensures that the view produces a consistent set of results, while not blocking normal operations longer than necessary. Nonetheless there could be some impact on database performance if this view is frequently accessed.