t i p : \color{red}{tip:}tip: 如果服务器在备份期间崩溃,则可能无法重新启动,直到从 PGDATA 目录中手动删除 backup_label 文件。 再次以有权运行 pg_stop_backup 的用户(超级用户,或已被授予 EXECUTE 功能的用户)连接到数据库,并发出命令: SELECT pg_stop_backup(); 1 此函数终止备份模式并执行自动切换...
None - By default, psycopg2’s extensions are not used, and the usual cursor.executemany() method is used when invoking batches of statements. ‘batch’ - Uses psycopg2.extras.execute_batch so that multiple copies of a SQL query, each one corresponding to a parameter set passed to executemany...
FOUND is set this way when the loop exits; inside the execution of the loop, FOUND is not modified by the loop statement, although it might be changed by the execution of other statements within the loop body. RETURN QUERY and RETURN QUERY EXECUTE statements set FOUND true if the query ...
> The commit occurs when the statement completes or the next execute occurs, whichever comes first. In the case of statementsreturning a ResultSet object, the statement completes when the last row of the ResultSet object has been retrievedor the ResultSet object has been closed. In advanced ca...
Note that this is similar to the process Doltgres uses to execute queries, where we parse a Postgres query into an AST, then turn that into an equivalent MySQL AST for execution by Dolt's query engine. Here's the entry point for transforming a MySQL query into a Postgres query. Our fu...
execute_sql Executes SQL statements on the database, with read-only limitations when connected in restricted mode. explain_query Gets the execution plan for a SQL query describing how PostgreSQL will process it and exposing the query planner's cost model. Can be invoked with hypothetical indexes ...
SQL is a declarative language, and the Postgres query planner will decide the most efficient way to execute a query. However, plan selection is based on statistics, configuration settings, and heuristics—not a crystal ball. Sometimes there's a substantial gap between what the planner thinks is...
Execute these steps in two different transactions. Both these steps take DDL lock only on the table and hence can be run even when one or more nodes are down. But to validate a constraint, BDR must ensure that: All nodes in the cluster see the ADD CONSTRAINT command. The node validatin...
Implementing a GUI can enable developers to execute repeatable SQL procedures without exposing the SQL to the database administrator. Of course, a GUI is also only as good as its design and engineering. A simple GUI may be akin to a spreadsheet that maps to the database system. However, a...
Executes multiple SQL statements atomically. Description: Execute SQL sequence in a transaction, with step logging/progress. Parameters: operations (array of {statement, params}), dbAlias (string, opt). Context Usage: log.info/debug/error, reportProgress, access session. Returns: JSON string summari...