postgresql - Postgres : TRUNCATE and COPY in one transaction

Question

我需要在 Postgres 9.4 中执行以下事务:

BEGIN TRANSACTION;
    TRUNCATE TestTable;
    COPY TestTable FROM '/DATAforTestTable' DELIMITER ',' CSV;
END TRANSACTION;

用户必须在执行交易时对 TestTable 中的“旧”数据具有读取权限，而无需等待交易结束。是否可以？或者我必须通过复制和重命名表格来完成？

Answer 1

来自manual :

TRUNCATE acquires an ACCESS EXCLUSIVE lock on each table it operates on, which blocks all other concurrent operations on the table.

使用删除

begin;
delete from t;