postgresql select for update
PostgreSQL doesn't remember any information about modified rows in memory, so there is no limit on the number of rows locked at one time. However, locking a row might cause a disk write, e.g., SELECT FOR UPDATE modifies selected rows to mark them lock,FOR UPDATE and FOR SHARE. Although FOR UPDATE appears in the SQL standard, the standard allows it only as an option of DECLARE CURSOR. PostgreSQL allows it in any SELECT query as well as in sub-SELECTs, but this is an extension. The FOR SHARE variant, and
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 postgresql select for update 相關參考資料
PostgreSQL: Documentation: 9.5: SELECT
You must have SELECT privilege on each column used in a SELECT command. The use of FOR NO KEY UPDATE, FOR UPDATE, FOR SHARE or FOR KEY ... https://www.postgresql.org PostgreSQL: Documentation: 9.4: Explicit Locking
PostgreSQL doesn't remember any information about modified rows in memory, so there is no limit on the number of rows locked at one time. However, locking a row might cause a disk write, e.g., SEL... https://www.postgresql.org PostgreSQL: Documentation: 9.0: SELECT
FOR UPDATE and FOR SHARE. Although FOR UPDATE appears in the SQL standard, the standard allows it only as an option of DECLARE CURSOR. PostgreSQL allows it in any SELECT query as well as in sub-SELECT... https://www.postgresql.org PostgreSQL: Documentation: 9.5: UPDATE
The WITH clause allows you to specify one or more subqueries that can be referenced by name in the UPDATE query. See Section 7.8 and SELECT for details. https://www.postgresql.org PostgreSQL: Documentation: 9.6: SELECT
You must have SELECT privilege on each column used in a SELECT command. The use of FOR NO KEY UPDATE, FOR UPDATE, FOR SHARE or FOR KEY ... https://www.postgresql.org PostgreSQL: Documentation: 9.1: SELECT
If FOR UPDATE or FOR SHARE is specified, the SELECT statement locks the selected rows against concurrent updates. (See FOR UPDATE/FOR SHARE ... https://www.postgresql.org postgresql - Postgres SELECT ... FOR UPDATE in functions - Stack ...
Does it matter which columns I select? No, it doesn't matter. Even if SELECT 1 FROM table WHERE ... FOR UPDATE is used, the query locks all ... https://stackoverflow.com Selecting for Share and Update in PostgreSQL - Shiroyasha
Other transactions can update or delete the data you just queried. PostgreSQL offers additional select statements that lock on read and provide ... http://shiroyasha.io |