摘要：
Oracle 的SQL文，可以强制指定各种 hint。但是在PostgreSQL中是不支持的。其wiki 是这样说的：http://wiki.postgresql.org/wiki/OptimizerHintsDiscussionWe are not interested in implementing hints in the exact ways they are commonly implemented on other databases. Proposals based on "because they've got them" will not be w 阅读全文
摘要：
看到了其源代码中的一段注释，似乎认识又提高了一层：/* * INTERFACE ROUTINES * ExecInitNode - initialize a plan node and its subplans * ExecProcNode - get a tuple by executing the plan node * ExecEndNode - shut down a plan node and its subplans * * NOTES * T... 阅读全文
摘要：
PostgreSQL中，有一种 tidscan。当我在使用cursor的时候，会用到此种scan：[postgres@lex pgsql]$ cat ./data/test.sqlCREATE OR REPLACE Function FindCourse ( name_in IN varchar ) RETURNS integer LANGUAGE plpgsql AS $$DECLARE cnumber integer; c1 CURSOR FOR SELECT course_number, instructor from course_t... 阅读全文