postgres

Commit Graph

Author	SHA1	Message	Date
Bruce Momjian	e50f52a074	pgindent run.	24 years ago
Bruce Momjian	6aa4482f2f	Attached is an update to contrib/tablefunc. It introduces a new function, connectby(), which can serve as a reference implementation for the changes made in the last few days -- namely the ability of a function to return an entire tuplestore, and the ability of a function to make use of the query provided "expected" tuple description. Description: connectby(text relname, text keyid_fld, text parent_keyid_fld, text start_with, int max_depth [, text branch_delim]) - returns keyid, parent_keyid, level, and an optional branch string - requires anonymous composite type syntax in the FROM clause. See the instructions in the documentation below. Joe Conway	24 years ago
Bruce Momjian	45e2544584	As discussed on several occasions previously, the new anonymous composite type capability makes it possible to create a system view based on a table function in a way that is hopefully palatable to everyone. The attached patch takes advantage of this, moving show_all_settings() from contrib/tablefunc into the backend (renamed all_settings(). It is defined as a builtin returning type RECORD. During initdb a system view is created to expose the same information presently available through SHOW ALL. For example: test=# select * from pg_settings where name like '%debug%'; name \| setting -----------------------+--------- debug_assertions \| on debug_pretty_print \| off debug_print_parse \| off debug_print_plan \| off debug_print_query \| off debug_print_rewritten \| off wal_debug \| 0 (7 rows) Additionally during initdb two rules are created which make it possible to change settings by updating the system view -- a "virtual table" as Tom put it. Here's an example: Joe Conway	24 years ago
Bruce Momjian	41f862ba87	As mentioned above, here is my contrib/tablefunc patch. It includes three functions which exercise the tablefunc API. show_all_settings() - returns the same information as SHOW ALL, but as a query result normal_rand(int numvals, float8 mean, float8 stddev, int seed) - returns a set of normally distributed float8 values - This routine implements Algorithm P (Polar method for normal deviates) from Knuth's _The_Art_of_Computer_Programming_, Volume 2, 3rd ed., pages 122-126. Knuth cites his source as "The polar method", G. E. P. Box, M. E. Muller, and G. Marsaglia, _Annals_Math,_Stat._ 29 (1958), 610-611. crosstabN(text sql) - returns a set of row_name plus N category value columns - crosstab2(), crosstab3(), and crosstab4() are defined for you, but you can create additional crosstab functions per directions in the README. Joe Conway	24 years ago

4 Commits (fd972e7f7edeee5eb410070e204a11a197703cf9)