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mirror of https://github.com/postgres/postgres.git synced 2025-07-28 23:42:10 +03:00

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
This commit is contained in:
Bruce Momjian
2002-08-15 02:51:27 +00:00
parent 4c4854c458
commit 45e2544584
10 changed files with 372 additions and 220 deletions

View File

@ -1269,6 +1269,7 @@ SELECT viewname, definition FROM pg_views ORDER BY viewname;
iexit | SELECT ih.name, ih.thepath, interpt_pp(ih.thepath, r.thepath) AS exit FROM ihighway ih, ramp r WHERE (ih.thepath ## r.thepath);
pg_indexes | SELECT n.nspname AS schemaname, c.relname AS tablename, i.relname AS indexname, pg_get_indexdef(i.oid) AS indexdef FROM (((pg_index x JOIN pg_class c ON ((c.oid = x.indrelid))) JOIN pg_class i ON ((i.oid = x.indexrelid))) LEFT JOIN pg_namespace n ON ((n.oid = c.relnamespace))) WHERE ((c.relkind = 'r'::"char") AND (i.relkind = 'i'::"char"));
pg_rules | SELECT n.nspname AS schemaname, c.relname AS tablename, r.rulename, pg_get_ruledef(r.oid) AS definition FROM ((pg_rewrite r JOIN pg_class c ON ((c.oid = r.ev_class))) LEFT JOIN pg_namespace n ON ((n.oid = c.relnamespace))) WHERE (r.rulename <> '_RETURN'::name);
pg_settings | SELECT a.name, a.setting FROM pg_show_all_settings() a;
pg_stat_activity | SELECT d.oid AS datid, d.datname, pg_stat_get_backend_pid(s.backendid) AS procpid, pg_stat_get_backend_userid(s.backendid) AS usesysid, u.usename, pg_stat_get_backend_activity(s.backendid) AS current_query FROM pg_database d, (SELECT pg_stat_get_backend_idset() AS backendid) s, pg_shadow u WHERE ((pg_stat_get_backend_dbid(s.backendid) = d.oid) AND (pg_stat_get_backend_userid(s.backendid) = u.usesysid));
pg_stat_all_indexes | SELECT c.oid AS relid, i.oid AS indexrelid, n.nspname AS schemaname, c.relname, i.relname AS indexrelname, pg_stat_get_numscans(i.oid) AS idx_scan, pg_stat_get_tuples_returned(i.oid) AS idx_tup_read, pg_stat_get_tuples_fetched(i.oid) AS idx_tup_fetch FROM (((pg_class c JOIN pg_index x ON ((c.oid = x.indrelid))) JOIN pg_class i ON ((i.oid = x.indexrelid))) LEFT JOIN pg_namespace n ON ((n.oid = c.relnamespace))) WHERE (c.relkind = 'r'::"char");
pg_stat_all_tables | SELECT c.oid AS relid, n.nspname AS schemaname, c.relname, pg_stat_get_numscans(c.oid) AS seq_scan, pg_stat_get_tuples_returned(c.oid) AS seq_tup_read, sum(pg_stat_get_numscans(i.indexrelid)) AS idx_scan, sum(pg_stat_get_tuples_fetched(i.indexrelid)) AS idx_tup_fetch, pg_stat_get_tuples_inserted(c.oid) AS n_tup_ins, pg_stat_get_tuples_updated(c.oid) AS n_tup_upd, pg_stat_get_tuples_deleted(c.oid) AS n_tup_del FROM ((pg_class c LEFT JOIN pg_index i ON ((c.oid = i.indrelid))) LEFT JOIN pg_namespace n ON ((n.oid = c.relnamespace))) WHERE (c.relkind = 'r'::"char") GROUP BY c.oid, n.nspname, c.relname;
@ -1304,12 +1305,14 @@ SELECT viewname, definition FROM pg_views ORDER BY viewname;
shoelace_obsolete | SELECT shoelace.sl_name, shoelace.sl_avail, shoelace.sl_color, shoelace.sl_len, shoelace.sl_unit, shoelace.sl_len_cm FROM shoelace WHERE (NOT (EXISTS (SELECT shoe.shoename FROM shoe WHERE (shoe.slcolor = shoelace.sl_color))));
street | SELECT r.name, r.thepath, c.cname FROM ONLY road r, real_city c WHERE (c.outline ## r.thepath);
toyemp | SELECT emp.name, emp.age, emp."location", (12 * emp.salary) AS annualsal FROM emp;
(38 rows)
(39 rows)
SELECT tablename, rulename, definition FROM pg_rules
ORDER BY tablename, rulename;
tablename | rulename | definition
---------------+-----------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
pg_settings | pg_settings_n | CREATE RULE pg_settings_n AS ON UPDATE TO pg_settings DO INSTEAD NOTHING;
pg_settings | pg_settings_u | CREATE RULE pg_settings_u AS ON UPDATE TO pg_settings WHERE (new.name = old.name) DO SELECT set_config(old.name, new.setting, 'f'::boolean) AS set_config;
rtest_emp | rtest_emp_del | CREATE RULE rtest_emp_del AS ON DELETE TO rtest_emp DO INSERT INTO rtest_emplog (ename, who, "action", newsal, oldsal) VALUES (old.ename, "current_user"(), 'fired '::bpchar, '$0.00'::money, old.salary);
rtest_emp | rtest_emp_ins | CREATE RULE rtest_emp_ins AS ON INSERT TO rtest_emp DO INSERT INTO rtest_emplog (ename, who, "action", newsal, oldsal) VALUES (new.ename, "current_user"(), 'hired '::bpchar, new.salary, '$0.00'::money);
rtest_emp | rtest_emp_upd | CREATE RULE rtest_emp_upd AS ON UPDATE TO rtest_emp WHERE (new.salary <> old.salary) DO INSERT INTO rtest_emplog (ename, who, "action", newsal, oldsal) VALUES (new.ename, "current_user"(), 'honored '::bpchar, new.salary, old.salary);
@ -1337,5 +1340,5 @@ SELECT tablename, rulename, definition FROM pg_rules
shoelace | shoelace_upd | CREATE RULE shoelace_upd AS ON UPDATE TO shoelace DO INSTEAD UPDATE shoelace_data SET sl_name = new.sl_name, sl_avail = new.sl_avail, sl_color = new.sl_color, sl_len = new.sl_len, sl_unit = new.sl_unit WHERE (shoelace_data.sl_name = old.sl_name);
shoelace_data | log_shoelace | CREATE RULE log_shoelace AS ON UPDATE TO shoelace_data WHERE (new.sl_avail <> old.sl_avail) DO INSERT INTO shoelace_log (sl_name, sl_avail, log_who, log_when) VALUES (new.sl_name, new.sl_avail, 'Al Bundy'::name, 'Thu Jan 01 00:00:00 1970'::timestamp without time zone);
shoelace_ok | shoelace_ok_ins | CREATE RULE shoelace_ok_ins AS ON INSERT TO shoelace_ok DO INSTEAD UPDATE shoelace SET sl_avail = (shoelace.sl_avail + new.ok_quant) WHERE (shoelace.sl_name = new.ok_name);
(27 rows)
(29 rows)