Create a "fast path" for acquiring weak relation locks.

When an AccessShareLock, RowShareLock, or RowExclusiveLock is requested
on an unshared database relation, and we can verify that no conflicting
locks can possibly be present, record the lock in a per-backend queue,
stored within the PGPROC, rather than in the primary lock table.  This
eliminates a great deal of contention on the lock manager LWLocks.

This patch also refactors the interface between GetLockStatusData() and
pg_lock_status() to be a bit more abstract, so that we don't rely so
heavily on the lock manager's internal representation details.  The new
fast path lock structures don't have a LOCK or PROCLOCK structure to
return, so we mustn't depend on that for purposes of listing outstanding
locks.

Review by Jeff Davis.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index 20cdc39752d..336df52db8c 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -1284,7 +1284,7 @@ SELECT viewname, definition FROM pg_views WHERE schemaname <> 'information_schem
  pg_cursors                      | SELECT c.name, c.statement, c.is_holdable, c.is_binary, c.is_scrollable, c.creation_time FROM pg_cursor() c(name, statement, is_holdable, is_binary, is_scrollable, creation_time);
  pg_group                        | SELECT pg_authid.rolname AS groname, pg_authid.oid AS grosysid, ARRAY(SELECT pg_auth_members.member FROM pg_auth_members WHERE (pg_auth_members.roleid = pg_authid.oid)) AS grolist FROM pg_authid WHERE (NOT pg_authid.rolcanlogin);
  pg_indexes                      | SELECT n.nspname AS schemaname, c.relname AS tablename, i.relname AS indexname, t.spcname AS tablespace, 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))) LEFT JOIN pg_tablespace t ON ((t.oid = i.reltablespace))) WHERE ((c.relkind = 'r'::"char") AND (i.relkind = 'i'::"char"));
- pg_locks                        | SELECT l.locktype, l.database, l.relation, l.page, l.tuple, l.virtualxid, l.transactionid, l.classid, l.objid, l.objsubid, l.virtualtransaction, l.pid, l.mode, l.granted FROM pg_lock_status() l(locktype, database, relation, page, tuple, virtualxid, transactionid, classid, objid, objsubid, virtualtransaction, pid, mode, granted);
+ pg_locks                        | SELECT l.locktype, l.database, l.relation, l.page, l.tuple, l.virtualxid, l.transactionid, l.classid, l.objid, l.objsubid, l.virtualtransaction, l.pid, l.mode, l.granted, l.fastpath FROM pg_lock_status() l(locktype, database, relation, page, tuple, virtualxid, transactionid, classid, objid, objsubid, virtualtransaction, pid, mode, granted, fastpath);
  pg_prepared_statements          | SELECT p.name, p.statement, p.prepare_time, p.parameter_types, p.from_sql FROM pg_prepared_statement() p(name, statement, prepare_time, parameter_types, from_sql);
  pg_prepared_xacts               | SELECT p.transaction, p.gid, p.prepared, u.rolname AS owner, d.datname AS database FROM ((pg_prepared_xact() p(transaction, gid, prepared, ownerid, dbid) LEFT JOIN pg_authid u ON ((p.ownerid = u.oid))) LEFT JOIN pg_database d ON ((p.dbid = d.oid)));
  pg_roles                        | SELECT pg_authid.rolname, pg_authid.rolsuper, pg_authid.rolinherit, pg_authid.rolcreaterole, pg_authid.rolcreatedb, pg_authid.rolcatupdate, pg_authid.rolcanlogin, pg_authid.rolreplication, pg_authid.rolconnlimit, '********'::text AS rolpassword, pg_authid.rolvaliduntil, s.setconfig AS rolconfig, pg_authid.oid FROM (pg_authid LEFT JOIN pg_db_role_setting s ON (((pg_authid.oid = s.setrole) AND (s.setdatabase = (0)::oid))));