Performance improvements when query includes sys.indexes.is_primary_k…

…ey predicate (babelfish-for-postgresql#2917)

Previously for a query we were observing a performance degradation when it included a join between sys.indexes, sys.index_columns, sys.columns, sys.tables, and sys.schemas views with sys.indexes.is_primary_key = 1 predicate in where clause. We identified that there was the issue with a case statement due to which there was an incorrect row estimation so we have implemented a direct cast by defining new IMPLICIT cast without function from boolean to sys.bit.
Another issue was the use of redundant has_schema_privilege in sys views and functions, as we explicitly grant usage to public beforehand, so we have removed the redundant has_schema_privilege check.

Issues Resolved: BABEL-5215

Signed-off-by: Tanya Gupta <[email protected]>

contrib/babelfishpg_common/sql/bit.sql

@@ -501,3 +501,6 @@ LANGUAGE C IMMUTABLE STRICT PARALLEL SAFE;
 
 CREATE CAST (sys.VARCHAR AS sys.BIT)
 WITH FUNCTION sys.varchar2bit(sys.VARCHAR) AS IMPLICIT;
+
+CREATE CAST (bool AS sys.BIT)
+WITHOUT FUNCTION AS IMPLICIT;

contrib/babelfishpg_common/sql/upgrades/babelfish_common_helper--4.3.0--4.4.0.sql

@@ -63,6 +63,24 @@ WITH FUNCTION sys.varchar2time(sys.VARCHAR, INT4) AS IMPLICIT;
 
 CALL sys.babelfish_drop_deprecated_object('function', 'sys', 'varchar2time_deprecated_4_4_0');
 
+-- bool bit cast
+DO $$
+DECLARE 
+    sys_oid Oid;
+    pg_catalog_oid Oid;
+    bool_oid Oid;
+    bit_oid Oid;
+BEGIN
+  sys_oid := (SELECT oid FROM pg_namespace WHERE pg_namespace.nspname ='sys');
+  pg_catalog_oid := (SELECT oid FROM pg_namespace WHERE pg_namespace.nspname ='pg_catalog');
+  bool_oid := (SELECT oid FROM pg_type WHERE pg_type.typname ='bool' AND pg_type.typnamespace = pg_catalog_oid);
+  bit_oid := (SELECT oid FROM pg_type WHERE pg_type.typname ='bit' AND pg_type.typnamespace = sys_oid);
+  IF (SELECT COUNT(*) FROM pg_cast WHERE pg_cast.castsource = bool_oid AND pg_cast.casttarget = bit_oid) = 0 THEN
+      CREATE CAST (bool AS sys.BIT)
+      WITHOUT FUNCTION AS IMPLICIT;
+  END IF;
+END $$;
+
 -- Drops the temporary procedure used by the upgrade script.
 -- Please have this be one of the last statements executed in this upgrade script.
 DROP PROCEDURE sys.babelfish_drop_deprecated_object(varchar, varchar, varchar);

contrib/babelfishpg_tsql/sql/babelfishpg_tsql.sql

@@ -908,7 +908,6 @@ CAST(NULL AS varchar(254)) AS remarks
 FROM pg_catalog.pg_class AS t1, sys.pg_namespace_ext AS t2, sys.schemas AS t3
 WHERE t1.relnamespace = t3.schema_id AND t1.relnamespace = t2.oid AND t1.relkind IN ('r','p','v','m') 
 AND t1.relispartition = false
-AND has_schema_privilege(t1.relnamespace, 'USAGE')
 AND has_table_privilege(t1.oid, 'SELECT,INSERT,UPDATE,DELETE,TRUNCATE,TRIGGER');
 GRANT SELECT ON sys.sp_tables_view TO PUBLIC;
 
@@ -1499,8 +1498,7 @@ LEFT JOIN sys.types AS t1 ON a.atttypid = t1.user_type_id
 LEFT JOIN sys.sp_datatype_info_helper(2::smallint, false) AS t6 ON T.typname = t6.pg_type_name OR T.typname = t6.type_name --need in order to get accurate DATA_TYPE value
 , sys.translate_pg_type_to_tsql(t1.user_type_id) AS tsql_type_name
 , sys.translate_pg_type_to_tsql(t1.system_type_id) AS tsql_base_type_name
-WHERE has_schema_privilege(s1.schema_id, 'USAGE')
-AND X.indislive ;
+WHERE X.indislive ;
 
 GRANT SELECT ON sys.sp_special_columns_view TO PUBLIC; 
 
@@ -1858,7 +1856,6 @@ FROM pg_catalog.pg_proc p
 
 INNER JOIN sys.schemas s1 ON p.pronamespace = s1.schema_id 
 INNER JOIN sys.databases d ON d.database_id = sys.db_id()
-WHERE has_schema_privilege(s1.schema_id, 'USAGE')
 
 UNION