Store original name for Babelfish indexes (#3429)

In Babelfish, index names are generated by first calculating hash of given original index name
and table name concatenated together and then concatenating index name, table name and
this hash together once again to form a 64 character long identifier.
But this name is not intuitive for users as it looks different from what user specified while
creating the index.
To address this issue, this commit adds ability to store original index name as a reloption for a
given index and show that stored original name in the catalog views, like sys.indexes.
This CR extends this solution to also store original index names for partitioned indexes.
Additionally, support renaming of indexes using `sp_rename` so that existing indexes can be
renamed so that their original names get stored in the catalog.
 
Task: BABEL-1517
Signed-off-by: Rishabh Tanwar <[email protected]>

contrib/babelfishpg_tsql/sql/babelfishpg_tsql.sql

@@ -2985,11 +2985,18 @@ BEGIN
 	DECLARE @row_count INT;
 	SELECT @row_count = COUNT(*) FROM #sp_rename_temptable2;
 
-	IF @objtype = 'COLUMN'
+	IF @objtype = 'COLUMN' OR @objtype = 'INDEX'
 		BEGIN
 			IF @row_count = 1
 				BEGIN
-					THROW 33557097, N'Either the parameter @objname is ambiguous or the claimed @objtype (COLUMN) is wrong.', 1;
+					IF @objtype = 'COLUMN'
+						BEGIN
+							THROW 33557097, N'Either the parameter @objname is ambiguous or the claimed @objtype (COLUMN) is wrong.', 1;
+						END;
+					ELSE
+						BEGIN
+							THROW 33557097, N'Either the parameter @objname is ambiguous or the claimed @objtype (INDEX) is wrong.', 1;
+						END
 				END
 			ELSE IF @row_count > 4
 				BEGIN
@@ -3071,10 +3078,6 @@ BEGIN
 		BEGIN
 			THROW 33557097, N'Please provide @objtype that is supported in Babelfish', 1;
 		END
-	ELSE IF @objtype = 'INDEX'
-		BEGIN
-			THROW 33557097, N'Feature not supported: renaming object type Index', 1;
-		END
 	ELSE IF @objtype = 'STATISTICS'
 		BEGIN
 			THROW 33557097, N'Feature not supported: renaming object type Statistics', 1;
@@ -3104,6 +3107,24 @@ BEGIN
 						END
 					SET @currtype = 'CO';
 				END
+			ELSE IF @objtype = 'INDEX'
+				BEGIN
+					DECLARE @relid INT = 0;
+					DECLARE @index_count INT;
+					SELECT @relid = object_id FROM sys.objects o1 INNER JOIN sys.schemas s1 ON o1.schema_id = s1.schema_id 
+						WHERE s1.name = @schemaname AND o1.name = @curr_relname;
+					IF @relid = 0
+						BEGIN
+							THROW 33557097, N'There is no object with the given @objname.', 1;
+						END
+					SELECT @index_count = COUNT(*) FROM pg_index i JOIN pg_class c ON i.indexrelid = c.oid
+						WHERE i.indrelid = @relid AND c.relname = sys.babelfish_construct_unique_index_name(@subname, @curr_relname);
+					IF @index_count < 0
+						BEGIN
+							THROW 33557097, N'There is no object with the given @objname.', 1;
+						END
+					SET @currtype = 'IX';
+				END
 			ELSE IF @objtype = 'USERDATATYPE'
 				BEGIN
 					DECLARE @alias_count INT;

contrib/babelfishpg_tsql/sql/sys_function_helpers.sql

@@ -11431,3 +11431,7 @@ LANGUAGE C IMMUTABLE STRICT PARALLEL SAFE;
 CREATE OR REPLACE FUNCTION sys.babelfish_split_identifier(IN identifier VARCHAR, OUT value VARCHAR)
 RETURNS SETOF VARCHAR AS 'babelfishpg_tsql', 'split_identifier_internal'
 LANGUAGE C IMMUTABLE STRICT PARALLEL SAFE;
+
+CREATE OR REPLACE FUNCTION sys.babelfish_construct_unique_index_name(index_name TEXT, table_name TEXT)
+RETURNS TEXT AS 'babelfishpg_tsql', 'bbf_construct_unique_index_name'
+LANGUAGE C IMMUTABLE STRICT PARALLEL SAFE;

contrib/babelfishpg_tsql/sql/sys_views.sql

@@ -834,7 +834,16 @@ with index_id_map as MATERIALIZED(
 )
 select
   cast(X.indrelid as int) as object_id
-  , cast(I.relname as sys.sysname) as name
+  , cast(
+		coalesce(
+			(select pg_catalog.string_agg(
+				case
+					when option like 'bbf_original_rel_name=%' then substring(option, 23 /* prefix length */)
+					else null
+				end, ',')
+			from unnest(I.reloptions) as option),
+			I.relname)
+		AS sys.sysname) AS name
   , cast(case when X.indisclustered then 1 else 2 end as sys.tinyint) as type
   , cast(case when X.indisclustered then 'CLUSTERED' else 'NONCLUSTERED' end as sys.nvarchar(60)) as type_desc
   , cast(X.indisunique as sys.bit) as is_unique