Support repeatable read and serializable isolation level (#1695)

Currently we do not support repeatable read and serializable isolation levels. With this PR BABEL repeatable read → PG repeatable read (if repeatable read escape hatch is set to pg_isolation) BABEL serializable → PG serializable (if serializable escape hatch is set to pg_isolation) REPEATABLE READ GUC:- 'repeatable_read_isolation' SERIALIZABLE GUC:- 'serializable_isolation' Issues Resolved: BABEL-4146 & BABEL-4145 Signed-off-by: Tanzeel Khan [email protected]
babelfish-for-postgresql · Oct 26, 2023 · 9fab304 · 9fab304
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diff --git a/contrib/babelfishpg_tsql/sql/sys_procedures.sql b/contrib/babelfishpg_tsql/sql/sys_procedures.sql
@@ -106,7 +106,8 @@ CREATE VIEW sys.babelfish_configurations_view as
     FROM pg_catalog.pg_settings 
     WHERE name collate "C" like 'babelfishpg_tsql.explain_%' OR
           name collate "C" like 'babelfishpg_tsql.escape_hatch_%' OR
-          name collate "C" = 'babelfishpg_tsql.enable_pg_hint';
+          name collate "C" = 'babelfishpg_tsql.enable_pg_hint' OR
+          name collate "C" like 'babelfishpg_tsql.isolation_level_%';
 GRANT SELECT on sys.babelfish_configurations_view TO PUBLIC;
 
 CREATE OR REPLACE PROCEDURE sys.sp_babelfish_configure(IN "@option_name" varchar(128),  IN "@option_value" varchar(128), IN "@option_scope" varchar(128))

diff --git a/contrib/babelfishpg_tsql/sql/upgrades/babelfishpg_tsql--3.3.0--3.4.0.sql b/contrib/babelfishpg_tsql/sql/upgrades/babelfishpg_tsql--3.3.0--3.4.0.sql
@@ -3096,6 +3096,16 @@ GRANT EXECUTE ON FUNCTION sys.FORMAT(IN anyelement, IN NVARCHAR, IN VARCHAR) TO
 -- Please have this be one of the last statements executed in this upgrade script.
 DROP PROCEDURE sys.babelfish_drop_deprecated_object(varchar, varchar, varchar);
 
+
+CREATE OR REPLACE VIEW sys.babelfish_configurations_view as
+    SELECT * 
+    FROM pg_catalog.pg_settings 
+    WHERE name collate "C" like 'babelfishpg_tsql.explain_%' OR
+          name collate "C" like 'babelfishpg_tsql.escape_hatch_%' OR
+          name collate "C" = 'babelfishpg_tsql.enable_pg_hint' OR
+          name collate "C" like 'babelfishpg_tsql.isolation_level_%';
+GRANT SELECT on sys.babelfish_configurations_view TO PUBLIC;
+
 -- After upgrade, always run analyze for all babelfish catalogs.
 CALL sys.analyze_babelfish_catalogs();
 

diff --git a/contrib/babelfishpg_tsql/src/backend_parser/gram-tsql-rule.y b/contrib/babelfishpg_tsql/src/backend_parser/gram-tsql-rule.y
@@ -4338,11 +4338,20 @@ tsql_IsolationLevelStr:
 				}
 			| REPEATABLE READ
 				{
-					TSQLInstrumentation(INSTR_UNSUPPORTED_TSQL_ISOLATION_LEVEL_REPEATABLE_READ);
-					ereport(ERROR,
+					if (pltsql_isolation_level_repeatable_read)
+					{
+						TSQLInstrumentation(INSTR_TSQL_ISOLATION_LEVEL_REPEATABLE_READ);
+						$$ = "repeatable read";	
+					}
+					else
+					{
+						TSQLInstrumentation(INSTR_UNSUPPORTED_TSQL_ISOLATION_LEVEL_REPEATABLE_READ);
+						ereport(ERROR,
 							(errcode(ERRCODE_SYNTAX_ERROR),
-							errmsg("REPEATABLE READ isolation level is not supported"),
+							errmsg("Isolation level ‘REPEATABLE READ’ is not currently supported in Babelfish. Please use ‘babelfishpg_tsql.isolation_level_repeatable_read’ config option to get PG repeatable read isolation level."),
 							parser_errposition(@1)));
+					}
+
 				}
 			| SNAPSHOT
 				{
@@ -4351,11 +4360,19 @@ tsql_IsolationLevelStr:
 				}
 			| SERIALIZABLE
 				{
-					TSQLInstrumentation(INSTR_UNSUPPORTED_TSQL_ISOLATION_LEVEL_SERIALIZABLE);
-					ereport(ERROR,
+					if (pltsql_isolation_level_serializable)
+					{
+						TSQLInstrumentation(INSTR_TSQL_ISOLATION_LEVEL_SERIALIZABLE);
+						$$ = "serializable";
+					}
+					else
+					{
+						TSQLInstrumentation(INSTR_UNSUPPORTED_TSQL_ISOLATION_LEVEL_SERIALIZABLE);
+						ereport(ERROR,
 							(errcode(ERRCODE_SYNTAX_ERROR),
-							errmsg("SERIALIZABLE isolation level is not supported"),
+							errmsg("Isolation level ‘SERIALIZABLE’ is not currently supported in Babelfish. Please use ‘babelfishpg_tsql.isolation_level_serializable’ config option to get PG serializable isolation level."),
 							parser_errposition(@1)));
+					}
 				}
 		;
 

diff --git a/contrib/babelfishpg_tsql/src/guc.c b/contrib/babelfishpg_tsql/src/guc.c
@@ -128,6 +128,12 @@ static const struct config_enum_entry escape_hatch_options[] = {
 	{NULL, EH_NULL, false},
 };
 
+static const struct config_enum_entry bbf_isolation_options[] = {
+	{"off", ISOLATION_OFF, false},
+	{"pg_isolation", PG_ISOLATION, false},
+	{NULL, ISOLATION_OFF, false},
+};
+
 static bool
 check_ansi_null_dflt_on(bool *newval, void **extra, GucSource source)
 {
@@ -1207,6 +1213,8 @@ int			escape_hatch_rowversion = EH_STRICT;
 int			escape_hatch_showplan_all = EH_STRICT;
 int			escape_hatch_checkpoint = EH_IGNORE;
 int			escape_hatch_set_transaction_isolation_level = EH_STRICT;
+int			pltsql_isolation_level_repeatable_read = ISOLATION_OFF;
+int 		pltsql_isolation_level_serializable = ISOLATION_OFF;
 
 void
 define_escape_hatch_variables(void)
@@ -1557,6 +1565,28 @@ define_escape_hatch_variables(void)
 							 PGC_USERSET,
 							 GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE | GUC_DISALLOW_IN_AUTO_FILE,
 							 NULL, NULL, NULL);
+
+	/* REPEATABLE READ MAPPING */
+	DefineCustomEnumVariable("babelfishpg_tsql.isolation_level_repeatable_read",
+							 gettext_noop("Select mapping for isolation level reapeatable read"),
+							 NULL,
+							 &pltsql_isolation_level_repeatable_read,
+							 ISOLATION_OFF,
+							 bbf_isolation_options,
+							 PGC_USERSET,
+							 GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE | GUC_DISALLOW_IN_AUTO_FILE,
+							 NULL, NULL, NULL);
+
+	/* SERIALIZABLE MAPPING */
+	DefineCustomEnumVariable("babelfishpg_tsql.isolation_level_serializable",
+							 gettext_noop("Select mapping for isolation level serializable"),
+							 NULL,
+							 &pltsql_isolation_level_serializable,
+							 ISOLATION_OFF,
+							 bbf_isolation_options,
+							 PGC_USERSET,
+							 GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE | GUC_DISALLOW_IN_AUTO_FILE,
+							 NULL, NULL, NULL);
 }
 
 void

diff --git a/contrib/babelfishpg_tsql/src/guc.h b/contrib/babelfishpg_tsql/src/guc.h
@@ -10,11 +10,18 @@ typedef enum EscapeHatchOption
 	EH_STRICT, EH_IGNORE, EH_NULL
 }			EscapeHatchOption;
 
+typedef enum IsolationOptions
+{
+	ISOLATION_OFF, PG_ISOLATION
+} IsolationOptions;
+
 extern bool pltsql_fmtonly;
 extern bool pltsql_enable_create_alter_view_from_pg;
 extern bool pltsql_enable_linked_servers;
 extern bool pltsql_allow_windows_login;
 extern char *pltsql_psql_logical_babelfish_db_name;
+extern int  pltsql_isolation_level_repeatable_read;
+extern int  pltsql_isolation_level_serializable;
 
 extern void define_custom_variables(void);
 extern void pltsql_validate_set_config_function(char *name, char *value);

diff --git a/contrib/babelfishpg_tsql/src/pltsql_instr.h b/contrib/babelfishpg_tsql/src/pltsql_instr.h
@@ -632,8 +632,10 @@ typedef enum PgTsqlInstrMetricType
 
 	INSTR_TSQL_ISOLATION_LEVEL_READ_UNCOMMITTED,
 	INSTR_TSQL_ISOLATION_LEVEL_READ_COMMITTED,
+	INSTR_TSQL_ISOLATION_LEVEL_REPEATABLE_READ,
 	INSTR_UNSUPPORTED_TSQL_ISOLATION_LEVEL_REPEATABLE_READ,
 	INSTR_TSQL_ISOLATION_LEVEL_SNAPSHOT,
+	INSTR_TSQL_ISOLATION_LEVEL_SERIALIZABLE,
 	INSTR_UNSUPPORTED_TSQL_ISOLATION_LEVEL_SERIALIZABLE,
 
 	INSTR_UNSUPPORTED_TSQL_SELECT_COL_ALIAS,

diff --git a/test/JDBC/expected/BABEL-3214.out b/test/JDBC/expected/BABEL-3214.out
@@ -44,7 +44,7 @@ SET TRANSACTION ISOLATION LEVEL REPEATABLE READ;
 GO
 ~~ERROR (Code: 33557097)~~
 
-~~ERROR (Message: REPEATABLE READ isolation level is not supported)~~
+~~ERROR (Message: Isolation level ‘REPEATABLE READ’ is not currently supported in Babelfish. Please use ‘babelfishpg_tsql.isolation_level_repeatable_read’ config option to get PG repeatable read isolation level.)~~
 
 SELECT CAST(current_setting('transaction_isolation') AS VARCHAR);
 SELECT transaction_isolation_level from sys.dm_exec_sessions WHERE session_id = @@SPID;
@@ -65,7 +65,7 @@ SET TRANSACTION ISOLATION LEVEL SERIALIZABLE;
 GO
 ~~ERROR (Code: 33557097)~~
 
-~~ERROR (Message: SERIALIZABLE isolation level is not supported)~~
+~~ERROR (Message: Isolation level ‘SERIALIZABLE’ is not currently supported in Babelfish. Please use ‘babelfishpg_tsql.isolation_level_serializable’ config option to get PG serializable isolation level.)~~
 
 SELECT CAST(current_setting('transaction_isolation') AS VARCHAR);
 SELECT transaction_isolation_level from sys.dm_exec_sessions WHERE session_id = @@SPID;
@@ -98,3 +98,92 @@ smallint
 5
 ~~END~~
 
+
+SELECT set_config('babelfishpg_tsql.isolation_level_repeatable_read','pg_isolation',false);
+SELECT set_config('babelfishpg_tsql.isolation_level_serializable','pg_isolation',false);
+SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED;
+SELECT CAST(current_setting('transaction_isolation') AS VARCHAR);
+SELECT transaction_isolation_level from sys.dm_exec_sessions WHERE session_id = @@SPID;
+GO
+~~START~~
+text
+pg_isolation
+~~END~~
+
+~~START~~
+text
+pg_isolation
+~~END~~
+
+~~START~~
+varchar
+read uncommitted
+~~END~~
+
+~~START~~
+smallint
+1
+~~END~~
+
+
+SET TRANSACTION ISOLATION LEVEL READ COMMITTED;
+SELECT CAST(current_setting('transaction_isolation') AS VARCHAR);
+SELECT transaction_isolation_level from sys.dm_exec_sessions WHERE session_id = @@SPID;
+GO
+~~START~~
+varchar
+read committed
+~~END~~
+
+~~START~~
+smallint
+2
+~~END~~
+
+
+SET TRANSACTION ISOLATION LEVEL REPEATABLE READ;
+GO
+SELECT CAST(current_setting('transaction_isolation') AS VARCHAR);
+SELECT transaction_isolation_level from sys.dm_exec_sessions WHERE session_id = @@SPID;
+GO
+~~START~~
+varchar
+repeatable read
+~~END~~
+
+~~START~~
+smallint
+5
+~~END~~
+
+
+SET TRANSACTION ISOLATION LEVEL SERIALIZABLE;
+GO
+SELECT CAST(current_setting('transaction_isolation') AS VARCHAR);
+SELECT transaction_isolation_level from sys.dm_exec_sessions WHERE session_id = @@SPID;
+GO
+~~START~~
+varchar
+serializable
+~~END~~
+
+~~START~~
+smallint
+4
+~~END~~
+
+
+SET TRANSACTION ISOLATION LEVEL SNAPSHOT;
+SELECT CAST(current_setting('transaction_isolation') AS VARCHAR);
+SELECT transaction_isolation_level from sys.dm_exec_sessions WHERE session_id = @@SPID;
+GO
+~~START~~
+varchar
+repeatable read
+~~END~~
+
+~~START~~
+smallint
+5
+~~END~~
+
diff --git a/test/JDBC/expected/BABEL-UNSUPPORTED.out b/test/JDBC/expected/BABEL-UNSUPPORTED.out
@@ -2035,6 +2035,8 @@ babelfishpg_tsql.explain_summary#!#on#!#Include summary information (e.g., total
 babelfishpg_tsql.explain_timing#!#on#!#Include actual startup time and time spent in each node in the output
 babelfishpg_tsql.explain_verbose#!#off#!#Display additional information regarding the plan
 babelfishpg_tsql.explain_wal#!#off#!#Include information on WAL record generation
+babelfishpg_tsql.isolation_level_repeatable_read#!#off#!#Select mapping for isolation level reapeatable read
+babelfishpg_tsql.isolation_level_serializable#!#off#!#Select mapping for isolation level serializable
 ~~END~~
 
 
@@ -2101,6 +2103,8 @@ babelfishpg_tsql.explain_summary#!#on#!#Include summary information (e.g., total
 babelfishpg_tsql.explain_timing#!#on#!#Include actual startup time and time spent in each node in the output
 babelfishpg_tsql.explain_verbose#!#off#!#Display additional information regarding the plan
 babelfishpg_tsql.explain_wal#!#off#!#Include information on WAL record generation
+babelfishpg_tsql.isolation_level_repeatable_read#!#off#!#Select mapping for isolation level reapeatable read
+babelfishpg_tsql.isolation_level_serializable#!#off#!#Select mapping for isolation level serializable
 ~~END~~
 
 
@@ -2148,6 +2152,8 @@ babelfishpg_tsql.explain_summary#!#on#!#Include summary information (e.g., total
 babelfishpg_tsql.explain_timing#!#on#!#Include actual startup time and time spent in each node in the output
 babelfishpg_tsql.explain_verbose#!#off#!#Display additional information regarding the plan
 babelfishpg_tsql.explain_wal#!#off#!#Include information on WAL record generation
+babelfishpg_tsql.isolation_level_repeatable_read#!#off#!#Select mapping for isolation level reapeatable read
+babelfishpg_tsql.isolation_level_serializable#!#off#!#Select mapping for isolation level serializable
 ~~END~~