# Skipping the test temporarily when log-bin is enabled as the test contains a # statement accessing mysql.general_log in an trxn. The trxn status tracker # (@@session_track_transaction_info) marks it unsafe only when logbin is on --source include/not_log_bin.inc --echo # --echo # WL#6631: Detect transaction boundaries --echo # ############################################################################### # The main functionality implemented by WL#6631 is enhanced reporting # on transaction state. Historically, the server has already reported # with a flag whether we're inside a transaction, but on one hand, # BEGIN..COMMIT AND CHAIN..COMMIT AND CHAIN..COMMIT AND RELEASE would # look like a single very long transaction to users of that flag; on # the other, we could still re-locate the session elsewhere (e.g. load- # balance it) as long as no actual reads or writes have been done. # A client subscribing to WL#6631 reporting will see this more granular # state (implicit transaction, explicit transaction, work attached, etc.). # it may additionally subscribe to reporting on the characteristics of # the transaction (READ ONLY/READ WRITE; WITH CONSISTENT SNAPSHOT; # ISOLATION LEVEL) so it may restart the transaction elsewhere with the # same characteristics as the original transaction. # # We can switch a connection: # # a) if no transaction is active # # b) if a transaction is active, but has no "work" attached to it yet, # in which case we'll want to know its characteristics to move it: # # - was START TRANSACTION "WITH CONSISTENT SNAPSHOT" used? # # - was START TRANSACTION used with "READ ONLY" or "READ WRITE"? # (if neither was given in the statement, we won't flag either, # so the default will be used -- it's up to the client to # replicate that setting from SET TRANSACTION (i.e. GLOBAL and # SESSION transaction_isolation / transaction_read_only) as needed! # # - was "SET TRANSACTION ISOLATION LEVEL" one-shot set for this # transaction? # # - was "SET TRANSACTION READ [WRITE|ONLY]" one-shot used? # # # A transaction may be "explicit" (started with BEGIN WORK / # START TRANSACTION) or "implicit" (autocommit==0 && not in an # explicit transaction). A transaction of either type will end # when a statement causes an implicit or explicit commit. # In both cases, we'll see the union of any reads or writes # (transactional and non-transactional) that happened up to # that point in the transaction. # # In this test, we will document various state transitions between # no transaction, implicit transaction, and explict transaction active. # We will also show that "work attached" (read/write, transactional/ # non-transactional) as flagged as expected when a transaction is active. # Next, we will show that CHARACTERISTICS tracking supplies the correct # SQL statement or sequence of SQL statements to start a new transaction # with characteristics identital to that of the on-going transaction. # Finally, we'll explore some interesting situations -- reads within # a stored function, within LOCK, etc. --echo ######################################################################## --echo # --echo # set up: save settings --echo # SET autocommit=1; --echo # if we track CHARACTERISTICS, we must also track the tx_* sysvars! SELECT @@session.session_track_system_variables INTO @old_track_list; SET @track_list= CONCAT(@old_track_list, ",transaction_isolation, transaction_read_only"); SET SESSION session_track_system_variables=@track_list; SELECT @@session.session_track_state_change INTO @old_track_enable; SET SESSION session_track_state_change=TRUE; SELECT @@session.session_track_transaction_info INTO @old_track_tx; FLUSH STATUS; --echo ######################################################################## --echo # --echo # test "STATE" tracking: transaction type transitions --echo # SET SESSION session_track_transaction_info="STATE"; --enable_session_track_info --echo # 3.1.1.1.1 "explicit transaction active" # transition: no trx -> explicit trx START TRANSACTION; --echo # 3.1.1.1.1 ending explicit transaction explicitly # transition: explicit trx -> no trx COMMIT; --echo # 3.1.1.1.1 ending explicit transaction implicitly CREATE TABLE t1 (f1 INT) ENGINE="InnoDB"; START TRANSACTION; # DDL forcing an implicit commit (thereby ending the explicit transaction): # transition: explicit trx -> no trx DROP TABLE t1; --echo # 3.1.1.2 "no work attached" # no work attached after transaction started (unless WITH CONSISTENT SNAPSHOT) START TRANSACTION; # still no work attached as we do not access tables, and still in transaction: SET @dummy=0; ROLLBACK; --echo # 3.1.1.1.2 "implicit transaction active" --echo # # autocommit=0 enables implicit transactions # transition: no trx -> implicit trx SET autocommit=0; # DDL forcing an implicit commit # transition: implicit trx -> no trx CREATE TABLE t1 (f1 INT) ENGINE="InnoDB"; # attach a (transactional, since t1 is an InnoDB table) write: # transition: no trx -> implicit trx (with work) INSERT INTO t1 VALUES (1); # attach a transaction read; show that we get the union of the accesses so far: SELECT f1 FROM t1 LIMIT 1 INTO @dummy; # add a result-set: SELECT f1 FROM t1; # force commit by starting an explict transaction: # transition: implicit trx -> explicit trx BEGIN WORK; # end transaction by forcing an implicit commit: # transition: explicit trx -> no trx DROP TABLE t1; # start an implicit transaction SELECT RAND(22) INTO @dummy; # implicit transaction, explicit commit: # transition: implicit trx -> no trx COMMIT; # # SET TRANSACTION is OK during implicit transaction UNTIL tables are accessed CREATE TABLE t1 (f1 INT) ENGINE="InnoDB"; SET TRANSACTION READ ONLY; SET TRANSACTION READ WRITE; SELECT RAND(22) INTO @dummy; SET TRANSACTION READ WRITE; INSERT INTO t1 VALUES (1); --error ER_CANT_CHANGE_TX_CHARACTERISTICS SET TRANSACTION READ WRITE; DROP TABLE t1; # change back to autocommit mode. # Axiom: This should reset state as the implicit transaction, if any, ends. # transition: implicit trx -> no trx SET autocommit=1; --echo # read with and without result set: CREATE TABLE t1 (f1 INT) ENGINE="InnoDB"; CREATE TABLE t2 (f1 INT) ENGINE="InnoDB"; INSERT INTO t1 VALUES (123); BEGIN; # read + result set SELECT f1 FROM t1; COMMIT AND CHAIN; # read + write INSERT INTO t2 SELECT f1 FROM t1; COMMIT; DROP TABLE t1; DROP TABLE t2; --echo --echo ######################################################################## --echo # --echo # test "CHARACTERISTICS" tracking --echo # SET SESSION session_track_transaction_info="CHARACTERISTICS"; # side-effect: state will change to "explicit transaction active" START TRANSACTION; # side-effect: state -> "explicit transaction active" + "transactional read" START TRANSACTION WITH CONSISTENT SNAPSHOT; # side-effect: state -> "explicit transaction active" START TRANSACTION READ WRITE; --echo # state is again "we have an empty transaction", so make no state item START TRANSACTION READ ONLY; START TRANSACTION READ WRITE, WITH CONSISTENT SNAPSHOT; START TRANSACTION READ ONLY, WITH CONSISTENT SNAPSHOT; --echo # chain read chistics, but not snapshot: COMMIT AND CHAIN; # We can't set characteristics one-shots with an explicit transaction ongoing: --error ER_CANT_CHANGE_TX_CHARACTERISTICS SET TRANSACTION READ ONLY; --echo # will create an empty characteristics item by convention, plus 0 state ROLLBACK; --echo # Let's try the characteristics one-shots again, outside a transaction: --echo # chistics: READ ONLY SET TRANSACTION READ ONLY; --echo # chistics: READ ONLY + ISOL RR SET TRANSACTION ISOLATION LEVEL REPEATABLE READ; --echo # chistics: READ ONLY + ISOL RR SET TRANSACTION READ ONLY; --echo # chistics: READ WRITE + ISOL RR SET TRANSACTION READ WRITE; --echo # chistics: READ WRITE + ISOL RR SET TRANSACTION ISOLATION LEVEL REPEATABLE READ; --echo # chistics: READ ONLY + ISOL SER SET TRANSACTION READ ONLY, ISOLATION LEVEL SERIALIZABLE; --echo # chistics: READ ONLY + ISOL SER BEGIN WORK; COMMIT; --echo # Show how the characteristics one-shots interact with the session values: SET SESSION transaction_read_only=0; --echo # one-shot (different from session default) SET TRANSACTION READ ONLY; START TRANSACTION; COMMIT; --echo --echo # one-shot (repeats session default) SET TRANSACTION READ WRITE; START TRANSACTION; COMMIT; --echo --echo # session SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED; SET TRANSACTION ISOLATION LEVEL REPEATABLE READ; SET SESSION TRANSACTION ISOLATION LEVEL READ UNCOMMITTED; --echo # "isolation" one-shot is set, and added to chistics tracker (=> 1 item) SET TRANSACTION ISOLATION LEVEL READ COMMITTED; --echo # "read-only" one-shot is set, and added to chistics tracker (=> 2 items) SET TRANSACTION READ ONLY; --echo # setting the session default: --echo # - we receive "changed variable" for @@session.transaction_read_only --echo # - "read-only" one-shot is cleared, disappears from chistics tracker --echo # - "isolation" one-shot remains set, and remains in chistics tracker SET SESSION TRANSACTION READ ONLY; --echo # chistics: isolation level is READ COMMITTED (from one-shot), READ ONLY --echo # or READ WRITE not given, as we're using session default again START TRANSACTION; COMMIT; --echo --echo # chistics: READ ONLY SET TRANSACTION READ ONLY; --echo # chistics: READ ONLY, READ COMM SET TRANSACTION ISOLATION LEVEL READ COMMITTED; --echo # chistics: SESSION resets ISOL one-shot, READ ONLY remains SET SESSION TRANSACTION ISOLATION LEVEL READ UNCOMMITTED; --echo # chistics: SESSION resets READ one-shot, nothing remains SET SESSION TRANSACTION READ ONLY; --echo SET SESSION TRANSACTION ISOLATION LEVEL REPEATABLE READ; SET SESSION TRANSACTION READ WRITE; --echo --echo # show that START TRANSACTION READ ... overrides SET TRANSACTION READ .. SET TRANSACTION READ ONLY; START TRANSACTION READ WRITE; ROLLBACK; --echo --echo # chistics AND CHAIN # At this point, (COMMIT as well as ROLLBACK) AND CHAIN preserves chistics: SET TRANSACTION READ ONLY; START TRANSACTION; COMMIT AND CHAIN; ROLLBACK; --echo SET TRANSACTION ISOLATION LEVEL READ COMMITTED; START TRANSACTION READ ONLY; ROLLBACK AND CHAIN; COMMIT; --echo --echo # show that session_track_transaction_info="STATE" will hide some edges SET session_track_transaction_info="STATE"; --echo # normal syntax: TR->T->0 START TRANSACTION WITH CONSISTENT SNAPSHOT; COMMIT AND CHAIN; COMMIT; --echo # normal syntax: T->T->0 START TRANSACTION; --echo # state does not change, and therefore isn't reported COMMIT AND CHAIN; COMMIT; --echo # pathological syntax: TR->TR->0 START TRANSACTION WITH CONSISTENT SNAPSHOT; --echo # state does not change, and therefore isn't reported START TRANSACTION WITH CONSISTENT SNAPSHOT; COMMIT; --echo --echo # show that session_track_transaction_info="CHARACTERISTICS" shows more edges SET session_track_transaction_info="CHARACTERISTICS"; --echo # normal syntax: TR->T->0 START TRANSACTION WITH CONSISTENT SNAPSHOT; COMMIT AND CHAIN; COMMIT; --echo # normal syntax: T->T->0 START TRANSACTION; COMMIT AND CHAIN; COMMIT; --echo # pathological syntax: TR->TR->0 START TRANSACTION WITH CONSISTENT SNAPSHOT; START TRANSACTION WITH CONSISTENT SNAPSHOT; COMMIT; --echo --echo # chistics and interaction of implicit trx and explicit trx CREATE TABLE t1 (f1 INT) ENGINE="InnoDB"; SET autocommit=0; SET TRANSACTION READ ONLY; --error ER_CANT_EXECUTE_IN_READ_ONLY_TRANSACTION INSERT INTO t1 VALUES(1); ROLLBACK; SET TRANSACTION READ WRITE; # does not prevent further one-shots: SET TRANSACTION READ ONLY; SET TRANSACTION READ WRITE; INSERT INTO t1 VALUES(1); # in implicit transaction, can't set one-shots here using SET TRANSACTION --error ER_CANT_CHANGE_TX_CHARACTERISTICS SET TRANSACTION READ WRITE; # we can set one-shots using START TRANSACTION though, as that commits # an ongoing implicit transaction START TRANSACTION READ ONLY; # implicit COMMIT DROP TABLE t1; CREATE TABLE t1 (f1 INT) ENGINE="InnoDB"; SET TRANSACTION ISOLATION LEVEL SERIALIZABLE; # start implicit trx INSERT INTO t1 VALUES(1); --echo # implicit commit (chistics item here, clearing isolation level): ALTER TABLE t1 ADD COLUMN f2 INT; START TRANSACTION; ROLLBACK; --echo # start implicit trx INSERT INTO t1 VALUES(2,2); --echo # implicit commit (no chistics item here): ALTER TABLE t1 ADD COLUMN f3 INT; START TRANSACTION; ROLLBACK; DROP TABLE t1; SET autocommit=1; # cleanup SET session_track_transaction_info="STATE"; --echo --echo ######################################################################## --echo # --echo # show that table access reporting works in Stored Functions (SF) --echo # CREATE TABLE t1 (f1 INT) ENGINE="InnoDB"; INSERT INTO t1 VALUES (1); DELIMITER |; --echo # create func1() in system table: CREATE FUNCTION func1() RETURNS INTEGER BEGIN SET @dummy = 0; IF (SELECT * FROM t1) THEN SET @dummy = 1; END IF; RETURN @dummy; END| DELIMITER ;| --echo # func1() reads a trx table (and is read from a system table!): BEGIN; SELECT func1(); COMMIT; DROP TABLE t1; --echo # drop func1() from system table: DROP FUNCTION func1; --echo # --echo # log tables --echo # SET @old_log_output= @@global.log_output; SET @old_general_log= @@global.general_log; SET @old_general_log_file= @@global.general_log_file; TRUNCATE TABLE mysql.general_log; SET GLOBAL log_output = 'TABLE'; SET GLOBAL general_log= 'ON'; BEGIN; # Example query to be logged to the log table, general_log. # That table access does not become part of our state: SELECT 1 FROM DUAL; # Show that the above query was actually logged. # THIS (read) access will be flagged, as it's part of the user's transaction. SELECT " -> ", argument FROM mysql.general_log WHERE argument LIKE '% DUAL' AND (command_type!='Prepare'); ROLLBACK; TRUNCATE TABLE mysql.general_log; SET GLOBAL general_log_file= @old_general_log_file; SET GLOBAL general_log= @old_general_log; SET GLOBAL log_output= @old_log_output; --echo ######################################################################## --echo # --echo # XA --echo # CREATE TABLE t1 (f1 int) ENGINE="InnoDB"; SET SESSION session_track_transaction_info="CHARACTERISTICS"; --echo # XA ROLLBACK XA START 'test1'; INSERT t1 VALUES (1); XA END 'test1'; XA PREPARE 'test1'; XA ROLLBACK 'test1'; --echo # XA COMMIT XA START 'test2', 'yy'; INSERT t1 VALUES (2); XA END 'test2', 'yy'; XA PREPARE 'test2', 'yy'; XA COMMIT 'test2', 'yy'; --echo # XA COMMIT ONE PHASE XA START 'test3','xx',5; INSERT t1 VALUES (3); XA END 'test3','xx',5; XA COMMIT 'test3','xx',5 ONE PHASE; SET SESSION session_track_transaction_info="OFF"; DROP TABLE t1; --echo ######################################################################## --echo # --echo # cleanup --echo # --disable_session_track_info SET SESSION session_track_system_variables= @old_track_list; SET SESSION session_track_state_change=@old_track_enable; SET SESSION session_track_transaction_info=@old_track_tx; # ends