mariadb/mysql-test/suite/compat/oracle/t/vcol_innodb.test
Alexander Barkov 2b6d241ee4 MDEV-27744 LPAD in vcol created in ORACLE mode makes table corrupted in non-ORACLE
The crash happened with an indexed virtual column whose
value is evaluated using a function that has a different meaning
in sql_mode='' vs sql_mode=ORACLE:

- DECODE()
- LTRIM()
- RTRIM()
- LPAD()
- RPAD()
- REPLACE()
- SUBSTR()

For example:

CREATE TABLE t1 (
  b VARCHAR(1),
  g CHAR(1) GENERATED ALWAYS AS (SUBSTR(b,0,0)) VIRTUAL,
  KEY g(g)
);

So far we had replacement XXX_ORACLE() functions for all mentioned function,
e.g. SUBSTR_ORACLE() for SUBSTR(). So it was possible to correctly re-parse
SUBSTR_ORACLE() even in sql_mode=''.

But it was not possible to re-parse the MariaDB version of SUBSTR()
after switching to sql_mode=ORACLE. It was erroneously mis-interpreted
as SUBSTR_ORACLE().

As a result, this combination worked fine:

SET sql_mode=ORACLE;
CREATE TABLE t1 ... g CHAR(1) GENERATED ALWAYS AS (SUBSTR(b,0,0)) VIRTUAL, ...;
INSERT ...
FLUSH TABLES;
SET sql_mode='';
INSERT ...

But the other way around it crashed:

SET sql_mode='';
CREATE TABLE t1 ... g CHAR(1) GENERATED ALWAYS AS (SUBSTR(b,0,0)) VIRTUAL, ...;
INSERT ...
FLUSH TABLES;
SET sql_mode=ORACLE;
INSERT ...

At CREATE time, SUBSTR was instantiated as Item_func_substr and printed
in the FRM file as substr(). At re-open time with sql_mode=ORACLE, "substr()"
was erroneously instantiated as Item_func_substr_oracle.

Fix:

The fix proposes a symmetric solution. It provides a way to re-parse reliably
all sql_mode dependent functions to their original CREATE TABLE time meaning,
no matter what the open-time sql_mode is.

We take advantage of the same idea we previously used to resolve sql_mode
dependent data types.

Now all sql_mode dependent functions are printed by SHOW using a schema
qualifier when the current sql_mode differs from the function sql_mode:

SET sql_mode='';
CREATE TABLE t1 ... SUBSTR(a,b,c) ..;
SET sql_mode=ORACLE;
SHOW CREATE TABLE t1;   ->   mariadb_schema.substr(a,b,c)

SET sql_mode=ORACLE;
CREATE TABLE t2 ... SUBSTR(a,b,c) ..;
SET sql_mode='';
SHOW CREATE TABLE t1;   ->   oracle_schema.substr(a,b,c)

Old replacement names like substr_oracle() are still understood for
backward compatibility and used in FRM files (for downgrade compatibility),
but they are not printed by SHOW any more.
2023-11-08 15:01:20 +04:00

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--source include/have_innodb.inc
--echo #
--echo # MDEV-27744 LPAD in vcol created in ORACLE mode makes table corrupted in non-ORACLE
--echo #
FLUSH TABLES;
SET sql_mode='';
CREATE TABLE t (d INT,b VARCHAR(1),c CHAR(1),g CHAR(1) GENERATED ALWAYS AS (SUBSTR(b,0,0)) VIRTUAL,PRIMARY KEY(b),KEY g(g)) ENGINE=InnoDB;
--error ER_WRONG_VALUE_COUNT_ON_ROW
INSERT INTO t VALUES (0);
SET sql_mode='ORACLE';
INSERT INTO t SET c=REPEAT (1,0);
--error ER_BAD_FIELD_ERROR
ALTER TABLE t CHANGE COLUMN a b INT;
DELETE FROM t;
SET sql_mode='';
FLUSH TABLES;
INSERT INTO t SET c='0';
DROP TABLE t;
FLUSH TABLES;
SET sql_mode='';
CREATE TABLE t (a INT(1),d INT(1),b VARCHAR(1),c CHAR(1),vadc INT(1) GENERATED ALWAYS AS ( (a + length (d))) STORED,vbc CHAR(1) GENERATED ALWAYS AS (SUBSTR(b,0,0)) VIRTUAL,vbidxc CHAR(1) GENERATED ALWAYS AS (SUBSTR(b,0,0)) VIRTUAL,PRIMARY KEY(b (1),a,d),KEY d (d),KEY a (a),KEY c_renamed (c (1),b (1)),KEY b (b (1),c (1),a),KEY vbidxc (vbidxc),KEY a_2 (a,vbidxc),KEY vbidxc_2 (vbidxc,d)) DEFAULT CHARSET=latin1 ENGINE=InnoDB;
--error ER_WRONG_VALUE_COUNT_ON_ROW
INSERT INTO t VALUES (0,0,1,0,1,0,1,0,0);
SET SESSION sql_mode='ORACLE';
INSERT INTO t SET c=REPEAT (1,0);
--error ER_DUP_FIELDNAME
ALTER TABLE t CHANGE COLUMN a b CHAR(1);
DELETE FROM t;
SET SESSION sql_mode=DEFAULT;
DROP TABLE t;
SET sql_mode='';
CREATE TABLE t1 (d INT,b VARCHAR(1),c CHAR(1),g CHAR(1) GENERATED ALWAYS AS (SUBSTR(b,0,0)) VIRTUAL,PRIMARY KEY(b),KEY g(g)) ENGINE=InnoDB;
--error ER_WRONG_VALUE_COUNT_ON_ROW
INSERT INTO t1 VALUES (0);
SET sql_mode='ORACLE';
INSERT INTO t1 SET c=REPEAT (1,0);
--error ER_BAD_FIELD_ERROR
ALTER TABLE t1 CHANGE COLUMN a b INT;
DELETE FROM t1;
SET sql_mode='';
FLUSH TABLES;
INSERT INTO t1 SET c='0';
DROP TABLE t1;