MaxScale 2.1 Support for MariaDB 10.2

MariaDB 10.2 introduces a fair amount of newfeatures.

In the following will be explained what impact some of those features have, when used together with MaxScale 2.1.

Window Functions

The parser of MariaDB MaxScale has not been extended with the window function syntax (the OVER keyword is not recognized) and hence statements using window functions will not be completely parsed.

Since the database firewall filter will block all statements that cannot be completely parsed, all statements that use window functions will be blocked, if the database firewall filter is used.

Otherwise the statements will be routed correctly.

SHOW CREATE USER

Cannot be completely parsed by the MaxScale parser and hence will be blocked by the database firewall filter, if it is used.

Otherwise the statements will be routed correctly.

CREATE USER

The new options are not parsed by the MaxScale parser and hence any statements using those will be blocked by the database firewall filter, if it is used.

Otherwise the statements will be routed correctly.

ALTER USER

The new options are not parsed by the MaxScale parser and hence any statements using those will be blocked by the database firewall filter, if it is used.

Otherwise the statements will be routed correctly.

WITH

The MaxScale parser correctly parses WITH statements such as

WITH t AS (SELECT a FROM t1 WHERE b >= 'c')
SELECT * FROM t2,t WHERE t2.c=t.a;

,

SELECT t1.a,t1.b FROM t1,t2
  WHERE t1.a>t2.c AND
        t2.c in (WITH t as (SELECT * FROM t1 WHERE t1.a<5)
                   SELECT t2.c FROM t2,t WHERE t2.c=t.a);

and

WITH engineers AS (
  SELECT * FROM employees WHERE dept IN ('Development','Support')
)
SELECT * FROM engineers E1
  WHERE NOT EXISTS (SELECT 1
    FROM engineers E2
    WHERE E2.country=E1.country
    AND E2.name <> E1.name);

.

However, the MaxScale parser fails to collect columns and table names from the SELECT of the WITH clause and consequently the database firewall filter will NOT be able to block WITH statements where the SELECT of the WITH clause refers to to forbidden columns.

CHECK CONSTRAINT

The new options are not parsed by the MaxScale parser and hence any statements using those will be blocked by the database firewall filter, if it is used.

Otherwise the statements will be routed correctly.

DEFAULT with expressions

Parsed and handled correctly.

EXECUTE IMMEDIATE

An EXECUTE IMMEDIATE statement will only be partially parsed, which means that such statements will be blocked by the database firewall filter, if it is used.

JSON functions

The MaxScape parser treats them as any other function.

However, as the parser is not aware of which JSON functions are strictlyread-only any statement using a JSON function will always be routed tomaster.

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