-
Most non-default MySQL DB System SQL modes.
For a list of supported SQL modes, see Section 2.11, “Supported SQL Modes”.
The
gb18030_chinese_ci
character set and collation.-
The
WITH ROLLUP
modifier inGROUP BY
clauses in the following cases:In queries that contain distinct aggregations.
In queries that contain duplicate
GROUP BY
keys.
COUNT(NULL)
in cases where it is used as an input argument for non-aggregate operators.-
UNION ALL
queries with anORDER BY
orLIMIT
clause, between different column types, between dictionary-encoded columns, or betweenENUM
columns.EXCEPT
,EXCEPT ALL
,INTERSECT
,INTERSECT ALL
, andUNION
queries with or without anORDER BY
orLIMIT
clause, between different column types, between dictionary-encoded columns, or betweenENUM
columns.EXCEPT
,EXCEPT ALL
,INTERSECT
,INTERSECT ALL
,UNION
andUNION ALL
subqueries with or without anORDER BY
orLIMIT
clause, between different column types, between dictionary-encoded columns, betweenENUM
columns, or specified in anIN
orEXISTS
clause. Comparison predicates,
GROUP BY
,JOIN
, and so on, if the key column isDOUBLE PRECISION
.-
Type conversion on relational data.
For example, the following query is not supported:
mysql> SELECT CONCAT(2, L_COMMENT) from LINEITEM;
-
Queries with an impossible
WHERE
condition (queries known to have an empty result set).For example, the following query is not offloaded:
mysql> SELECT AVG(c1) AS value FROM t1 WHERE c1 IS NULL;
-
Querying of
YEAR
type data using expressions and other functions.For example, the following queries are not offloaded:
mysql> SELECT YEAR(d) + 1 FROM t1; mysql> SELECT YEAR(d) + c1 FROM t1; # where c1 is an integer column
String operations involving columns with different collations.
Explicit partition selection. See Partition Selection.
Primary keys with column prefixes.
Virtual generated columns.
Queries that are executed as part of a trigger.
Queries that call a stored program.
Queries that are executed as part of a stored program.
Queries that are part of a multi-statement transaction.
-
Materialized views.
Only nonmaterialized views are supported. See Section 2.3.9, “Using Views”.
-
Partial query offload for regular
SELECT
queries.If all elements of the query are supported, the entire query is offloaded; otherwise, the query is executed on the MySQL DB System by default.
HeatWave supports
CREATE TABLE ... SELECT
andINSERT ... SELECT
statements where only theSELECT
portion of the operation is offloaded to HeatWave. See Section 2.3, “Running Queries”. -
SET timezone =
, with thetimezone
timezone
value specified as an offset from UTC in the form of[H]H:MM
and prefixed with a + or - is supported only by theUNIX_TIMESTAMP()
andFROM_UNIXTIME()
functions.Named time zones are not supported. For information about time zone offsets, see MySQL Server Time Zone Support.
-
Row widths in intermediate and final query results that exceed 4MB in size.
A query that exceeds this row width limit is not offloaded to HeatWave for processing.
-
Consecutive filter operations on derived tables.
For example, the following query is not supported:
mysql> SELECT * FROM (SELECT * FROM t1 WHERE x < 7) tt1, (SELECT * FROM t1 WHERE x < y) tt2 WHERE tt1.x > 5 AND tt1.x = tt2.x;
The query uses a filter for table
tt1
in the table scan of tablet1
(x < 7
) followed by a consecutive filter on tablett1
(tt1.x > 5
) in theWHERE
clause. Recursive common table expressions.
-
Operations involving
ALTER TABLE
such as loading, unloading, or recovering data when MySQL Server is running inSUPER_READ_ONLY
mode.MySQL Server is placed in
SUPER_READ_ONLY
mode when MySQL Server disk space drops below a set amount for a specific duration. For information about thresholds that control this behavior and how to disableSUPER_READ_ONLY
mode, refer to the Health Monitor documentation, in the MySQL HeatWave Service User Guide.