For CHAR/VARCHAR/TEXT fields, the buffer size of a field represents
the field size in bytes, which can be bigger than the field size in
number of characters, for multi-byte character sets such as utf8,
utf8mb4 etc. The buffer also contains a byte length prefix which can be
up to 65532 bytes for a VARCHAR field, and much higher for a TEXT
field (we process a maximum byte length for a TEXT field which fits in
4 bytes, which is 2^32 - 1 = 4GB!).
There is also special processing for a TEXT field defined with a default
length like so:
CREATE TABLE cs1 (a TEXT CHARACTER SET utf8)
Here, the byte length is a fixed 65535, irrespective of the character
set used. This is different from a case such as:
CREATE TABLE cs1 (a TEXT(65535) CHARACTER SET utf8), where the byte length
for the field will be 65535*3.
The change for MCOL-4264 erroneously added the "lock_type" member
to cal_connection_info, which is shared between multiple tables.
So some tables that were opened for write erroneously identified
themselves as read only.
Moving the member to ha_mcs instead.
Problem:
When processing cross-engine queries like:
update cstab1 set a=100 where a not in (select a from innotab1 where a=11);
delete from innotab1 where a not in (select a from cstab1 where a=1);
the ColumnStore plugin erroneously executed the whole query inside
ColumnStore.
Fix:
- Adding a new member cal_connection_info::lock_type and setting it
inside ha_mcs_impl_external_lock() to the value passed in the parameter
"lock_type".
- Adding a method cal_connection_info::isReadOnly() to test
if the last table lock made in ha_mcs_impl_external_lock()
for done for reading.
- Adding a new condition checking cal_connection_info::isReadOnly() inside
ha_mcs_impl_rnd_init(). If the current table was locked last time for reading,
then doUpdateDelete() should not be executed.
For certain queries, such as:
update cs1 set i = 41 where i = 42 or (i is null and 42 is null);
the SELECT_LEX.where does not contain the required where conditions.
Server sends the where conditions in the call to cond_push(), so
we are storing them in a handler data member, condStack, and later
push them down to getSelectPlan() for UPDATES/DELETEs.
Original SH implementation sends the result set back to the client
thus it can't be used in INSERT..SELECT, SELECT INTO OUTFILE,CREATE
TABLE AS SELECT etc.
CLX-77 feature has been backported into MDB to enable SH to run
query part of the mentioned queries.
Direct update/delete executed doUpdateDelete as well as the regular
execution route for doUpdateDelete.
This patch only executes doUpdateDelete the first time and direct
update/delete collects the counts.
Disabled 4th if block in buildOuterJoin to handle non-optimized MDB query
structures.
Broke getSelectPlan into pieces: processFrom, processWhere.
MCOL-3593 UNION processing depends on two flags isUnion that comes as
arg of getSelectPlan and unionSel that is a local variable in
getSelectPlan. Modularization of getSelectPlan broke the mechanizm.
This patch is supposed to partially fix it.
MCOL-3593 Removed unused if condition from buildOuterJoin that allows
unsupported construct subquery in ON expression.
Fixed an improper if condition that ignors tableMap entries w/o condition
in external_lock thus external_lock doesn't clean up when the query
finishes.
Fixed wrong logging for queries processed in tableMode. Now rnd_init
properly sends queryText down to ExeMgr to be logged.
MCOL-3593 Unused attribute FromSubQuery::fFromSub was removed.
getSelectPlan has been modularized into: setExecutionParams,
processFrom, processWhere. SELECT, HAVING, GROUP BY, ORDER BY
still lives in getSelectPlan.
Copied optimization function simplify_joins_ into our pushdown
code to provide the plugin code with some rewrites from MDB it
expects.
The columnstore_processing_handlers_fallback session variable
has been removed thus CS can't fallback from SH to partial
execution paths, e.g. DH, GBH or plugin API.
MCOL-3602 Moved MDB optimizer rewrites into a separate file.
Add SELECT_LEX::optimize_unflattened_subqueries() call to fix IN
into EXISTS rewrite for semi-JOINs with subqueries.
disable_indices_for_CEJ() add index related hints to disable
index access methods in Cross Engine Joins.
create_SH() now flattens JOIN that has both physical tables and
views. This fixes most of views related tests in the regression.
This patch fixes:
MCOL-3557 - Row Based Replication events to ColumnStore tables will no
longer cause MariaDB to crash, it will error instead.
MCOL-3556 - Remove the Columnstore.xml variable to turn on ColumnStore
tables applying replication events and instead make it a system variable
that can be set in my.cnf called "columnstore_replication_slave". This
allows it to be set per-UM.
