hcq/MaxScale
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Merge branch '2.1' into develop

Browse Source
This commit is contained in:
Johan Wikman
2017-08-14 10:36:34 +03:00
parent 9d3772a67e 7021041804
commit 4798810f76
11 changed files with 181 additions and 146 deletions
Download Patch File Download Diff File Expand all files Collapse all files

43
Documentation/About/Limitations.md
View File

@ -21,6 +21,35 @@ collect columns, functions and tables used in the `SELECT` defining the
Consequently, the database firewall will **not** block `WITH` statements
where the `SELECT` of the `WITH` clause refers to forbidden columns.
## Query Classification
Follow the [MXS-1350](https://jira.mariadb.org/browse/MXS-1350) Jira issue
to track the progress on this limitation.
XA transactions are not detected as transactions by MaxScale. This means
that all XA commands will be treated as unknown commands and will be
treated as operations that potentially modify the database (in the case of
readwritesplit, the statements are routed to the master).
MaxScale **will not** track the XA transaction state which means that any
SELECT queries done inside an XA transaction can be routed to servers that
are not part of the XA transaction.
This limitation can be avoided on the client side by disabling autocommit
before any XA transactions are done. The following example shows how a
simple XA transaction is done via MaxScale by disabling autocommit for the
duration of the XA transaction.
```
SET autocommit=0;
XA START 'MyXA';
INSERT INTO test.t1 VALUES(1);
XA END 'MyXA';
XA PREPARE 'MyXA';
XA COMMIT 'MyXA';
SET autocommit=1;
```
## Prepared Statements
For its proper functioning, MaxScale needs in general to be aware of the
@ -112,6 +141,14 @@ The avrorouter does not support the following data types and conversions:
The avrorouter does not do any crash recovery. This means that the avro files
need to be truncated to valid block lengths before starting the avrorouter.
#### Binlog Checksums
The avrorouter does not support binlog checksums. They must must not be used in
any of the binlogs that the avrorouter will process.
Follow [MXS-1341](https://jira.mariadb.org/browse/MXS-1341) for progress
on this issue.
### Limitations in the connection router (readconnroute)
If Master changes (ie. new Master promotion) during current connection, the
@ -164,12 +201,6 @@ this option for better performance.
For more information, read the
[ReadWriteSplit](../Routers/ReadWriteSplit.md) router documentation.
#### Parsing limitations
Galera Cluster variables, such as `@@wsrep_node_name`, are not resolved by the
embedded MariaDB parser. This usually means that the query will be routed to the
master.
#### Limitations in client session handling
Some of the queries that a client sends are routed to all backends instead of