[olap mode] Add a construct to check if a connection has olap enabled #6171

brirams · 2020-05-11T19:42:34Z

Feature Description

Today, if you enable olap mode on a connection, there is no way to query vitess on that same connection to check if it's been enabled. It would be great to be able to do something along the lines of:

mysql> set workload='olap';
Query OK, 0 rows affected
Time: 0.003s
mysql> select @@workload;
+------------------------------------+
| @@workload                         |
|------------------------------------|
| olap                                                    |
+------------------------------------+

in order to avoid trying to set olap multiple times on the same connection and getting the following error:

mysql> set workload='olap';
Query OK, 0 rows affected
Time: 0.003s
mysql> set workload='olap';
ERROR 1105 (HY000): vtgate: $host:$port/: plan building not supported

Use Case(s)

multiplexing different types of queries to olap vs oltp connections based on the results of this check
not issuing more set queries than necessary

setassociative · 2020-05-11T20:49:15Z

Suggestion -- instead of supporting the ability to query the workload I think it'd be nicer if we could make set workload='olap' a supported/noop operation in olap mode.

The suggested approach means users will need to introduce an extra round trip that shouldn't strictly be necessary.

brirams · 2020-05-11T21:52:09Z

agreed -- i like that, too

demmer · 2020-05-11T23:37:55Z

Seems to me like we want both the ability to figure out the workload and also make the repeated set workload='olap' a no-op when already in olap mode, right?

harshit-gangal · 2020-11-04T19:47:35Z

mysql> select @@workload;
+-------------+
| @@workload  |
+-------------+
| UNSPECIFIED |
+-------------+
1 row in set (0.00 sec)

mysql> set workload = 'olap';
Query OK, 0 rows affected (0.00 sec)

mysql> select @@workload;
+------------+
| @@workload |
+------------+
| OLAP       |
+------------+
1 row in set (0.00 sec)

mysql> set workload = 'oltp';
Query OK, 0 rows affected (0.00 sec)

mysql> select @@workload;
+------------+
| @@workload |
+------------+
| OLTP       |
+------------+
1 row in set (0.00 sec)

Support is added looks like need to fix select @@workload when it is not set.
cc: @systay

harshit-gangal added Type: Bug Compontent: VTgate Good First Issue labels Nov 4, 2020

Oct	NOV	Dec
	10
2019	2020	2021

vitessio / vitess

[olap mode] Add a construct to check if a connection has olap enabled #6171

[olap mode] Add a construct to check if a connection has olap enabled #6171

brirams commented May 11, 2020 •

edited

setassociative commented May 11, 2020

brirams commented May 11, 2020

demmer commented May 11, 2020

harshit-gangal commented Nov 4, 2020

vitessio / vitess

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[olap mode] Add a construct to check if a connection has olap enabled #6171

[olap mode] Add a construct to check if a connection has olap enabled #6171

Comments

brirams commented May 11, 2020 • edited

Feature Description

Use Case(s)

setassociative commented May 11, 2020

brirams commented May 11, 2020

demmer commented May 11, 2020

harshit-gangal commented Nov 4, 2020

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brirams commented May 11, 2020 •

edited