. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 4 Fast vttablet state transitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111 7 Current state of monitoring 111 1. Vitess status pages . . . . . . . . . . . . . . . . . . . . . . . . . . . . instead will share the underlying connection between users. This means that it’s not safe to store any state in the session as you can’t be sure it will continue executing queries on the same connection, and

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 OnlineDDL & VTTablet state manager . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 Fast vttablet state transitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134 Current state of monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 Fast vttablet state transitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 Current state of monitoring 101 1. Vitess status pages . . . . . . . . . . . . . . . . . . . . . . . . . . . . instead will share the underlying connection between users. This means that it’s not safe to store any state in the session as you can’t be sure it will continue executing queries on the same connection, and

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 Fast vttablet state transitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 Current state of monitoring 91 1. Vitess status pages . . . . . . . . . . . . . . . . . . . . . . . . . . . . instead will share the underlying connection between users. This means that it’s not safe to store any state in the session as you can’t be sure it will continue executing queries on the same connection, and

instead will share the underlying connection between users. This means that it’s not safe to store any state in the session as you can’t be sure it will continue executing queries on the same connection, and used by other users later on. User-Defined Variables User defined variables are kept in the session state when working with MySQL. You can assign values to them using SET: SET @my_user_variable = 'foobar' SET query is not sent to MySQL. Instead, it is evaluated in the VTGate, and VTGate will keep this state for you. The second query is also not sent down. Trivial queries such as this one are actually fully

However, no calls to the topology service are made in the critical path of serving a query at steady state. That means queries are still served during temporary unavailability of topology. VSchema A VSchema (Error logs should only happen when the component is in bad shape, not because of bad transient state or bad user queries) • Does this change match our coding conventions / style? Linter was run and http://localhost:8001/api/v1/namespaces/default/services/vtgate-zone1:web/proxy/ Verify cluster You can check the state of your cluster with kubectl get pods,jobs. After a few minutes, it should show that all pods are

However, no calls to the topology service are made in the critical path of serving a query at steady state. That means queries are still served during temporary unavailability of topology. 13 VSchema A (Error logs should only happen when the component is in bad shape, not because of bad transient state or bad user queries) • Does this change match our coding conventions / style? Linter was run and http://localhost:8001/api/v1/namespaces/default/services/vtgate-zone1:web/proxy/ Verify cluster You can check the state of your cluster with kubectl get pods,jobs. After a few minutes, it should show that all pods are

However, no calls to the topology service are made in the critical path of serving a query at steady state. That means queries are still served during temporary unavailability of topology. 11 VSchema A (Error logs should only happen when the component is in bad shape, not because of bad transient state or bad user queries) • Does this change match our coding conventions / style? Linter was run and Vitess cluster with a single keyspace. Verify cluster Once successful, you should see the following state: $ kubectl get pods,jobs NAME READY STATUS RESTARTS AGE pod/commerce -apply-schema-initial -5twrs

{ "Cell": "", "Uid": 0 }, "Keyspace": "", "Shard": "", "Type": "idle", "State": "ReadOnly", "DbNameOverride": "", "KeyRange": { "Start": "", "End": "" } }