refactor(exchange): Rename taskId to remoteTaskId

[lingbin]

Currently 'taskId' in an Exchange related class has two meanings, for
example ExchangeClient::taskId_ means local task (consumer),
ExchangeSource::taskId_ indicates a remote task (producer). This can
cause a bit of confusion.

And, in some places current codebase already uses 'remoteTaskId, such as
ExchangeClient::remoteTaskIds_. This patch renames the remaining
'task ID's representing the remote to 'remoteTaskId' to make it more
intuitive.

No functional changes.

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[lingbin]

@Yuhta Could you please take a look, thanks.

[facebook-github-bot]

@kevinwilfong has imported this pull request. If you are a Meta employee, you can view this diff on Phabricator.

[kevinwilfong]

@lingbin it looks like Presto is currently using the field taskId_ here https://github.com/prestodb/presto/blob/942cbbc7fb79e0ad04a1a164a6960eae91219a02/presto-native-execution/presto_cpp/main/PrestoExchangeSource.h#L146

Is there a way to do this in a backwards compatible way so that Presto isn't broken? E.g. since taskId_ is constant you could do this in 3 steps:

• land a change in Velox to add a remoteTaskId_ member alongside it initialized to the same value (ugly but temporary)
• land a change in Presto to start using remoteTaskId_ instead
• land a change in Velox to remove taskId_

[kgpai]

@lingbin Gentle reminder.

[lingbin]

Is there a way to do this in a backwards compatible way so that Presto isn't broken? E.g. since taskId_ is constant you could do this in 3 steps:

• land a change in Velox to add a remoteTaskId_ member alongside it initialized to the same value (ugly but temporary)
• land a change in Presto to start using remoteTaskId_ instead
• land a change in Velox to remove taskId_

@kevinwilfong Thanks very much. I have changed the code according to your suggestions. And I will continue to follow up and eventually remove the temporary 'taskId_'.

[lingbin]

@kevinwilfong Could you please help take a look again? cc @kgpai