Add support for GET.UNWATCH command

[JyotinderSingh]

GET.WATCH unsubscribes from a GET.WATCH subscription.

[nm123github]

Hey @JyotinderSingh, was planning to give this a try. Are GET.WATCH, GET.UNWATCH command's that can be called from the cli client? I get

127.0.0.1:7379> GET.WATCH k1
(error) ERR unknown command 'GET.WATCH', with args beginning with: k1

[JyotinderSingh]

Hey @JyotinderSingh, was planning to give this a try. Are GET.WATCH, GET.UNWATCH command's that can be called from the cli client? I get

127.0.0.1:7379> GET.WATCH k1

(error) ERR unknown command 'GET.WATCH', with args beginning with: k1

The CLI does not yet support these commands, however that should not stop you from being able to execute them (it only means that you wouldn't receive reactive updates from the server).
The reason why you're seeing this error is because you are not running the server in multithreaded mode.

[nm123github]

Yes, worked when i executed in multithreaded mode. Few questions,

• My understanding of GET.WATCH is that its similar to WATCH in redis. Meaning if we're watching a variable being used inside a transaction, and if any other connected client changed its value the transaction (for the first client) wont succeed. Is that a correct understanding?

• To test this, i was trying to use transactions in multithreaded mode. Noticed a segmentation fault when i tried to EXEC a transaction (only in multithreaded mode). Is this still work in progress?

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x100e3b39]

goroutine 11 [running]:
github.com/dicedb/dice/internal/eval.ExecuteCommand(0xc00048a5d0, 0x0, 0xc0000b2100, 0x0, 0x0)
	/Users/username/projects/dice/internal/eval/execute.go:51 +0x579
github.com/dicedb/dice/internal/shard.(*ShardThread).processRequest(0xc0000d61c0, 0xc0006bc340)
	/Users/username/projects/dice/internal/shard/shard_thread.go:92 +0x45

[JyotinderSingh]

Yes, worked when i executed in multithreaded mode. Few questions,

• My understanding of GET.WATCH is that its similar to WATCH in redis. Meaning if we're watching a variable being used inside a transaction, and if any other connected client changed its value the transaction (for the first client) wont succeed. Is that a correct understanding?

• To test this, i was trying to use transactions in multithreaded mode. Noticed a segmentation fault when i tried to EXEC a transaction (only in multithreaded mode). Is this still work in progress?

panic: runtime error: invalid memory address or nil pointer dereference

[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x100e3b39]



goroutine 11 [running]:

github.com/dicedb/dice/internal/eval.ExecuteCommand(0xc00048a5d0, 0x0, 0xc0000b2100, 0x0, 0x0)

	/Users/username/projects/dice/internal/eval/execute.go:51 +0x579

github.com/dicedb/dice/internal/shard.(*ShardThread).processRequest(0xc0000d61c0, 0xc0006bc340)

	/Users/username/projects/dice/internal/shard/shard_thread.go:92 +0x45

Transactions are not yet supported in multi threaded mode.

[psrvere]

@JyotinderSingh - please assign this to me.

[JyotinderSingh]

@JyotinderSingh - please assign this to me.

Done.

[psrvere]

Starting work on this from today.

[JyotinderSingh]

Starting work on this from today.

Awesome, thanks for the update!

[psrvere]

Raised PR