SearchQueries do not work on non-GCCCP clusters without waiting
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Charles Dixon June 3, 2020 at 6:50 AM
This behaviour is now that the SDK will "queue" (it doesn't actually queue, it creates a goroutine and spins it with a short (500 micros) sleep) any HTTP based requests (such as search) until the SDK has seen a cluster map from the server or the request times out. This makes usage in line with KV.
Documentation for gocb now has WaitUntilReady in every code example that shows opening a bucket or cluster also.
Matt Carabine May 18, 2020 at 12:52 PM
I've updated the workaround in my issue description too, to encourage its use rather than my hacky retry
Charles Dixon May 18, 2020 at 12:43 PM
I agree, I believe that it's on the roadmap to be documented. It's in a slightly weird place where it shouldn't be necessary once the fix is in place but is necessary at the moment. I will also add it as a known issue in the release notes including the above workaround.
Matt Carabine May 18, 2020 at 12:37 PM
I thought that would be the case, but I didn't know about the waitUntilReady method, that's much better than what I'd suggested.
Maybe would be good to get that included as part of our docs, given the default behavior of how the cluster object and connections are initialized?
Charles Dixon May 18, 2020 at 12:33 PM
Hi this is a known issue which I'm working on resolving to make feel like they behave in a similar way as KV operations. At the moment when a cluster or bucket is opened then we will attempt to asynchronously create connections to the node(s) in the connection string (note: connection time errors are no longer returned). KV operations are actually queued until the underlying connections are ready or the operation times out. The piece of work that I'm doing will make http based services also wait for connections or timeout.
The workaround for this for now (and it's possible that users may wish to continue to use this) is to use either `cluster.WaitUntilReady` or `bucket.WaitUntilReady`. These operations will currently wait for the underlying memcached connections to be ready for use or timeout. A future enhancement will also improve this to wait for specified services (such as fts) to be ready on the cluster.
Summary
SearchQuery (FTS) ops do not work in the 2.x Go SDK without sleeping for a while beforehand, if the cluster doesn't support GCCCP (i.e. is <6.5.0).
Steps to Reproduce
Create a single node 6.0.3 cluster running KV and Search.
Load the travel-sample bucket onto the cluster
Create an FTS index, the default (i.e. just click 'Create Index') is sufficient to demonstrate the issue
Run an FTS search from the Go SDK, ensuring to follow the advice in the documentation:
When using a Couchbase version < 6.5 you must create a valid Bucket connection using cluster.Bucket(name) before you can use Search.
I have attached an example self-contained reproduction case as
, and the logs as
.
Expected Results
The search results are returned successfully.
Actual Results
The application panics due to the following error:
Analysis
This seems to not work after opening a bucket, then immediately performing a search.
There are 2 ways to get this to work, one is to perform some KV ops on the default collection, which forces the connections to open.
The other is to sleep the calling goroutine for a bit (e.g. 5 seconds), if you sleep then the search works and you don't even need the default collection to be opened.
I've attached logs with the sleep as
to demonstrate the difference.
I suspect there's not appropriate handling within the SearchQuery code to wait for a cluster that's still initializing if the cluster does not support GCCCP.
Workaround
Wait until the bucket object is ready to have operations performed against it, this can be done using the Bucket.WaitUntilReady() API.
For example: