[SOLR-9493] uniqueKey generation fails if content POSTed as "application/javabin" and uniqueKey field comes as NULL (as opposed to not coming at all).

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Not A Problem
• Assignee: Unassigned
• Reporter: Yury Kartsev
• Created: 09/Sep/16 17:26
• Updated: 08/Jun/19 15:29
• Resolved: 30/Sep/16 19:10

Description

I have faced a weird issue when the same application code (using SolrJ) fails indexing a document without a unique key (should be auto-generated by SOLR) in SolrCloud and succeeds indexing it in standalone SOLR instance (or even in cloud mode, but from web interface of one of the replicas). Difference is obviously only between clients (CloudSolrClient vs HttpSolrClient) and SOLR URLs (Zokeeper hostname+port vs standalone SOLR instance hostname and port). Failure is seen as "org.apache.solr.client.solrj.SolrServerException: org.apache.solr.client.solrj.impl.HttpSolrClient$RemoteSolrException: Document is missing mandatory uniqueKey field: id".

I am using SOLR 5.1. In cloud mode I have 1 shard and 3 replicas.

After lot of debugging and investigation (see below as well as my StackOverflow post) I came to a conclusion that the difference in failing and succeeding calls is simply content type of the POSTing requests. Local proxy clearly shows that the request fails if content is sent as "application/javabin" (see attached screenshot with sensitive data removed) and succeeds if content sent as "application/xml; charset=UTF-8" (see attached screenshot with sensitive data removed).

Would you be able to please assist?

Thank you very much in advance!

------------------------
Copying whole description and investigation here as well:
------------------------

Documentation states:

Schema defaults and copyFields cannot be used to populate the uniqueKey field. You can use UUIDUpdateProcessorFactory to have uniqueKey values generated automatically.

Therefore I have added my uniqueKey field to the schema:

<fieldType name="uuid" class="solr.UUIDField" indexed="true" />
...
<field name="id" type="uuid" indexed="true" stored="true" required="true" />
...
<uniqueKey>id</uniqueKey>

Then I have added updateRequestProcessorChain to my solrconfig:

<updateRequestProcessorChain name="uuid">
    <processor class="solr.UUIDUpdateProcessorFactory">
        <str name="fieldName">id</str>
    </processor>
    <processor class="solr.RunUpdateProcessorFactory" />
</updateRequestProcessorChain>

And made it the default for the UpdateRequestHandler:

<initParams path="/update/**">
 <lst name="defaults">
  <str name="update.chain">uuid</str>
 </lst>
</initParams>

Adding new documents with null/absent id works fine as from web-interface of one of the replicas, as when using SOLR in standalone mode (non-cloud) from my application. Although when only I'm using SolrCloud and add document from my application (using CloudSolrClient from SolrJ) it fails with "org.apache.solr.client.solrj.SolrServerException: org.apache.solr.client.solrj.impl.HttpSolrClient$RemoteSolrException: Document is missing mandatory uniqueKey field: id"

All other operations like ping or search for documents work fine in either mode (standalone or cloud).

INVESTIGATION (i.e. more details):

In standalone mode obviously update request is:

POST standalone_host:port/solr/collection_name/update?wt=json

In SOLR cloud mode, when adding document from one replica's web interface, update request is (found through inspecting the call made by web interface):

POST replica_host:port/solr/collection_name_shard1_replica_1/update?wt=json

In both these cases payload is something like:

{
    "add": {
        "doc": {
                 .....
        },
        "boost": 1.0,
        "overwrite": true,
        "commitWithin": 1000
    }
}

In case when CloudSolrClient is used, the following happens (found through debugging):

Using ZK and some logic, URL list of replicas is constructed that looks like this:

[http://replica_1_host:port/solr/collection_name/,
 http://replica_2_host:port/solr/collection_name/,
 http://replica_3_host:port/solr/collection_name/]

This code is called:

LBHttpSolrClient.Req req = new LBHttpSolrClient.Req(request, theUrlList);
LBHttpSolrClient.Rsp rsp = lbClient.request(req);
return rsp.getResponse();

Where the second line fails with the exception.
If to debug the second line further, it ends up calling HttpClient.execute (from HttpSolrClient.executeMethod) for:

POST http://replica_1_host:port/solr/collection_name/update?wt=javabin&version=2 HTTP/1.1
POST http://replica_2_host:port/solr/collection_name/update?wt=javabin&version=2 HTTP/1.1
POST http://replica_3_host:port/solr/collection_name/update?wt=javabin&version=2 HTTP/1.1

And the very first request returns 400 Bad Request with replica 1 logging "Document is missing mandatory uniqueKey field: id" in the logs.

The funny thing is that when I execute the same request using POSTMAN (but with JSON instead of binary payload), it works! Am I doing something wrong here? I assume it's definitely something in the way of how the request is made...

UPDATE:

I have used local proxy in order to see the difference in these 2 requests sent by my application in order to understand what is different there. Looks like the only difference is content type. In case of cloud mode the payload for POSTing document is sent as "application/javabin" while in standalone mode it's sent as "application/xml; charset=UTF-8". Everything else is the same. First request results in 400 while second is 200.