Validate Query API

A ValidateQueryRequest requires one or more indices on which the query is validated. If no index is provided the request is executed on all indices.

ValidateQueryRequest request = new ValidateQueryRequest(index); 

In addition it also needs the query that needs to be validated. The query can be built using the QueryBuilders utility class. The following code snippet builds a sample boolean query.

QueryBuilder builder = QueryBuilders
    .boolQuery() 
    .must(QueryBuilders.queryStringQuery("*:*"))
    .filter(QueryBuilders.termQuery("user", "kimchy"));
request.query(builder); 

The following arguments can optionally be provided:

request.explain(true); 

By default, the request is executed on a single shard only, which is randomly selected. The detailed explanation of the query may depend on which shard is being hit, and therefore may vary from one request to another. So, in case of query rewrite the allShards parameter should be used to get response from all available shards.

request.allShards(true); 

When the query is valid, the explanation defaults to the string representation of that query. With rewrite set to true, the explanation is more detailed showing the actual Lucene query that will be executed

request.rewrite(true); 

When executing a ValidateQueryRequest in the following manner, the client waits for the ValidateQueryResponse to be returned before continuing with code execution:

ValidateQueryResponse response = client.indices().validateQuery(request, RequestOptions.DEFAULT); 

Synchronous calls may throw an IOException in case of either failing to parse the REST response in the high-level REST client, the request times out or similar cases where there is no response coming back from the server.

In cases where the server returns a 4xx or 5xx error code, the high-level client tries to parse the response body error details instead and then throws a generic ElasticsearchException and adds the original ResponseException as a suppressed exception to it.

Executing a ValidateQueryRequest can also be done in an asynchronous fashion so that the client can return directly. Users need to specify how the response or potential failures will be handled by passing the request and a listener to the asynchronous indices-validate-query method:

client.indices().validateQueryAsync(request, RequestOptions.DEFAULT, listener); 

The asynchronous method does not block and returns immediately. Once it is completed the ActionListener is called back using the onResponse method if the execution successfully completed or using the onFailure method if it failed. Failure scenarios and expected exceptions are the same as in the synchronous execution case.

A typical listener for indices-validate-query looks like:

ActionListener<ValidateQueryResponse> listener =
    new ActionListener<ValidateQueryResponse>() {
        @Override
        public void onResponse(ValidateQueryResponse validateQueryResponse) {
            
        }

        @Override
        public void onFailure(Exception e) {
            
        }
    };

The returned ValidateQueryResponse allows to retrieve information about the executed operation as follows:

boolean isValid = response.isValid(); 
int totalShards = response.getTotalShards(); 
int successfulShards = response.getSuccessfulShards(); 
int failedShards = response.getFailedShards(); 
if (failedShards > 0) {
    for(DefaultShardOperationFailedException failure: response.getShardFailures()) { 
        String failedIndex = failure.index(); 
        int shardId = failure.shardId(); 
        String reason = failure.reason(); 
    }
}
for(QueryExplanation explanation: response.getQueryExplanation()) { 
    String explanationIndex = explanation.getIndex(); 
    int shardId = explanation.getShard(); 
    String explanationString = explanation.getExplanation(); 
}