Validate Query API

Validate Query Request

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); 

The index on which to run the request.

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); 

Build the desired query.

Set it to the request.

Optional arguments

The following arguments can optionally be provided:

request.explain(true); 

The explain parameter can be set to true to get more detailed information about why a query failed

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); 

Set the allShards parameter.

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); 

Set the rewrite parameter.

Synchronous Execution

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.

Asynchronous Execution

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 ValidateQueryRequest to execute and the ActionListener to use when the execution completes

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) {
            
        }
    };

Called when the execution is successfully completed.

Called when the whole ValidateQueryRequest fails.

Validate Query Response

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(); 
}

Check if the query is valid or not.

Get total number of shards.

Get number of shards that were successful.

Get number of shards that failed.

Get the shard failures as DefaultShardOperationFailedException.

Get the index of a failed shard.

Get the shard id of a failed shard.

Get the reason for shard failure.

Get the detailed explanation for the shards (if explain was set to true).

Get the index to which a particular explanation belongs.

Get the shard id to which a particular explanation belongs.

Get the actual explanation string.