Package com.google.cloud.bigtable.data.v2.models

Class Query

    • Method Detail

      • create

        public static Query create​(String tableId)
        Constructs a new Query object for the specified table id. The table id will be combined with the instance name specified in the BigtableDataSettings.

      • rowKey

        public Query rowKey​(String key)
        Adds a key to looked up

      • rowKey

        public Query rowKey​(com.google.protobuf.ByteString key)
        Adds a key to looked up

      • prefix

        public Query prefix​(com.google.protobuf.ByteString prefix)

      • range

        public Query range​(String start,
                   String end)
        Adds a range to be looked up.
        Parameters:
        start - The beginning of the range (inclusive). Can be null to represent negative infinity.
        end - The end of the range (exclusive). Can be null to represent positive infinity.

      • range

        public Query range​(com.google.protobuf.ByteString start,
                   com.google.protobuf.ByteString end)
        Adds a range to be looked up.
        Parameters:
        start - The beginning of the range (inclusive). Can be null to represent negative infinity.
        end - The end of the range (exclusive). Can be null to represent positive infinity.

      • limit

        public Query limit​(long limit)
        Limits the number of rows that can be returned

      • reversed

        public Query reversed​(boolean enable)
        Return rows in reverse order.

        The row will be streamed in reverse lexiographic order of the keys. The row key ranges are still expected to be oriented the same way as forwards. ie [a,c] where a <= c. The row content will remain unchanged from the ordering forward scans. This is particularly useful to get the last N records before a key: 

        
 query
   .range(ByteStringRange.unbounded().endOpen("key"))
   .limit(10)
   .reversed(true)

      • shard

        public List<Query> shard​(List<KeyOffset> sampledRowKeys)
        Split this query into multiple queries that can be evenly distributed across Bigtable nodes and be run in parallel. This method takes the results from BigtableDataClient.sampleRowKeysAsync(String) to divide this query into a set of disjoint queries that logically combine into form this query.

        Expected Usage: 

        
 List<KeyOffset> keyOffsets = dataClient.sampleRowKeysAsync("my-table").get();
 List<Query> queryShards = myQuery.shard(keyOffsets);
 List<ApiFuture<List<Row>>> futures = new ArrayList();
 for (Query subQuery : queryShards) {
   futures.add(dataClient.readRowsCallable().all().futureCall(subQuery));
 }
 List<List<Row>> results = ApiFutures.allAsList(futures).get();

      • shard

        public List<Query> shard​(SortedSet<com.google.protobuf.ByteString> splitPoints)
        Split this query into multiple queries that logically combine into this query. This is intended to be used by map reduce style frameworks like Beam to split a query across multiple workers.

        Expected Usage: 

        
 List<ByteString> splitPoints = ...;
 List<Query> queryShards = myQuery.shard(splitPoints);
 List<ApiFuture<List<Row>>> futures = new ArrayList();
 for (Query subQuery : queryShards) {
   futures.add(dataClient.readRowsCallable().all().futureCall(subQuery));
 }
 List<List<Row>> results = ApiFutures.allAsList(futures).get();

      • createPaginator

        @BetaApi("This surface is stable yet it might be removed in the future.")
public Query.QueryPaginator createPaginator​(int pageSize)
        Create a query paginator that'll split the query into smaller chunks.

        Example usage: 

        
 Query query = Query.create(...).range("a", "z");
 Query.QueryPaginator paginator = query.createQueryPaginator(100);
 ByteString lastSeenRowKey = ByteString.EMPTY;
 do {
     List<Row> rows = client.readRowsCallable().all().call(paginator.getNextQuery());
     for (Row row : rows) {
        // do some processing
        lastSeenRow = row;
     }
 } while (paginator.advance(lastSeenRowKey));

      • getBound

        public Range.ByteStringRange getBound()
        Get the minimal range that encloses all of the row keys and ranges in this Query.

      • toProto

        @InternalApi
public ReadRowsRequest toProto​(com.google.cloud.bigtable.data.v2.internal.RequestContext requestContext)
        Creates the request protobuf. This method is considered an internal implementation detail and not meant to be used by applications.

      • fromProto

        public static Query fromProto​(@Nonnull
                              ReadRowsRequest request)
        Wraps the protobuf ReadRowsRequest.

        WARNING: Please note that the project id & instance id in the table name will be overwritten by the configuration in the BigtableDataClient.

      • hashCode

        public int hashCode()
        Overrides:
        hashCode in class Object