[
https://issues.apache.org/jira/browse/GORA-444?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16394565#comment-16394565
]
Carlos Muñoz edited comment on GORA-444 at 3/11/18 5:17 PM:
------------------------------------------------------------
Hi [~lewismc],
I have been playing with Apache Gora as a preparation for my GoSC application
in GORA-535 and I would like to tackle this issue because it is closely related
to backends development. This is what I found so far.
The implementation of a size() function in the Result API would be
straightforward in most of the backends because either they already have
internal size variables or they use lists/sets to store results. These backend
are:
|*Backend*|*Results list/size variable*|*Size() implementation*|
|[Aerospike|https://github.com/apache/gora/blob/master/gora-aerospike/src/main/java/org/apache/gora/aerospike/query/AerospikeQueryResult.java]|List<AerospikeResultRecord>
resultRecords;|resultRecords.size();|
|[Cassandra|https://github.com/apache/gora/blob/master/gora-cassandra/src/main/java/org/apache/gora/cassandra/query/CassandraResultSet.java]|int
size|size;|
|[CouchDB|https://github.com/apache/gora/blob/master/gora-couchdb/src/main/java/org/apache/gora/couchdb/query/CouchDBResult.java]|List<Map>
result;|result.size();|
|[DynamoDB|https://github.com/apache/gora/blob/master/gora-dynamodb/src/main/java/org/apache/gora/dynamodb/query/DynamoDBResult.java]|List<T>
dynamoDBResultSet;|dynamoDBResultSet.size();|
|[Infinispan|https://github.com/apache/gora/blob/master/gora-infinispan/src/main/java/org/apache/gora/infinispan/query/InfinispanResult.java]|List<T>
list;|size(); //already implemented|
|[JCache|https://github.com/apache/gora/blob/master/gora-jcache/src/main/java/org/apache/gora/jcache/query/JCacheResult.java]|NavigableSet<K>
cacheKeySet;|cacheKeySet.size();|
|[MongoDB|https://github.com/apache/gora/blob/master/gora-mongodb/src/main/java/org/apache/gora/mongodb/query/MongoDBResult.java]|int
size;|size;|
|[OrientDB|https://github.com/apache/gora/blob/master/gora-orientdb/src/main/java/org/apache/gora/orientdb/query/OrientDBResult.java]|int
size;|size;|
|[Solr|https://github.com/apache/gora/blob/master/gora-solr/src/main/java/org/apache/gora/solr/query/SolrResult.java]|SolrDocumentList
list;|list.size();|
|[Avro|https://github.com/apache/gora/blob/master/gora-core/src/main/java/org/apache/gora/avro/query/DataFileAvroResult.java]|long
start;
long end;|end-start;|
Other internal implementations:
|*Backend*|*Results list/size variable*|*Size() implementation*|
|[Mock|https://github.com/apache/gora/blob/master/gora-core/src/test/java/org/apache/gora/mock/store/MockDataStore.java]
*Test|…|return 0;|
|[Mem|https://github.com/apache/gora/blob/master/gora-core/src/main/java/org/apache/gora/memory/store/MemStore.java]|NavigableMap<K,
T> map;|return map.size();|
However, other backends rely on Scanners implementations which cannot provide
size()-like functions for performance reasons. These backends are:
|*Backend*|*Data*|
|[Accumulo|https://github.com/apache/gora/blob/master/gora-accumulo/src/main/java/org/apache/gora/accumulo/query/AccumuloResult.java]|RowIterator
iterator;|
|[HBase|https://github.com/apache/gora/blob/master/gora-hbase/src/main/java/org/apache/gora/hbase/query/HBaseGetResult.java]|Result
result;|
|[HBase|https://github.com/apache/gora/blob/master/gora-hbase/src/main/java/org/apache/gora/hbase/query/HBaseScannerResult.java]|ResultScanner
scanner;|
|[Avro|https://github.com/apache/gora/blob/master/gora-core/src/main/java/org/apache/gora/avro/query/AvroResult.java]|DatumReader<T>
reader;|
For thoses backends we could use one of the following strategies:
* Return a constant value such 0 or -1 (approach used by getProgress()
implementation).
* Throw an exception to indicate that the operation is not supported.
* Use a duplicated Scanner just for counting how many next() could be
performed (I know it is a very bad idea).
was (Author: carlosrmng):
Hi [~lewismc],
I have been playing with Apache Gora as a preparation for my GoSC application
in GORA-535 and I would like to tackle this issue because it is closely related
to backends development. This is what I found so far.
The implementation of a size() function in the Result API would be
straightforward in most of the backends because either they already have
internal size variables or they use lists/sets to store results. These backend
are:
|*Backend*|*Results list/size variable*|*Size() implementation*|
|[Aerospike|https://github.com/apache/gora/blob/master/gora-aerospike/src/main/java/org/apache/gora/aerospike/query/AerospikeQueryResult.java]|List<AerospikeResultRecord>
resultRecords;|resultRecords.size();|
|[Cassandra|https://github.com/apache/gora/blob/master/gora-cassandra/src/main/java/org/apache/gora/cassandra/query/CassandraResultSet.java]|int
size|size;|
|[CouchDB|https://github.com/apache/gora/blob/master/gora-couchdb/src/main/java/org/apache/gora/couchdb/query/CouchDBResult.java]|List<Map>
result;|result.size();|
|[DynamoDB|https://github.com/apache/gora/blob/master/gora-dynamodb/src/main/java/org/apache/gora/dynamodb/query/DynamoDBResult.java]|List<T>
dynamoDBResultSet;|dynamoDBResultSet.size();|
|[Infinispan|https://github.com/apache/gora/blob/master/gora-infinispan/src/main/java/org/apache/gora/infinispan/query/InfinispanResult.java]|List<T>
list;|size(); //already implemented|
|[JCache|https://github.com/apache/gora/blob/master/gora-jcache/src/main/java/org/apache/gora/jcache/query/JCacheResult.java]|NavigableSet<K>
cacheKeySet;|cacheKeySet.size();|
|[MongoDB|https://github.com/apache/gora/blob/master/gora-mongodb/src/main/java/org/apache/gora/mongodb/query/MongoDBResult.java]|int
size;|size;|
|[OrientDB|https://github.com/apache/gora/blob/master/gora-orientdb/src/main/java/org/apache/gora/orientdb/query/OrientDBResult.java]|int
size;|size;|
|[Solr|https://github.com/apache/gora/blob/master/gora-solr/src/main/java/org/apache/gora/solr/query/SolrResult.java]|SolrDocumentList
list;|list.size();|
|[Avro|https://github.com/apache/gora/blob/master/gora-core/src/main/java/org/apache/gora/avro/query/DataFileAvroResult.java]|long
start;
long end;|end-start;|
Other internal implementations:
|*Backend*|*Results list/size variable*|*Size implementation*|
|[Mock|https://github.com/apache/gora/blob/master/gora-core/src/test/java/org/apache/gora/mock/store/MockDataStore.java]
*Test|…|return 0;|
|[Mem|https://github.com/apache/gora/blob/master/gora-core/src/main/java/org/apache/gora/memory/store/MemStore.java]|NavigableMap<K,
T> map;|return map.size();|
However, other backends rely on Scanners implementations which cannot provide
size()-like functions for performance reasons. These backends are:
|*Backend*|*Data*|
|[Accumulo|https://github.com/apache/gora/blob/master/gora-accumulo/src/main/java/org/apache/gora/accumulo/query/AccumuloResult.java]|RowIterator
iterator;|
|[HBase|https://github.com/apache/gora/blob/master/gora-hbase/src/main/java/org/apache/gora/hbase/query/HBaseGetResult.java]|Result
result;|
|[HBase|https://github.com/apache/gora/blob/master/gora-hbase/src/main/java/org/apache/gora/hbase/query/HBaseScannerResult.java]|ResultScanner
scanner;|
|[Avro|https://github.com/apache/gora/blob/master/gora-core/src/main/java/org/apache/gora/avro/query/AvroResult.java]|DatumReader<T>
reader;|
For thoses backends we could use one of the following strategies:
* Return a constant value such 0 or -1 (approach used by getProgress()
implementation).
* Throw an exception to indicate that the operation is not supported.
* Use a duplicated Scanner just for counting how many next() could be
performed (I know it is a very bad idea).
> Add #size() to Result API
> -------------------------
>
> Key: GORA-444
> URL: https://issues.apache.org/jira/browse/GORA-444
> Project: Apache Gora
> Issue Type: New Feature
> Components: gora-core
> Reporter: Lewis John McGibbney
> Priority: Minor
> Fix For: 0.9
>
>
> Right now we iterate through results by doing
> {code}
> while (results.next()) {
> ...
> }
> {code}
> It is a pain to always require a counter of sorts and would be much more
> intuitive to provide a simple #size() method.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
