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Posted to dev@gora.apache.org by "Alfonso Nishikawa (JIRA)" <ji...@apache.org> on 2017/07/17 18:09:00 UTC
[jira] [Updated] (GORA-514) Scan of a single key with a limit
clears the persistent instance when iterating results
[ https://issues.apache.org/jira/browse/GORA-514?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Alfonso Nishikawa updated GORA-514:
-----------------------------------
Attachment: GORA-514-Example-Test.diff
> Scan of a single key with a limit clears the persistent instance when iterating results
> ---------------------------------------------------------------------------------------
>
> Key: GORA-514
> URL: https://issues.apache.org/jira/browse/GORA-514
> Project: Apache Gora
> Issue Type: Bug
> Components: gora-accumulo, gora-cassandra, gora-core, gora-hbase, gora-jcache, gora-mongodb, gora-solr
> Affects Versions: 0.7, 0.8
> Reporter: Alfonso Nishikawa
> Priority: Minor
> Attachments: GORA-514-Example-Test.diff
>
>
> To put in context, I am just doing a scan where the start key, end key and limit are configurable:
> {code:java}
> Query<String,Persistent> dataQuery = dataStore.newQuery() ;
> if (startKey != null && !startKey.equals("")) {
> dataQuery.setStartKey(startKey);
> }
> if (endKey != null && !endKey.equals("")) {
> dataQuery.setEndKey(endKey);
> }
> dataQuery.setLimit(limit);
> Result<?,Persistent> result = dataQuery.execute();
>
> while (result.next()) {
> results.put(result.getKey(), result.get()) ;
> }
> {code}
> When the start key is equal to end key, and the limit is configured to a value >= (the default value is -1), the second call to result.next() in the while bucle clears the instance previously returned by result.get().
> We could think that this would be an expected behaviour since result.get() -especifically for HBase- is a reusable instance when performing a Get operation, but this clashes with the actual expected general behaviour in the usual Scan operation shown in the former code example.
> This is: next() and get() when performing a scan should behave the same no matter what initial/end keys you configure, and what maximum number of results you want.
> I implemented a test than shows the issue affecting Accumulo, Cassandra, HBase, JCache, MongoDB and Solr, probably because it is some issue in the core.
> To see the error, you can apply the attached patch with the tests example and execute:
> {code:sh}
> mvn -Dtest=#testScanSingleResultWithLimit -fn -DfailIfNoTests=false test
> {code}
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