> On Jan. 10, 2016, 12:32 a.m., Raju Bairishetti wrote: > > lens-driver-hive/src/main/java/org/apache/lens/driver/hive/HiveDriver.java, > > line 129 > > <https://reviews.apache.org/r/42067/diff/1/?file=1187330#file1187330line129> > > > > Can we create this map only if streaming result is enabled?
Better to create it eagerly. Otehrwise on each query that results in pre fetching we will have to do a syncronized null check and creation of map is required. > On Jan. 10, 2016, 12:32 a.m., Raju Bairishetti wrote: > > lens-server-api/src/main/java/org/apache/lens/server/api/driver/PartiallyFetchedInMemoryResultSet.java, > > line 74 > > <https://reviews.apache.org/r/42067/diff/1/?file=1187335#file1187335line74> > > > > remove trailing space Duplicate of Rajat's comment. > On Jan. 10, 2016, 12:32 a.m., Raju Bairishetti wrote: > > lens-server-api/src/main/java/org/apache/lens/server/api/driver/PartiallyFetchedInMemoryResultSet.java, > > line 87 > > <https://reviews.apache.org/r/42067/diff/1/?file=1187335#file1187335line87> > > > > spelling mistake here doNotPurge**Unitl**TimeMillis Fixed typo. > On Jan. 10, 2016, 12:32 a.m., Raju Bairishetti wrote: > > lens-server-api/src/main/java/org/apache/lens/server/api/driver/PartiallyFetchedInMemoryResultSet.java, > > line 109 > > <https://reviews.apache.org/r/42067/diff/1/?file=1187335#file1187335line109> > > > > Can we set this in while() loop itself? hasNext variable is not > > required if we set it in while() loop itself. > > > > ``` > > boolean isCompletelyFetched = true; > > while (inMemoryRS.hasNext()) { > > preFetchedRows.add(inMemoryRS.next()); > > numOfPreFetchedRows++; > > if (numOfPreFetchedRows >= reqPreFetchSize) { > > isCompletelyFetched = false; > > break; > > } > > } > > ``` The prosposed logic seems to break If the result has 5 rows and we are pre fetching 5. hasNext was needed to fetch an extra row. Sticking to current logic. > On Jan. 10, 2016, 12:32 a.m., Raju Bairishetti wrote: > > lens-server-api/src/main/java/org/apache/lens/server/api/driver/PartiallyFetchedInMemoryResultSet.java, > > line 123 > > <https://reviews.apache.org/r/42067/diff/1/?file=1187335#file1187335line123> > > > > Can we remove local variable & return directly? Fixed > On Jan. 10, 2016, 12:32 a.m., Raju Bairishetti wrote: > > lens-server/src/main/java/org/apache/lens/server/query/QueryExecutionServiceImpl.java, > > line 1961 > > <https://reviews.apache.org/r/42067/diff/1/?file=1187337#file1187337line1961> > > > > is type cast required? Yes. Accesing PartiallyFetchedInMemoryResultSet specific methods. - Puneet ----------------------------------------------------------- This is an automatically generated e-mail. To reply, visit: https://reviews.apache.org/r/42067/#review113446 ----------------------------------------------------------- On Jan. 8, 2016, 9:55 a.m., Puneet Gupta wrote: > > ----------------------------------------------------------- > This is an automatically generated e-mail. To reply, visit: > https://reviews.apache.org/r/42067/ > ----------------------------------------------------------- > > (Updated Jan. 8, 2016, 9:55 a.m.) > > > Review request for lens. > > > Repository: lens > > > Description > ------- > > LENS-901 support streaming results on lens > > > Diffs > ----- > > > lens-api/src/main/java/org/apache/lens/api/query/QueryHandleWithResultSet.java > a5da867 > lens-driver-hive/src/main/java/org/apache/lens/driver/hive/HiveDriver.java > 149c6ab > lens-driver-jdbc/src/main/java/org/apache/lens/driver/jdbc/JDBCDriver.java > 82d7513 > > lens-driver-jdbc/src/test/java/org/apache/lens/driver/jdbc/TestJdbcDriver.java > b96cf88 > > lens-server-api/src/main/java/org/apache/lens/server/api/LensConfConstants.java > 88e5a01 > > lens-server-api/src/main/java/org/apache/lens/server/api/driver/InMemoryResultSet.java > c64a3dd > > lens-server-api/src/main/java/org/apache/lens/server/api/driver/PartiallyFetchedInMemoryResultSet.java > PRE-CREATION > > lens-server-api/src/main/java/org/apache/lens/server/api/query/QueryContext.java > 1269e45 > > lens-server/src/main/java/org/apache/lens/server/query/QueryExecutionServiceImpl.java > 2dff9af > lens-server/src/main/resources/lenssession-default.xml 52e0cd0 > > lens-server/src/test/java/org/apache/lens/server/query/TestQueryService.java > c5d75de > > lens-server/src/test/java/org/apache/lens/server/query/TestResultFormatting.java > 30d1e34 > > Diff: https://reviews.apache.org/r/42067/diff/ > > > Testing > ------- > > Three properties have been added to enable streaming > > * lens.query.prefetch.inmemory.resultset > When set to true, specified number of rows of in-memory result set will be > pre-fetched > > * lens.query.prefetch.inmemory.resultset.rows > Specifies the number of rows to pre-fetch for in-memory result set when > lens.query.prefetch.inmemory.resultset is set to true. Default value is 100 > rows. > > * lens.query.prefetch.inmemory.resultset.ttl.millis Specifies the time in > milli seconds starting from query submission time for which the pre-fetched > in-memory result set will not be purged. This property is put to action only > when lens.query.prefetch.inmemory.resultset is set to true and all rows of > the in memory result set have been pre-fetched. The default value of this > property is 60 secs. > > Streaming(pre-fetched) result set is available in case the above proerties > are set and the result is a type of InMemoryResultSet. Further, the streming > is enabled only when all result rows have been prefetched.Partial Streaming > not supported as of now (Can be enabled in furtue is there is a clear use > case for it) > > Also note QueryHandleWithResultSet will now hold result metadta > (QueryResultSetMetadata) also. > This info will be useful for client in case the streaming results are > accesesd via execute_with_timeout API (REST End Point /queryapi/queries POST ) > > It is suggested to use this feature for queries that finish fast and return > small number of rows. Streaming and persistence by server can happen > parallely for streamed result sets. > > Will add more details on **Testing** done . Was able to build and run > checkstyle. Also ran the added test cases for this feature. > > **TODO** PartiallyFetchedInMemoryResultSet can override > InMemoryResultSet.toQueryResult() and optimize the case where result has been > completely fetched already. > > > Thanks, > > Puneet Gupta > >
