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https://issues.apache.org/jira/browse/HBASE-17678?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16040369#comment-16040369
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Zheng Hu commented on HBASE-17678:
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bq. Seems like a copy paste mistake. You should check prevFilterRCList for null.
[~anoop.hbase], Thanks for the careful check. Will upload an addendum for it.
bq. If cells are read from shared cache area, there is all chance that in btw
ship the cache area been evicted. So the cell will no longer be valid.
Got your point, currently , the cell is a ref to a slice in ByteBuff. So we'd
better to clone the cell into a new cell (only key is needed) and save it in
prevCellList ? For large row, the newly cloned cell will take more heap
memory, but it won't effect the ByteBuff GC.
> FilterList with MUST_PASS_ONE may lead to redundant cells returned
> ------------------------------------------------------------------
>
> Key: HBASE-17678
> URL: https://issues.apache.org/jira/browse/HBASE-17678
> Project: HBase
> Issue Type: Bug
> Components: Filters
> Affects Versions: 2.0.0, 1.3.0, 1.2.1
> Environment: RedHat 7.x
> Reporter: Jason Tokayer
> Assignee: Zheng Hu
> Attachments: HBASE-17678.v1.patch, HBASE-17678.v1.rough.patch,
> HBASE-17678.v2.patch, HBASE-17678.v3.patch, HBASE-17678.v4.patch,
> HBASE-17678.v4.patch, HBASE-17678.v5.patch, HBASE-17678.v6.patch,
> HBASE-17678.v7.patch, HBASE-17678.v7.patch,
> TestColumnPaginationFilterDemo.java
>
>
> When combining ColumnPaginationFilter with a single-element filterList,
> MUST_PASS_ONE and MUST_PASS_ALL give different results when there are
> multiple cells with the same timestamp. This is unexpected since there is
> only a single filter in the list, and I would believe that MUST_PASS_ALL and
> MUST_PASS_ONE should only affect the behavior of the joined filter and not
> the behavior of any one of the individual filters. If this is not a bug then
> it would be nice if the documentation is updated to explain this nuanced
> behavior.
> I know that there was a decision made in an earlier Hbase version to keep
> multiple cells with the same timestamp. This is generally fine but presents
> an issue when using the aforementioned filter combination.
> Steps to reproduce:
> In the shell create a table and insert some data:
> {code:none}
> create 'ns:tbl',{NAME => 'family',VERSIONS => 100}
> put 'ns:tbl','row','family:name','John',1000000000000
> put 'ns:tbl','row','family:name','Jane',1000000000000
> put 'ns:tbl','row','family:name','Gil',1000000000000
> put 'ns:tbl','row','family:name','Jane',1000000000000
> {code}
> Then, use a Scala client as:
> {code:none}
> import org.apache.hadoop.hbase.filter._
> import org.apache.hadoop.hbase.util.Bytes
> import org.apache.hadoop.hbase.client._
> import org.apache.hadoop.hbase.{CellUtil, HBaseConfiguration, TableName}
> import scala.collection.mutable._
> val config = HBaseConfiguration.create()
> config.set("hbase.zookeeper.quorum", "localhost")
> config.set("hbase.zookeeper.property.clientPort", "2181")
> val connection = ConnectionFactory.createConnection(config)
> val logicalOp = FilterList.Operator.MUST_PASS_ONE
> val limit = 1
> var resultsList = ListBuffer[String]()
> for (offset <- 0 to 20 by limit) {
> val table = connection.getTable(TableName.valueOf("ns:tbl"))
> val paginationFilter = new ColumnPaginationFilter(limit,offset)
> val filterList: FilterList = new FilterList(logicalOp,paginationFilter)
> println("@ filterList = "+filterList)
> val results = table.get(new
> Get(Bytes.toBytes("row")).setFilter(filterList))
> val cells = results.rawCells()
> if (cells != null) {
> for (cell <- cells) {
> val value = new String(CellUtil.cloneValue(cell))
> val qualifier = new String(CellUtil.cloneQualifier(cell))
> val family = new String(CellUtil.cloneFamily(cell))
> val result = "OFFSET = "+offset+":"+family + "," + qualifier
> + "," + value + "," + cell.getTimestamp()
> resultsList.append(result)
> }
> }
> }
> resultsList.foreach(println)
> {code}
> Here are the results for different limit and logicalOp settings:
> {code:none}
> Limit = 1 & logicalOp = MUST_PASS_ALL:
> scala> resultsList.foreach(println)
> OFFSET = 0:family,name,Jane,1000000000000
> Limit = 1 & logicalOp = MUST_PASS_ONE:
> scala> resultsList.foreach(println)
> OFFSET = 0:family,name,Jane,1000000000000
> OFFSET = 1:family,name,Gil,1000000000000
> OFFSET = 2:family,name,Jane,1000000000000
> OFFSET = 3:family,name,John,1000000000000
> Limit = 2 & logicalOp = MUST_PASS_ALL:
> scala> resultsList.foreach(println)
> OFFSET = 0:family,name,Jane,1000000000000
> Limit = 2 & logicalOp = MUST_PASS_ONE:
> scala> resultsList.foreach(println)
> OFFSET = 0:family,name,Jane,1000000000000
> OFFSET = 2:family,name,Jane,1000000000000
> {code}
> So, it seems that MUST_PASS_ALL gives the expected behavior, but
> MUST_PASS_ONE does not. Furthermore, MUST_PASS_ONE seems to give only a
> single (not-duplicated) within a page, but not across pages.
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