[
https://issues.apache.org/jira/browse/HBASE-6269?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13401325#comment-13401325
]
ramkrishna.s.vasudevan commented on HBASE-6269:
-----------------------------------------------
@ShiXing
Yes, I agree that instead of getting the highest store file's scanner we get
the second highest. And since in this case comparing for '<0' should be fine i
feel.
Its better we fix this tho it may be very rare to get this problem.
> Lazyseek should use the maxSequenseId StoreFile's KeyValue as the latest
> KeyValue
> ---------------------------------------------------------------------------------
>
> Key: HBASE-6269
> URL: https://issues.apache.org/jira/browse/HBASE-6269
> Project: HBase
> Issue Type: Bug
> Components: regionserver
> Affects Versions: 0.94.0
> Reporter: ShiXing
> Assignee: ShiXing
> Attachments: HBASE-6269-v1.patch
>
>
> When I fix the bug HBASE-6195, there is happened to find sometimes the test
> case will fail, https://builds.apache.org/job/HBase-0.94/259/.
> If there are two Put/Increment with same row, family, qualifier, timestamp
> and different memstoreTS, after each Put/Increment, we do a memstore flush.
> So there will be two StoreFile with same KeyValue(except memstoreTS and
> SequenceId).
> When I got the row, I always got the old records, the test case like this:
> {code}
> public void testPutWithMemStoreFlush() throws Exception {
> Configuration conf = HBaseConfiguration.create();
> String method = "testPutWithMemStoreFlush";
> byte[] tableName = Bytes.toBytes(method);
> byte[] family = Bytes.toBytes("family");;
> byte[] qualifier = Bytes.toBytes("qualifier");
> byte[] row = Bytes.toBytes("putRow");
> byte[] value = null;
> this.region = initHRegion(tableName, method, conf, family);
> Put put = null;
> Get get = null;
> List<KeyValue> kvs = null;
> Result res = null;
>
> put = new Put(row);
> value = Bytes.toBytes("value0");
> put.add(family, qualifier, 1234567l, value);
> region.put(put);
> System.out.print("get value before flush after put value0 : ");
> get = new Get(row);
> get.addColumn(family, qualifier);
> get.setMaxVersions();
> res = this.region.get(get, null);
> kvs = res.getColumn(family, qualifier);
> for (int i = 0; i < kvs.size(); i++) {
> System.out.println(Bytes.toString(kvs.get(i).getValue()));
> }
> region.flushcache();
>
> System.out.print("get value after flush after put value0 : ");
> get = new Get(row);
> get.addColumn(family, qualifier);
> get.setMaxVersions();
> res = this.region.get(get, null);
> kvs = res.getColumn(family, qualifier);
> for (int i = 0; i < kvs.size(); i++) {
> System.out.println(Bytes.toString(kvs.get(i).getValue()));
> }
>
> put = new Put(row);
> value = Bytes.toBytes("value1");
> put.add(family, qualifier, 1234567l, value);
> region.put(put);
> System.out.print("get value before flush after put value1 : ");
> get = new Get(row);
> get.addColumn(family, qualifier);
> get.setMaxVersions();
> res = this.region.get(get, null);
> kvs = res.getColumn(family, qualifier);
> for (int i = 0; i < kvs.size(); i++) {
> System.out.println(Bytes.toString(kvs.get(i).getValue()));
> }
> region.flushcache();
> System.out.print("get value after flush after put value1 : ");
> get = new Get(row);
> get.addColumn(family, qualifier);
> get.setMaxVersions();
> res = this.region.get(get, null);
> kvs = res.getColumn(family, qualifier);
> for (int i = 0; i < kvs.size(); i++) {
> System.out.println(Bytes.toString(kvs.get(i).getValue()));
> }
>
> put = new Put(row);
> value = Bytes.toBytes("value2");
> put.add(family, qualifier, 1234567l, value);
> region.put(put);
> System.out.print("get value before flush after put value2 : ");
> get = new Get(row);
> get.addColumn(family, qualifier);
> get.setMaxVersions();
> res = this.region.get(get, null);
> kvs = res.getColumn(family, qualifier);
> for (int i = 0; i < kvs.size(); i++) {
> System.out.println(Bytes.toString(kvs.get(i).getValue()));
> }
> region.flushcache();
> System.out.print("get value after flush after put value2 : ");
> get = new Get(row);
> get.addColumn(family, qualifier);
> get.setMaxVersions();
> res = this.region.get(get, null);
> kvs = res.getColumn(family, qualifier);
> for (int i = 0; i < kvs.size(); i++) {
> System.out.println(Bytes.toString(kvs.get(i).getValue()));
> }
> }
> {code}
> and the result print as followed:
> {code}
> get value before flush after put value0 : value0
> get value after flush after put value0 : value0
> get value before flush after put value1 : value1
> get value after flush after put value1 : value0
> get value before flush after put value2 : value2
> get value after flush after put value2 : value0
> {code}
> I analyze the code for StoreFileScanner with lazy seek, the StoreFileScanners
> are sorted by SequenceId, so the latest StoreFile is on the top KeyValueHeap,
> and the KeyValue for latest StoreFile will comapre to the second latest
> StoreFile, but the second latest StoreFile generated the fake row for same
> row, family, qualifier excepts the timestamp( maximum), memstoreTS(0). And
> the latest KeyValue recognized as not latest than the second latest.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators:
https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira
