[ https://issues.apache.org/jira/browse/HBASE-4485?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Amitanand Aiyer updated HBASE-4485: ----------------------------------- Attachment: 4485-v2.diff fix the issue using locks to ensure that Store.updateStoreFiles does not get called between StoreScanner getting the List of store files, and it getting to the MemStoreScanner. > Eliminate window of missing Data > -------------------------------- > > Key: HBASE-4485 > URL: https://issues.apache.org/jira/browse/HBASE-4485 > Project: HBase > Issue Type: Sub-task > Reporter: Amitanand Aiyer > Assignee: Amitanand Aiyer > Fix For: 0.94.0 > > Attachments: 4485-v1.diff, 4485-v2.diff, 4485-v3.diff, > repro_bug-4485.diff > > > After incorporating v11 of the 2856 fix, we discovered that we are still > having some ACID violations. > This time, however, the problem is not about including "newer" updates; but, > about missing older updates > that should be including. > Here is what seems to be happening. > There is a race condition in the StoreScanner.getScanners() > private List<KeyValueScanner> getScanners(Scan scan, > final NavigableSet<byte[]> columns) throws IOException { > // First the store file scanners > List<StoreFileScanner> sfScanners = StoreFileScanner > .getScannersForStoreFiles(store.getStorefiles(), cacheBlocks, > isGet, false); > List<KeyValueScanner> scanners = > new ArrayList<KeyValueScanner>(sfScanners.size()+1); > // include only those scan files which pass all filters > for (StoreFileScanner sfs : sfScanners) { > if (sfs.shouldSeek(scan, columns)) { > scanners.add(sfs); > } > } > // Then the memstore scanners > if (this.store.memstore.shouldSeek(scan)) { > scanners.addAll(this.store.memstore.getScanners()); > } > return scanners; > } > If for example there is a call to Store.updateStorefiles() that happens > between > the store.getStorefiles() and this.store.memstore.getScanners(); then > it is possible that there was a new HFile created, that is not seen by the > StoreScanner, and the data is not present in the Memstore.snapshot either. -- 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