[jira] [Commented] (BOOKKEEPER-3) Opening a ledger for reading causes an implicit close of ledger that is not deteced by write

["Flavio Junqueira (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/BOOKKEEPER-3?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13042098#comment-13042098 ] 

Flavio Junqueira commented on BOOKKEEPER-3:
-------------------------------------------

One option here is to have the writer client watching for the closed znode, and closing the ledger if the znode is created (a reader creates it while recovering the ledger, before actually reading).

> Opening a ledger for reading causes an implicit close of ledger that is not deteced by write 
> ---------------------------------------------------------------------------------------------
>
>                 Key: BOOKKEEPER-3
>                 URL: https://issues.apache.org/jira/browse/BOOKKEEPER-3
>             Project: Bookkeeper
>          Issue Type: Bug
>            Reporter: André Oriani
>
> Quoting the reply of Benjamin Reed to one of my emails
> {quote}
> there is one other bug you are seeing, before a ledger can be read, it must be closed. as your code shows, a process can open a ledger for reading while it is still being written to, which causes an implicit close that is not detected by the writer.
> {quote}
> Teste Case :
> {code}
> package br.unicamp.zooexp.booexp;
> import java.io.IOException;
> import java.util.Enumeration;
> import org.apache.bookkeeper.client.BKException;
> import org.apache.bookkeeper.client.BookKeeper;
> import org.apache.bookkeeper.client.LedgerEntry;
> import org.apache.bookkeeper.client.LedgerHandle;
> import org.apache.bookkeeper.client.BookKeeper.DigestType;
> import org.apache.zookeeper.KeeperException;
> public class BookTest {
>     public static void main (String ... args) throws IOException, InterruptedException, KeeperException, BKException{
>         BookKeeper bk = new BookKeeper("127.0.0.1");
>         LedgerHandle lh = bk.createLedger(DigestType.CRC32, "123".getBytes());
>         long lh_id = lh.getId();
>         lh.addEntry("Teste".getBytes());
>         lh.addEntry("Test2".getBytes());
>         System.out.printf("Got %d entries for lh\n",lh.getLastAddConfirmed()+1);
>         lh.addEntry("Test3".getBytes());
>         LedgerHandle lh1 = bk.openLedger(lh_id, DigestType.CRC32, "123".getBytes());
>         System.out.printf("Got %d entries for lh1\n",lh1.getLastAddConfirmed()+1);
>         lh.addEntry("Test4".getBytes());
>         lh.addEntry("Test5".getBytes());
>         lh.addEntry("Test6".getBytes());
>         System.out.printf("Got %d entries for lh\n",lh.getLastAddConfirmed()+1);
>         Enumeration<LedgerEntry> seq = lh.readEntries(0, lh.getLastAddConfirmed());
>         while (seq.hasMoreElements()){
>             System.out.println(new String(seq.nextElement().getEntry()));
>         }
>         lh.close();
>         lh1.addEntry("Test7".getBytes());
>         lh1.addEntry("Test8".getBytes());
>         System.out.printf("Got %d entries for lh1\n",lh1.getLastAddConfirmed()+1);
>         seq = lh1.readEntries(0, lh1.getLastAddConfirmed());
>         while (seq.hasMoreElements()){
>             System.out.println(new String(seq.nextElement().getEntry()));
>         }
>         lh1.close();
>         LedgerHandle lh2 = bk.openLedger(lh_id, DigestType.CRC32, "123".getBytes());
>         lh2.addEntry("Test9".getBytes());
>         System.out.printf("Got %d entries for lh2 \n",lh2.getLastAddConfirmed()+1);
>         seq = lh2.readEntries(0, lh2.getLastAddConfirmed());
>         while (seq.hasMoreElements()){
>             System.out.println(new String(seq.nextElement().getEntry()));
>         }
>         bk.halt();
>     }
> }
> {code}
> {panel:title=Output}
> Got 2 entries for lh
> Got 3 entries for lh1
> Got 6 entries for lh
> Teste
> Test2
> Test3
> Test4
> Test5
> Test6
> Got 3 entries for lh1
> Teste
> Test2
> Test3
> Got 3 entries for lh2 
> Teste
> Test2
> Test3
> {panel}

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