FAQ
Add static readSnapshotsInfo to PersistentSnapshotDeletionPolicy
----------------------------------------------------------------

Key: LUCENE-2592
URL: https://issues.apache.org/jira/browse/LUCENE-2592
Project: Lucene - Java
Issue Type: Improvement
Components: Index
Reporter: Shai Erera
Assignee: Shai Erera
Priority: Minor
Fix For: 3.1, 4.0


PSDP persists the snapshots information in a Directory. When you open PSDP, it obtains a write lock on the snapshots dir (by keeping an open IndexWriter), and updates the directory when snapshots are created/released.

This causes problem in the following scenario -- you have two processes, one updates the 'content' index and keeps PSDP open (because it also takes snapshots). Another process wants to read the existing snapshots information and open a read-only IndexReader on the 'content' index. The other process cannot read the existing snapshots information, because p1 keeps a write lock on the snapshots directory.

There are two possible solutions:
# Have PSDP open the IndexWriter over the directory for each snapshot/release. A bit expensive, and unnecessary.
# Introduce a static readSnapshotsInfo on PSDP which accepts a Directory and returns the snapshots information. IMO it's cleaner, and won't have the performance overhead of opening/closing the IW as before.

I'll post a patch (implementing the 2nd approach) shortly. I'd appreciate any comments.

--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.


---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscribe@lucene.apache.org
For additional commands, e-mail: dev-help@lucene.apache.org

Search Discussions

  • Shai Erera (JIRA) at Aug 10, 2010 at 10:38 am
    [ https://issues.apache.org/jira/browse/LUCENE-2592?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

    Shai Erera updated LUCENE-2592:
    -------------------------------

    Attachment: LUCENE-2592.patch

    Patch adds readSnapshotsInfo as well as a test case.
    Add static readSnapshotsInfo to PersistentSnapshotDeletionPolicy
    ----------------------------------------------------------------

    Key: LUCENE-2592
    URL: https://issues.apache.org/jira/browse/LUCENE-2592
    Project: Lucene - Java
    Issue Type: Improvement
    Components: Index
    Reporter: Shai Erera
    Assignee: Shai Erera
    Priority: Minor
    Fix For: 3.1, 4.0

    Attachments: LUCENE-2592.patch


    PSDP persists the snapshots information in a Directory. When you open PSDP, it obtains a write lock on the snapshots dir (by keeping an open IndexWriter), and updates the directory when snapshots are created/released.
    This causes problem in the following scenario -- you have two processes, one updates the 'content' index and keeps PSDP open (because it also takes snapshots). Another process wants to read the existing snapshots information and open a read-only IndexReader on the 'content' index. The other process cannot read the existing snapshots information, because p1 keeps a write lock on the snapshots directory.
    There are two possible solutions:
    # Have PSDP open the IndexWriter over the directory for each snapshot/release. A bit expensive, and unnecessary.
    # Introduce a static readSnapshotsInfo on PSDP which accepts a Directory and returns the snapshots information. IMO it's cleaner, and won't have the performance overhead of opening/closing the IW as before.
    I'll post a patch (implementing the 2nd approach) shortly. I'd appreciate any comments.
    --
    This message is automatically generated by JIRA.
    -
    You can reply to this email to add a comment to the issue online.


    ---------------------------------------------------------------------
    To unsubscribe, e-mail: dev-unsubscribe@lucene.apache.org
    For additional commands, e-mail: dev-help@lucene.apache.org
  • Shai Erera (JIRA) at Aug 21, 2010 at 7:21 pm
    [ https://issues.apache.org/jira/browse/LUCENE-2592?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

    Shai Erera resolved LUCENE-2592.
    --------------------------------

    Resolution: Fixed

    Committed revision 987811 (3x).
    Committed revision 987814 (trunk).
    Add static readSnapshotsInfo to PersistentSnapshotDeletionPolicy
    ----------------------------------------------------------------

    Key: LUCENE-2592
    URL: https://issues.apache.org/jira/browse/LUCENE-2592
    Project: Lucene - Java
    Issue Type: Improvement
    Components: Index
    Reporter: Shai Erera
    Assignee: Shai Erera
    Priority: Minor
    Fix For: 3.1, 4.0

    Attachments: LUCENE-2592.patch


    PSDP persists the snapshots information in a Directory. When you open PSDP, it obtains a write lock on the snapshots dir (by keeping an open IndexWriter), and updates the directory when snapshots are created/released.
    This causes problem in the following scenario -- you have two processes, one updates the 'content' index and keeps PSDP open (because it also takes snapshots). Another process wants to read the existing snapshots information and open a read-only IndexReader on the 'content' index. The other process cannot read the existing snapshots information, because p1 keeps a write lock on the snapshots directory.
    There are two possible solutions:
    # Have PSDP open the IndexWriter over the directory for each snapshot/release. A bit expensive, and unnecessary.
    # Introduce a static readSnapshotsInfo on PSDP which accepts a Directory and returns the snapshots information. IMO it's cleaner, and won't have the performance overhead of opening/closing the IW as before.
    I'll post a patch (implementing the 2nd approach) shortly. I'd appreciate any comments.
    --
    This message is automatically generated by JIRA.
    -
    You can reply to this email to add a comment to the issue online.


    ---------------------------------------------------------------------
    To unsubscribe, e-mail: dev-unsubscribe@lucene.apache.org
    For additional commands, e-mail: dev-help@lucene.apache.org

Related Discussions

Discussion Navigation
viewthread | post
Discussion Overview
groupdev @
categorieslucene
postedAug 10, '10 at 10:34a
activeAug 21, '10 at 7:21p
posts3
users1
websitelucene.apache.org

1 user in discussion

Shai Erera (JIRA): 3 posts

People

Translate

site design / logo © 2021 Grokbase