[
https://issues.apache.org/jira/browse/BOOKKEEPER-181?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13262223#comment-13262223
]
Matteo Merli commented on BOOKKEEPER-181:
-----------------------------------------
We've been going through the delete ledger operation
h4. Deletion sequence
# Client calls {{bookkeeperClient.deleteLedger(id)}}
## We know the {{N}} bookies that have this ledger {{(bk1, ..., bkn)}}
## Add {{id}} to the list of {{to_delete}} ledgers for {{bk1}}
## ...
## Add {{id}} to the list of {{to_delete}} ledgers for {{bkn}}
## Remove ledger {{id}} from main list (eg. '/ledgers/Lxxxxxx')
## Return success to the client
# Each bookie, in the GC thread will scan its own list of ledgers from the
{{to_delete}} queue and remove them from the list when the deletion has been
finalized.
h4. Handling failures
When the client deletes a ledger, it'd have to do {{N+1}} separated steps. Each
of them can potentially fail, and the client will receive an exception in this
case.
If the client receives an exception, it has to assume that the ledger has not
been deleted properly and retry the {{deleteLedger()}} call, although the
operation may have actually succeeded (or partially succeeded). In the
subsequent {{deleteLedger()}} call, the same steps will re-executed.
The worst-case scenario is that a bookie could see the same ledger more than
once in its own {{to_delete}} queue, and hence try to delete it twice, but this
should be easy to handle.
> Scale hedwig
> ------------
>
> Key: BOOKKEEPER-181
> URL: https://issues.apache.org/jira/browse/BOOKKEEPER-181
> Project: Bookkeeper
> Issue Type: Improvement
> Components: bookkeeper-server, hedwig-server
> Reporter: Sijie Guo
> Assignee: Sijie Guo
> Fix For: 4.2.0
>
> Attachments: hedwigscale.pdf, hedwigscale.pdf
>
>
> Current implementation of Hedwig and BookKeeper is designed to scale to
> hundreds of thousands of topics, but now we are looking at scaling them to
> tens to hundreds of millions of topics, using a scalable key/value store such
> as HBase.
--
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
