[
https://issues.apache.org/jira/browse/ZOOKEEPER-1573?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13824644#comment-13824644
]
Raul Gutierrez Segales commented on ZOOKEEPER-1573:
---------------------------------------------------
Nit - maybe this:
{noformat}
+ * Snapshots are lazily created. So when the snapshot was in progress
+ * there is a chance that some of the later transactions can go into
+ * snapshot. While restoring same transactions NONODE/NODEEXISTS errors
+ * can come. Basically we can ignore all errors during the restore.
{noformat}
could be more clear like this:
{noformat}
+ * Snapshots are lazily created. So when a snapshot is in progress,
+ * there is a chance for later transactions to make to into the
snapshot.
+ * Then when the snapshot is restored, NONODE/NODEEXISTS errors
+ * could occur. It should be safe to ignore these.
{noformat}
Nit:
{noformat}
+ LOG.warn("Intrrupted");
{noformat}
typo.
Nit:
{noformat}
+ LOG.debug("Ignoring processTxn failure hdr: " + hdr.getType() + "
: error: " + rc.err + " path: " + rc.path);
{noformat}
use string extrapolation with {} instead of string concatenation.
Nit:
{noformat}
+ /**
+ * Test we can restore a snapshot that has delete txns ahead of the zxid
of the snapshot file. ZOOKEEPER-1573
+ */
{noformat}
make it:
{noformat}
+ /**
+ * ZOOKEEPER-1573: test restoring a snapshot with deleted txns ahead of
the snapshot file's zxid.
+ */
{noformat}
Nit:
{noformat}
+ LOG.info("Set lastProcessedZxid to " +
zks.getZKDatabase().getDataTreeLastProcessedZxid());
{noformat}
ditto wrt to string extrapolation via {}.
> Unable to load database due to missing parent node
> --------------------------------------------------
>
> Key: ZOOKEEPER-1573
> URL: https://issues.apache.org/jira/browse/ZOOKEEPER-1573
> Project: ZooKeeper
> Issue Type: Bug
> Components: server
> Affects Versions: 3.4.3, 3.5.0
> Reporter: Thawan Kooburat
> Attachments: ZOOKEEPER-1573.patch
>
>
> While replaying txnlog on data tree, the server has a code to detect missing
> parent node. This code block was last modified as part of ZOOKEEPER-1333. In
> our production, we found a case where this check is return false positive.
> The sequence of txns is as follows:
> zxid 1: create /prefix/a
> zxid 2: create /prefix/a/b
> zxid 3: delete /prefix/a/b
> zxid 4: delete /prefix/a
> The server start capturing snapshot at zxid 1. However, by the time it
> traversing the data tree down to /prefix, txn 4 is already applied and
> /prefix have no children.
> When the server restore from snapshot, it process txnlog starting from zxid
> 2. This txn generate missing parent error and the server refuse to start up.
> The same check allow me to discover bug in ZOOKEEPER-1551, but I don't know
> if we have any option beside removing this check to solve this issue.
--
This message was sent by Atlassian JIRA
(v6.1#6144)
