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https://issues.apache.org/jira/browse/HBASE-14623?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15292576#comment-15292576
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Yu Li commented on HBASE-14623:
-------------------------------
Bumping up the timeout may still not work under some corner case, say wal with
namespace data at the end of the split queue. And current implementation seems
to indicate namespace table is necessary to be online and will abort master if
wait timeout:
{code:title=TableNamespaceManager#start|borderStyle=solid}
try {
// Wait for the namespace table to be initialized.
long startTime = EnvironmentEdgeManager.currentTime();
int timeout = conf.getInt(NS_INIT_TIMEOUT, DEFAULT_NS_INIT_TIMEOUT);
while (!isTableAvailableAndInitialized()) {
if (EnvironmentEdgeManager.currentTime() - startTime + 100 > timeout) {
// We can't do anything if ns is not online.
throw new IOException("Timedout " + timeout + "ms waiting for
namespace table to "
+ "be assigned and enabled: " + getTableState());
}
Thread.sleep(100);
}
} catch (InterruptedException e) {
throw (InterruptedIOException) new InterruptedIOException().initCause(e);
}
{code}
> Implement dedicated WAL for system tables
> -----------------------------------------
>
> Key: HBASE-14623
> URL: https://issues.apache.org/jira/browse/HBASE-14623
> Project: HBase
> Issue Type: Sub-task
> Components: wal
> Reporter: Ted Yu
> Assignee: Ted Yu
> Labels: wal
> Fix For: 2.0.0
>
> Attachments: 14623-v1.txt, 14623-v2.txt, 14623-v2.txt, 14623-v2.txt,
> 14623-v2.txt, 14623-v3.txt, 14623-v4.txt
>
>
> As Stephen suggested in parent JIRA, dedicating separate WAL for system
> tables (other than hbase:meta) should be done in new JIRA.
> This task is to fulfill the system WAL separation.
> Below is summary of discussion:
> For system table to have its own WAL, we would recover system table faster
> (fast log split, fast log replay). It would probably benefit
> AssignmentManager on system table region assignment. At this time, the new
> AssignmentManager is not planned to change WAL. So the existence of this JIRA
> is good for overall system, not specific to AssignmentManager.
> There are 3 strategies for implementing system table WAL:
> 1. one WAL for all non-meta system tables
> 2. one WAL for each non-meta system table
> 3. one WAL for each region of non-meta system table
> Currently most system tables are one region table (only ACL table may become
> big). Choices 2 and 3 basically are the same.
> From implementation point of view, choices 2 and 3 are cleaner than choice 1
> (as we have already had 1 WAL for META table and we can reuse the logic).
> With choice 2 or 3, assignment manager performance should not be impacted and
> it would be easier for assignment manager to assign system table region (eg.
> without waiting for user table log split to complete for assigning system
> table region).
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