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https://issues.apache.org/jira/browse/HBASE-16488?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16067623#comment-16067623
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Allan Yang commented on HBASE-16488:
------------------------------------
why do we need to wait here? shouldn't we throw a exception fast to tell the
caller the namespace manager is not ready? Otherwise, many calls like
createnamespace/modifynamespace from will suffer from a strange timeout.
{code}
void checkNamespaceManagerReady() throws IOException {
checkInitialized();
- if (tableNamespaceManager == null ||
- !tableNamespaceManager.isTableAvailableAndInitialized(true)) {
+ if (tableNamespaceManager == null) {
throw new IOException("Table Namespace Manager not ready yet, try again
later");
+ } else if (!tableNamespaceManager.isTableAvailableAndInitialized(true)) {
+ try {
+ // Wait some time.
+ long startTime = EnvironmentEdgeManager.currentTime();
+ int timeout = conf.getInt("hbase.master.namespace.wait.for.ready",
30000);
+ while (!tableNamespaceManager.isTableNamespaceManagerStarted() &&
+ EnvironmentEdgeManager.currentTime() - startTime < timeout) {
+ Thread.sleep(100);
+ }
+ } catch (InterruptedException e) {
+ throw (InterruptedIOException) new
InterruptedIOException().initCause(e);
+ }
+ if (!tableNamespaceManager.isTableNamespaceManagerStarted()) {
+ throw new IOException("Table Namespace Manager not fully initialized,
try again later");
+ }
}
}
{code}
> Starting namespace and quota services in master startup asynchronizely
> ----------------------------------------------------------------------
>
> Key: HBASE-16488
> URL: https://issues.apache.org/jira/browse/HBASE-16488
> Project: HBase
> Issue Type: Improvement
> Components: master
> Affects Versions: 2.0.0, 1.3.0, 1.0.3, 1.4.0, 1.1.5, 1.2.2
> Reporter: Stephen Yuan Jiang
> Assignee: Stephen Yuan Jiang
> Attachments: HBASE-16488.v1-branch-1.patch,
> HBASE-16488.v1-master.patch, HBASE-16488.v2-branch-1.patch,
> HBASE-16488.v2-branch-1.patch, HBASE-16488.v3-branch-1.patch,
> HBASE-16488.v3-branch-1.patch, HBASE-16488.v4-branch-1.patch,
> HBASE-16488.v5-branch-1.patch, HBASE-16488.v6-branch-1.patch,
> HBASE-16488.v7-branch-1.patch, HBASE-16488.v8-branch-1.patch
>
>
> From time to time, during internal IT test and from customer, we often see
> master initialization failed due to namespace table region takes long time to
> assign (eg. sometimes split log takes long time or hanging; or sometimes RS
> is temporarily not available; sometimes due to some unknown assignment
> issue). In the past, there was some proposal to improve this situation, eg.
> HBASE-13556 / HBASE-14190 (Assign system tables ahead of user region
> assignment) or HBASE-13557 (Special WAL handling for system tables) or
> HBASE-14623 (Implement dedicated WAL for system tables).
> This JIRA proposes another way to solve this master initialization fail
> issue: namespace service is only used by a handful operations (eg. create
> table / namespace DDL / get namespace API / some RS group DDL). Only quota
> manager depends on it and quota management is off by default. Therefore,
> namespace service is not really needed for master to be functional. So we
> could start namespace service asynchronizely without blocking master startup.
>
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