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https://issues.apache.org/jira/browse/PHOENIX-3663?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15883451#comment-15883451
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James Taylor commented on PHOENIX-3663:
---------------------------------------
Patch looks good, [~gjacoby]. One minor issue:
- Instead of instantiating a SQLException directly, create a new enum in
SQLExceptionCode and use SQLExceptionInfo.Builder to create it:
{code}
@Override
public void addConnection(PhoenixConnection connection) throws
SQLException {
- connectionQueues.get(getQueueIndex(connection)).add(new
WeakReference<PhoenixConnection>(connection));
- if (returnSequenceValues) {
+ if (returnSequenceValues || shouldThrottleNumConnections) {
synchronized (connectionCountLock) {
+ if (shouldThrottleNumConnections && connectionCount + 1 >
maxConnectionsAllowed){
+ GLOBAL_PHOENIX_CONNECTIONS_THROTTLED_COUNTER.increment();
+ throw new SQLException(String.format("Could not create
connection " +
+ "because this client already has the maximum number" +
+ " of %d connections to the target cluster.",
maxConnectionsAllowed));
+ }
+
{code}
Something like this:
{code}
throw new
SQLExceptionInfo.Builder(SQLExceptionCode.MAX_CONNECTIONS_EXCEEDED)
.setMessage("Maximum connections = " + maxConnectionsAllowed)
.build().buildException();
{code}
That way it'll have a unique error code that clients can match against. You
could optionally create a new class derived from SQLException if we think it's
likely that clients might catch this exception. You'd then instantiate the
class in SQLExceptionCode (see other examples there).
> Implement resource controls in Phoenix JDBC driver
> --------------------------------------------------
>
> Key: PHOENIX-3663
> URL: https://issues.apache.org/jira/browse/PHOENIX-3663
> Project: Phoenix
> Issue Type: New Feature
> Affects Versions: 4.9.0
> Reporter: Geoffrey Jacoby
> Assignee: Geoffrey Jacoby
> Attachments: PHOENIX-3663.patch
>
>
> It would be very useful for service protection to be able to limit how many
> Phoenix connections a particular client machine can request at one time.
> This feature should be optional, and default to off for backwards
> compatibility.
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