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https://issues.apache.org/jira/browse/DRILL-5716?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16195725#comment-16195725
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ASF GitHub Bot commented on DRILL-5716:
---------------------------------------
Github user arina-ielchiieva commented on a diff in the pull request:
https://github.com/apache/drill/pull/928#discussion_r143331950
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/work/foreman/rm/DistributedQueryQueue.java
---
@@ -165,12 +165,24 @@ public ConfigSet(SystemOptionManager optionManager) {
minimumOperatorMemory =
optionManager.getOption(ExecConstants.MIN_MEMORY_PER_BUFFERED_OP);
}
- @Override
- public boolean equals(Object other) {
- if (other == null || ! (other instanceof ConfigSet)) {
- return false;
- }
- ConfigSet otherSet = (ConfigSet) other;
+ /**
+ * Determine if this config set is the same as another one. Detects
+ * whether the configuration has changed between one sync point and
+ * another.
+ * <p>
+ * Note that we cannot use <tt>equals()</tt> here as, according to
+ * Drill practice, <tt>equals()</tt> is for use in collections and
+ * must be accompanied by a <tt>hashCode()</tt> method. Since this
+ * class will never be used in a collection, and does not need a
+ * hash function, we cannot use <tt>equals()</tt>.
+ *
+ * @param otherSet another snapshot taken at another time
+ * @return true if this configuration is the same as another
+ * (no update between the two snapshots), false if the config has
+ * changed between the snapshots
+ */
+
+ public boolean isSameAs(ConfigSet otherSet) {
--- End diff --
This is definitely a compromise :) Thanks for making the changes.
> Queue-based memory assignment for buffering operators
> -----------------------------------------------------
>
> Key: DRILL-5716
> URL: https://issues.apache.org/jira/browse/DRILL-5716
> Project: Apache Drill
> Issue Type: Improvement
> Affects Versions: 1.11.0
> Reporter: Paul Rogers
> Assignee: Paul Rogers
> Labels: doc-impacting
> Fix For: 1.12.0
>
>
> Apache Drill already has a queueing feature based on ZK semaphores. We did a
> bit of testing to show that the feature does, in fact work. We propose to
> enhance the feature with some light revisions to make work with the "managed"
> external sort and the newly-added spilling feature for the hash agg operator.
> The key requirement is to build on what we have for now; we may want to
> tackle a larger project to create a more complete solution later.
> Existing functionality:
> * Two ZK-based queues called the “small” and “large” query queues.
> * A threshold, call it T, given as a query cost, to determine the queue into
> which a query will go.
> * Admit levels for the two queues: call them Qs and Ql.
> Basically, when a query comes in:
> * Plan the query as usual.
> * Obtain the final query cost from the planner, call this C.
> * If C<T, the query goes into the small queue, else it goes into the large
> queue.
> * Suppose the small queue. Ask ZK if the query can run.
> * ZK checks if Qs queries are already running. If so, the query waits, else
> the query runs.
> The proposed changes include:
> * Refactor the code to provide a queueing API that supports a variety of
> queuing mechanisms.
> * Provide three: the null queue (default), an in-process queue (for testing)
> and the ZK queues.
> * Modify the query profile web UI to show two new bits of information about
> queues:
> - The queue to which the query was sent.
> - The total planning cost.
> * Modify the query profile web UI to show two memory assignment numbers:
> - Total memory allocated to the query
> - Memory per sort or hash-add operator
> Then, add to the queue mechanism the ability to do memory assignment:
> * Provide a weight, W: every small query gets 1 unit, every large query gets
> W units.
> * Use the queue admit levels to determine total units: U = Qs + W * Ql.
> * Obtain total direct memory from the system. M.
> * Subtract a reserve percent R for overhead.
> * Do the math to get the memory per query for each query:
> * For the small queue: (M - R) / U
> * For the large queue: (M - R) / U * W
> * Use this memory amount as the “memory per query” number in the existing
> sort/hash-agg memory assignment (instead of the fixed 2 GB.)
> The result will be a nice incremental addition to what we already have, and
> should make it a bit easier people to actually use the feature (because they
> can see the planning numbers and see the queues used, allowing them to
> effectively tune the system.)
> The API used for the above features also allow third parties to add on a more
> robust admission control feature as needed, perhaps tying into an existing
> queueing mechanism of their choice.
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