Github user paul-rogers commented on a diff in the pull request:
https://github.com/apache/drill/pull/960#discussion_r142579717
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/ExecConstants.java ---
@@ -351,7 +351,35 @@
MAX_QUERY_MEMORY_PER_NODE_KEY, 1024 * 1024, Long.MAX_VALUE);
/**
- * Minimum memory alocated to each buffered operator instance.
+ * Alternative way to compute per-query-per-node memory as a percent
+ * of the total available system memory.
+ * <p>
+ * Suggestion for computation.
+ * <ul>
+ * <li>Assume an allowance for non-managed operators. Default assumption:
+ * 50%</li>
+ * <li>Assume a desired number of concurrent queries. Default assumption:
+ * 10.</li>
+ * <li>The value of this parameter is<br>
+ * (1 - non-managed allowance) / concurrency</li>
--- End diff --
I thought about that. Then I remembered that we use ratios elsewhere such
as `planner.cpu_load_average`, `planner.affinity_factor`, and
`planner.memory.hash_agg_table_factor`. I didn't see any place we use the
percent-as-integer form.
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