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-rw-r--r--lib/stdlib/doc/src/ets.xml21
1 files changed, 16 insertions, 5 deletions
diff --git a/lib/stdlib/doc/src/ets.xml b/lib/stdlib/doc/src/ets.xml
index ad006f9a2b..57a19ef2ca 100644
--- a/lib/stdlib/doc/src/ets.xml
+++ b/lib/stdlib/doc/src/ets.xml
@@ -1135,11 +1135,22 @@ ets:select(Table, MatchSpec),</code>
Functions that makes such promises over many objects (like
<seealso marker="#insert/2"><c>insert/2</c></seealso>)
gain less (or nothing) from this option.</p>
- <p>Table type <c>ordered_set</c> is not affected by this option.
- Also, the memory consumption inflicted by
- both <c>write_concurrency</c> and <c>read_concurrency</c> is a
- constant overhead per table. This overhead can be especially
- large when both options are combined.</p>
+ <p>The memory consumption inflicted by both <c>write_concurrency</c>
+ and <c>read_concurrency</c> is a constant overhead per table for
+ <c>set</c>, <c>bag</c> and <c>duplicate_bag</c>. For
+ <c>ordered_set</c> the memory overhead depends on the number
+ of inserted objects and the amount of actual detected
+ concurrency. The memory overhead can be especially large when both
+ options are combined.</p>
+ <note>
+ <p>Prior to stdlib-3.7 (OTP-22.0) <c>write_concurrency</c> had no
+ effect on <c>ordered_set</c>.</p>
+ <p>The current implementation of <c>write_concurrency</c> for
+ <c>ordered_set</c> does only improve explicit single key
+ operations. Mixing single key operations with operations
+ potentially accessing multiple keys may even yield worse
+ performance with <c>write_concurrency</c> on <c>ordered_set</c>.</p>
+ </note>
<marker id="new_2_read_concurrency"></marker>
</item>
<tag><c>{read_concurrency,boolean()}</c></tag>