Documentation: Add optimization note on message_attachment index addi…

…tion - refs BT#19984
chamilo · Jul 7, 2022 · f2bf937 · f2bf937
1 parent 4a31a7f
commit f2bf937
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/documentation/optimization.html b/documentation/optimization.html
@@ -256,6 +256,8 @@ <h2><a name="2.Slow-queries"></a>2. Slow queries</h2>
         ALTER TABLE c_chat_connected ADD INDEX idx_course_group(c_id, to_group_id);
         -- For big online exams, this index reduces the load considerably
         ALTER TABLE c_quiz_question ADD INDEX idx_cqq_cidid (c_id, id);
+        -- If you have many messages with attachments
+        ALTER TABLE message_attachment ADD index idx_msgat_msgid (message_id);
     </pre>
 <hr />
 <h2><a name="3.Indexes-caching"></a>3. Indexes caching</h2>