Additional index to improve performance for agents getting tasks (#1238)

* added combined index for chunk

* updated changelog

Author: s3inlc

doc/changelog.md

@@ -3,6 +3,7 @@
 ## Enhancements
 
 - Added three more indexes in MySQL to improve the task view drastically (Note: these are not created on update due to performance issues, only on new installs)
+- Added an additional multi-column index in MySQL on the chunk table to increase performance for agents getting tasks (Note: these are not created on update due to performance issues, only on new installs)
 
 # v0.14.3 -> v0.14.4
 

src/install/hashtopolis.sql

@@ -1032,7 +1032,8 @@ ALTER TABLE `Chunk`
   ADD PRIMARY KEY (`chunkId`),
   ADD KEY `taskId` (`taskId`),
   ADD KEY `progress` (`progress`),
-  ADD KEY `agentId` (`agentId`);
+  ADD KEY `agentId` (`agentId`),
+  ADD KEY `idx_task_progress_length` (`taskId`, `progress`, `length`);
 
 ALTER TABLE `Config`
   ADD PRIMARY KEY (`configId`),