I think I tracked the problem down to Oxford Advanced Learner's Dictionary. When I move that into the dict directory look up times become untenable. Doesn't seem to matter whether it's enabled or not via the GUI in koreader.
What's crazy is the Oxford Advanced English directory is twice as large (200mb compressed) and doesn't seem to have slow lookup times.
Code:
Oxford_Advanced_Learner_s_Dictionary.dict.dz Oxford_Advanced_Learner_s_Dictionary.idx.oft res
[root@kindle stardict-Oxford_Advanced_Learner_s_Dictionary-2.4.2]# ls -lh
total 22048
-rwxrwxrwx 1 root root 3.8K Jul 29 2015 Oxford Advanced Learner's Dictionary.txt
-rwxrwxrwx 1 root root 18.7M May 18 2011 Oxford_Advanced_Learner_s_Dictionary.dict.dz
-rwxrwxrwx 1 root root 1.6M May 18 2011 Oxford_Advanced_Learner_s_Dictionary.idx
-rwxrwxrwx 1 root root 9.6K Jan 30 2019 Oxford_Advanced_Learner_s_Dictionary.idx.oft
-rwxrwxrwx 1 root root 164 May 18 2011 Oxford_Advanced_Learner_s_Dictionary.ifo
drwxrwxrwx 2 root root 1.2M Jan 30 2019 res
In other news, i'm *very* happy about nearly instantaneous dictionary lookups!!! This was always pestering me and now I have got it working great! Many thanks for everyone's help (and moreover, thank you for koreader which has made daily reading easier and more enjoyable)!
fun fact; i used to use the small 'quickview' version of dictionary lookup because it took so long that i could fling it around the page and keep reading and abandon it if i gave up waiting. no longer! i can enjoy the full screen for defintions. yay!
also multi page highlighting never worked that well for me before, but you've gone and fixed it with
https://github.com/koreader/koreader/pull/5984 .. i really have no idea how you can improve this app anymore but you folks keep finding ways!