# Handy Script finding non-isbits fields
**URL:** https://discourse.julialang.org/t/handy-script-finding-non-isbits-fields/47402
**Category:** General Usage
**Tags:** performance
**Created:** [September 28, 2020, 12:20pm UTC](https://discourse.julialang.org/t/handy-script-finding-non-isbits-fields/47402 "2020-09-28T12:20:44Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@oxinabox](https://discourse.julialang.org/u/oxinabox)
#### Post date: [September 28, 2020, 12:20pm UTC](https://discourse.julialang.org/t/handy-script-finding-non-isbits-fields/47402/1 "2020-09-28T12:20:44Z")
For performance optimization it is useful for your types to be `isbits`.
But you can’t be `isbits` if you have any fields that are not.
I made a quick script for tracking them down
It turned out to need to be more complex than i thought so I am sharing it here
>
It should be fairly obvious that it is a bit of a hack, esp with how it handles Vectors and Dictionries,
but i think it is a hack that you could customize for your needs also
It’s outputs look something like:
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### Author:  [@Henrique\_Becker](https://discourse.julialang.org/u/Henrique_Becker)
#### Post date: [September 28, 2020, 1:59pm UTC](https://discourse.julialang.org/t/handy-script-finding-non-isbits-fields/47402/2 "2020-09-28T13:59:23Z")
There is some reason for you to delete the gist from the post message?
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### Author:  [@oxinabox](https://discourse.julialang.org/u/oxinabox)
#### Post date: [September 28, 2020, 2:24pm UTC](https://discourse.julialang.org/t/handy-script-finding-non-isbits-fields/47402/3 "2020-09-28T14:24:21Z")
oops. Fixed