IMatch without Virus-Checker quicker?!

[sinus]

Hi,
I use usually "Avira Free Antivirus" as Virus-program.

Now, I have seen, randomly, that my virus-checker did NOT exclude the IMatch-DB.
I have read then in the manual, and the IMatch-manual says:

IMatch databases are pretty safe from being infected by computers virus. But you can never know, so better be safe.

A virus checker constantly scanning the database on every access will bring down the performance of IMatch to a crawl. You should exclude the folder containing the database from "on-access" virus checks for optimal performance. But let your virus checker scan the database folder at least once per day to be on the safe side.

So I did first add
- the database (x.imd5)
- the preview-files

And first impression, that IMatch is really faster, for example, if I change from Media and folders to Collections.

But here some questions arised for me:

- is it ok to add also the preview-files (as I did now)?
- what about the real files, makes it sense to exclude them also from virus-scanning?

And if I read the helpfile, it says, I should let scan the virus checker at least once a day.
- but since I cannot do such a configuration in my virus-scanner, I think, I must do this "manually" each day? (does "better" antivirus-program allow such a configuration, exclude a folder and do once each day a scan?)

Hm, I wonder, if I see more speed-enhancement from IMatch, now, because I have excluded the DB and previews. 

[Mario]

IMatch is constantly reading and writing from/to the database file. The database system creates short-lived temporary files during each transaction in the database folder. If you have  a virus checker which constantly scans these files on every read/write IMatch will be slow. Hence the suggestion in the help.

Preview cache files or your images should not be excluded. There is always the chance that some images are "prepared" to break software which processes JPEG files, in order to execute malicious code. But most virus checkers have an "on-write only" setting so your images and the preview cache files are only checked once, when they are created or updated. Not much performance loss there.

I find it more secure to scan my entire disks at least once a day / week - every single file. Most good virus checkers have this option  - even the built-in virus checker in Windows 10 (Defender) allows this when I'm not mistaken. I use two different anti-virus products (on my local machine and on the test/build machines) and they both have this option.