com.android.vending using much space. Is it normal?

[AC Question]

Hello, I wanna know if com.android.vending using much space (about 6.43 GB) is it normal? Cause my Android device only has 16 GB internal storage. And cut by the OS, so it's only has 11.3 GB space. From 11.3 space, 6.43 GB use by com.android.vending, 3.23 GB use by System data, so I only has free space 1.27 GB. I really wanna know, can I remove some/all files from "files" directory inside com.android.vending? So I could gain more space. When I check "files" directory inside com.android.vending, I found many files with number file name such as 1478654273365, 1474533050567, etc. Is it files which is use by system? Or is it a temporary or cache files? Almost forgot, I'm using android Kitkat 4.4.2.
Sorry about my poor English. And thanks for any kind of help.