Describe the bug

I'm exporting 280 MB database with Export to file with gzip compression.
Resulting file database.sql.gz has first 73 kB written in plain SQL and then the rest of file is gzip compressed.

To Reproduce

Steps to reproduce the behavior:

1. Export database to file with gzip compression checked.
2. Leave all other export settings default

Expected behavior

Resulting export file should be fully gzip compresed.

Server configuration

• Operating system: Debian 8
• Web server: nginx/1.6.2
• Database version: 8.0.13 - MySQL Community Server - GPL
• PHP version: 7.4.4
• phpMyAdmin version: 4.9.5

Client configuration

• Browser: Firefox
• Operating system: Win10