Is there any way to show progress on a gunzip < database.sql.gz | mysql ... process?
Monitor the progress of gunzip < database.sql.gz | mysql with pv (Pipe Viewer). If you haven't installed pv yet, you can do so using sudo apt-get install pv (Debian/Ubuntu based systems). The command should look like this:
Where pv acts as a magic eye, providing a real-time progress bar, speed of data transfer and Estimated Time of Arrival (ETA). Replace [user] and [database] with MySQL credentials.
Deep dive into pv
pv is more than just a progress bar—it's a powerful tool with a wide array of options. By using the rate-limit --rate-limit parameter, you can control the speed of data transfer. This can prevent situations where the system resource overflows because of your eagerness to get things done quickly. The joke goes: "What's a developer's favorite pick-up line? Can I overflow your buffer?"
Dealing with heavyweight databases
When dealing with a sizeable database, the progress bar and efficiency become even more critical. gunzip admirably handles decompression, but pv can enhance this process with its buffer size tuning option (--buffer-size).
Ingenious ways to estimate progress
If you prefer to go off the beaten path and need another way to monitor the progress, you can peek into your filesystem size with du -sh. This does not provide a direct progress bar, but it does offer useful insight for the savvy user.
Just make sure your database is droppable before running this command. You don't want to drop the database in the middle of an update, otherwise you'll play the role of the "drop table" meme in real life!
More ways to monitor and boost your process
Going beyond gunzip and pv, there are other tools out there like Mydumper/Myloader for parallel dumping and loading, which can significantly lower large database backup and restoration times.
Percona XtraBackup is suitable for hot backups of massive databases with a progress indicator. Lastly, custom scripts can offer a homebrewed progress bar using SQL COUNT queries inside shell script loops.
However, remember: With great progress bars come great responsibilities, aka the potential system overhead.
Maintaining data integrity
Ensuring data integrity is the key to any successful database operation. Validate the .gz file first with gunzip -t or a hash check, and run checksums after restoration to check for data consistency between the source and target. Schedule MySQL's FLUSH TABLES command to run periodically during the import process to safeguard against incomplete data issues.
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