The main culprits that slow down the import speed are:
- Huge data in CSV
- External images and URLs
- Bulky database
- Shared hosts
- Lack of resources
Huge data in CSV
Import speed depends on the amount of data present in the CSV including attributes, taxonomies, image URL, network speed, server, etc.
Make sure that only the necessary columns are mapped while importing.
External images and URLs
If the CSV contains images, the import seed depends on the time it takes to download the images. The time it takes to fetch external images and URLs will take longer than fetching images from the WP library.
Upload the image files to the WP media library and specify the image name in the CSV file.
During import, each CSV row and column import is accessing different tables in the database and entering data into each table. The import time will increase as the data needs to be written to each field in the database and continuous database hits can slow down the server.
Make sure the database and CSV don’t have any unwanted tables. If you find any, please try to remove them.
Not all servers are made equal. To keep costs down, many hosting providers will cram as many sites as possible into their hardware. They may also impose limits on the amount of PHP processing time or the number of SQL queries you can do. Additionally, they could limit your processing power. Or maybe they don’t do anything, but the 1,000 other websites running on the same machine are demanding so much CPU time that your import needs to compete for CPU time to finish processing.
Upgrading to a server with a faster CPU and disk is like renewing the engine in your truck. Sure, your move will be quicker, but that should not be the priority of your efforts.
Lack of server resources
Your import will be slowed if your server does not have adequate resources available. If you see that your server’s CPU or memory utilisation is reaching its limits during an import, upgrading to a more powerful server will help.
If your server’s available resources are running low, upgrading to a server with additional resources (RAM, CPUs, etc.) will help. This will help only if you are running out of resources. While the speed of your server’s CPU, RAM, and disk does affect how long your import takes, it’s not a major factor.