meta-accelerator

This helped me a lot.

This plugin can greatly speed up your wordpress by flattening your meta tables. I tested it on a WooCommerce installation with ~30,000 products with many meta for products. Before this plugin, the products listing in admin section took a lot of time to load, and individual product edit page was impossible to bring up. With this plugin, they come up quite fast after creating a flattened meta table for product post type. What it does is to take metas recorded for a post type and plant these metas into pre created flat tables. This makes reading/querying any post based on meta very easy. The plugin also hooks into proper filters for meta queries to take over meta querying. The plugin code is clean, neat, OOP and well crafted. Overall a great job. If developed, this plugin could help a lot of people. Actually, WordPress core should have included such functionality from the start.