Magento 2 : what is use of _replica table in Magento_Catalog module?

Question

As Magento releases 2.X version, I found _replica tables, particularly in the Magento_Catalog module may be for indexing the catalog data.

I also notice that _replica is nothing but the duplicate structure of the respective table in database nature but it means a lot for Magento 2 framework for read and write operational activities I guess.

I want to know that which operations Magento 2 application will consider for _replica tables for Magento_Catalog, CatalogRule and CatalogInventory module.

Thanks

Answer 1

Replica tables are mainly used for indexer optimization. Replica tables are used to prevent deadlocks or wait locks caused by read/write collisions on the same table.

In the above causes, Magento uses a separate table for reading and write operations and indexing. As a result of this switching process, customer can freely navigate to the category pages, search pages and user layered navigation pages filtered with price when you run full reindexing in the CLI.

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