Index switching

A/B switching or Index switching is a great feature to ensure your indexes are available while doing a scratch index, this is a way to build an entirely new index and first swap when it is completed without any errors. This will reduce downtime of your webshop when you have to rebuild your index.

What index is active

Ucommerce is working on two indexes A or B, and will only read from one of them at a given time. The indication of the active version is different from provider to provider.

Lucene

In Lucene we have an extra file called A.active or B.active which can be found in the App_data folder ~/App_Data/Ucommerce/Indexes, if the index is not there try to scratch index.

Elastic Search

Elasticsearch implements A/B switching using Elasticsearch aliases. The search provider implementations use two aliases to tell one index role from the other: READ and WRITE. Full index alias is built as entity type name + index definition type name + unique hash + culture + alias name; e.g., an active index alias for the Products index using default scope will look like this: catalogsearchmodel-defaultcatalogsindexdefinition-b67ca44c-da-dk-read.