Magento reindexes automatically whenever one or more items are changed (for example, price
changes, catalog or shopping cart price rules are created, new categories added, and so on).
Reindexing is performed as a background process; your store is accessible during all reindexing
To avoid problems when multiple Admin users update objects that trigger automatic
reindexing, set all indexers to run as cron jobs. Otherwise, every time an object is saved, any
affected objects with dependencies might cause a deadlock. Symptoms of a deadlock include
high CPU usage and MySQL errors. As a best practice, schedule indexing as a cron job to
prevent deadlocks from occurring.
The default mode for each indexer is specified in the system configuration. By default, indexers
that require manual updating are set to “Update on Save,” which means reindexing occurs after
a change is made from the Admin. The other option is to manually reindex every time a change
is made. (For example, if you change product attributes in the Admin, you must manually
update the Product Attributes index.) If you ever need to override the default index mode, you
can use the Action control.
Examples: Index Actions and Controls
To change the index mode:
1. On the Admin menu, select System > Index Management.
2. Select the checkbox of each indexer you want to change.
3. Set Actions to “Change Index Mode.” Then, set Index Mode to one of the following:
- Update on Save
- Manual Update
4. Click the Submit button to apply the change to each selected indexer.
Events that Trigger a Full Reindex
Full Reindex Triggers