Magento re-indexes automatically whenever one or more items are changed (e.g. price changes, catalog or shopping cart price rules are created, new categories added, etc...). Reindexing is performed as a background process. Your store is accessible during all reindexing processes but may slow down if there are too many changes being made.
To avoid problems when multiple changes are being sent by the Celigo Magento connector that triggers automatic reindexing, set all indexers to run as cron jobs. Otherwise, every time changes to inventory, product data, price, and 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 by the connector.
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