The search index is kept in sync with CMS content whenever content is created, updated or deleted via the CMS. There are some situations such as direct MySQL database alterations and code changes that will mean the search index has to be repopulated.
When making changes the data or analyzers that are stored in the search index, you must re-index the content so all results and search operations are using the new data specification. Re-indexing is done via CLI commands, as they are potentially long running, high memory usage tasks.
elasticpress CLI command is used for all index management operations.
To re-sychronize the index for all sites
wp elasticpress index --network-wide
Re-sychronise the index and updating mappings (needed when updating synonym definitions)
wp elasticpress index --setup
When using CLI to perform re-indexes, it's recommended to set the
--posts-per-page argument to a figure around
200. By default, this figure is set to
350 which will often cause service timeouts. For example:
wp elasticpress index --posts-per-page 200
wp help elasticpress for all available CLI commands.