Indexing settings - PHP / Web server

'Timeout script':

In this field, you can optionally enter the time interval in seconds at which the search indexing should be restarted. This should be below the provider's timeout value for PHP scripts.
If a page is indexed within this time, the timeout starts again.

'Reload after':

In this field, you can optionally enter the number of pages after which a reload of the indexing run is forced. If a timeout is reached beforehand, the system continues with the next page.

'Memory Limit (MB)':

In this field, you can optionally enter the memory limit to be used until the next reload of an indexing run. If certain documents are not indexed, this may be because the memory limit has been set too low. If no value is entered, the default value from the PHP configuration is assumed.

Please note:
"Timeout Script" and "Reload after" work together. Both are intended to prevent a server timeout so that all pages can be indexed correctly. The default values for both settings are usually sufficient.
Changing the settings does not usually affect the speed of search indexing.