Updating the catalog will update all catalog records and remove invalid records. It does this by clearing all indexes and re-cataloging all currently indexed objects.

Clearing the catalog will remove all entries.

Log progress of reindexing every N objects to the Zope logger (set to 0 to disable logging)

Subtransactions allow Zope to commit small parts of a transaction over a period of time instead of all at once. For ZCatalog, this means using subtransactions can signficantly reduce the memory requirements needed to index huge amounts of text all at once. Currently, subtransactions are only applied to text indexes.

If enabled, subtransactions will reduce the memory requirements of ZCatalog, but at the expense of speed. If you choose to enable subtransactions, you can adjust how often ZCatalog commits a subtransactions by adjusting the threshold below.

If you are using ZCatalog and ZSQL Methods in the same transaction, you must disable subtransactions, they are not compatible with ZSQL Methods.

Subtransactions are Enabled Disabled

The Subtransaction threshold is the number of objects cataloged in the context of a single transaction that the catalog will index before it commits a subtransaction. If this number is low, the Catalog will take longer to index but consume less memory. If this number is higher, the Catalog will index quickly but consume much more memory.