LUSID is a transaction-based system. It does not maintain a static record of your holdings (positions) in a portfolio but rather generates them on demand from the stored history of transactions, replayed in date order. More information.
The first time you perform an operation such as retrieving holdings or valuing a portfolio, LUSID establishes a cache of calculated holdings that make subsequent operations faster.
Certain operations invalidate the holdings cache, which means slower performance until LUSID can establish it again. It might be optimal to reduce the number of these operations, or coalesce them.
Operations that invalidate the holdings cache for a portfolio are:
Editing existing transactions.
Setting or adjusting holdings.
Loading backdated corporate actions
Changing characteristics of the portfolio itself, such as name, description, sub-holding keys, creation date, instrument scopes and so on.
Changing tax rule sets and amortisation rule sets.
Changing transaction types.
Changing underlying instrument definitions.
Changing calendars (if instrument events are enabled).
Changing quotes (if instrument events are enabled).