What Is a Transaction?
A transaction is a unit of data that CES keeps in memory until it is written in the
index. Instead of constantly writing data, CES waits until its memory cache is filled
before committing a transaction. The purpose of this process is to save CPU resources
and prevent disk fragmentation by consolidating information. Furthermore, the maximum
size of a transaction is limited by the available memory, thus if CES has 50 MB of
RAM at its disposal, it commits larger transactions than if it has only 25 MB.
Note: The Coveo administrator can also specify a time limit after which the transaction is automatically written
(see Modifying or Using Advanced Index Parameters) or force-commit the transaction (see Forcing the Commit of a Transaction).
Important: End-users cannot query data contained in an unwritten transaction.