|Subject||RE: [firebird-support] Another ordering question?|
> Well, with all transaction numbers within a few hundred of each otherActually, there are 480 transactions between you and the OAT.
> Oldest transaction 391428664
> Oldest active 391428665
> Oldest snapshot 391428665
> Next transaction 391429145
> so that doesn't look like the explanation ...First, you need to remember that FB indexes are transactionless -- they simply store the values, without context of the value for a given transaction.
Accordingly, the engine must fetch/read each row to determine the field value(s) for a given transaction.
So, while the engine can "walk" the index for the order, it still must confirm whether the row is active for a transaction and what the correct field values(s) are.