监控表字段

Question

我已经开始检查监控表了。有人可以解释这些字段的含义吗？

 MON$TRANSACTIONS (started transactions)
             - MON$TOP_TRANSACTION (top transaction)
             - MON$OLDEST_TRANSACTION (local OIT number)
             - MON$OLDEST_ACTIVE (local OAT number)
MON$TRANSACTIONS (started transactions)
         - MON$TRANSACTION_ID (transaction ID)
         - MON$ATTACHMENT_ID (attachment ID)
         - MON$STATE (transaction state)
             0: idle
             1: active
         - MON$TIMESTAMP (transaction start date/time)
         - MON$TOP_TRANSACTION (top transaction)
         - MON$OLDEST_TRANSACTION (local OIT number)
         - MON$OLDEST_ACTIVE (local OAT number)