Active Transactions

InfoSphere® DataStage® BASIC supports nested transactions. Any transaction can include:

• Read and write operations
• Other transactions or subtransactions that can contain other operations or other transactions

When a transaction begins, it is active. If a second transaction begins before the first transaction is committed or rolled back, the new (child) transaction becomes the active transaction while the first (parent) transaction continues to exist but inactively. The child transaction remains active until:

• It is committed or rolled back, when the parent transaction becomes active again
• Another transaction (child) begins and becomes the active transaction

Only one transaction can be active at any time, although many transactions can exist concurrently. Only one transaction can exist at each transaction nesting level. The top-level transaction is at nesting level 1. When no transactions exist, the nesting level is 0.