Why does a certified messaging ledger file not shrink on the Mainframe?
Article ID: KB0085558
Updated On:
| Products | Versions |
|---|---|
| TIBCO Rendezvous | - |
| Not Applicable | - |
Description
Resolution:
RV uses C-level stdio routines on the OS/390, which do not provide a mechanisim for truncating the file. So the ledger file on the mainframe will never shrink.
As the messages get confirmed they are marked for deletion and the pre-allocated space is re-used when a new message arrives.
Ledger files use the following general storage allocation scheme:
a) Each ledger acquires a pool of storage, and manages that pool. The ledger reuses existing storage whenever possible. Ledger files grow as needed.
b) Ledger files grow by adding storage in integer multiples of a minimum allocation size.
c) Since storage allocation involves expensive operating system calls, ledger files pre-allocate large blocks of storage to reduce the number and frequency of such calls.
d) Rendezvous software automatically reclaims ledger file storage on operating systems that support this feature. OS/390 does not support this feature.
RV uses C-level stdio routines on the OS/390, which do not provide a mechanisim for truncating the file. So the ledger file on the mainframe will never shrink.
As the messages get confirmed they are marked for deletion and the pre-allocated space is re-used when a new message arrives.
Ledger files use the following general storage allocation scheme:
a) Each ledger acquires a pool of storage, and manages that pool. The ledger reuses existing storage whenever possible. Ledger files grow as needed.
b) Ledger files grow by adding storage in integer multiples of a minimum allocation size.
c) Since storage allocation involves expensive operating system calls, ledger files pre-allocate large blocks of storage to reduce the number and frequency of such calls.
d) Rendezvous software automatically reclaims ledger file storage on operating systems that support this feature. OS/390 does not support this feature.
Issue/Introduction
Why does a certified messaging ledger file not shrink on the Mainframe?
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