Product Documentation

Database Administrator's Guide

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Configurable Extended Transaction Number Options

To check for files that do not support extended transaction numbers, add the following keyword to the FairCom Server configuration file:

DIAGNOSTICS EXTENDED_TRAN_NO

This keyword causes the server to log each physical open of a non-extended transaction number file to the CTSTATUS.FCS file. The reason to check for a file that does not support extended transaction numbers is that if all files do not support extended transaction numbers, then the exceptions could cause the server to terminate if the transaction numbers exceed the original 4-byte range and one of these files is updated. By “all files” we mean superfile hosts and indexes; data files are not affected by the extended transaction number attribute.

To enforce the use of only files with extended transaction numbers, add the following keyword to the FairCom Server configuration file:

COMPATIBILITY EXTENDED_TRAN_ONLY

This keyword causes a R6BT_ERR (745) on an attempt to create or open a non-extended-transaction-number file. A read-only open is not a problem since the file cannot be updated.

These configuration options have no effect on access to non-transaction files, as transaction numbers are not relevant to non-transaction files.

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Configurable Transaction Number Overflow Warning Limit

When FairCom DB supports 6‑byte transaction numbers it does not display transaction overflow warnings until the current transaction number approaches the 6‑byte transaction number limit. But if 4‑byte transaction number files are in use, a key insert or delete will fail if the current transaction number exceeds the 4‑byte transaction number limit (however, FairCom DB will continue operating).

To allow a server administrator to determine when the server’s transaction number is approaching the 4‑byte transaction number limit, the following configuration option was added:

TRAN_OVERFLOW_THRESHOLD <transaction_number>

This keyword causes the c-tree Server to log the following warning message to CTSTATUS.FCS and to standard output (or the message monitor window on Windows systems) when the current transaction number exceeds the specified transaction number:

WARNING: The current transaction number (####) exceeds the user-defined threshold.

The message is logged every 10000 transactions once this limit has been reached. The TRAN_OVERFLOW_THRESHOLD limit can be set to any value up to 0x3ffffffffffff, which is the highest 6‑byte transaction number that FairCom DB supports.

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