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Shared Memory Performance Enhancement for All Unix Platforms
A shared memory performance enhancement has been enabled for all Unix platforms, starting with the base c-treeACE V11.6 line. The following changes have now been well proven in production use since late fall of 2017.
The Unix/Linux shared memory communication protocol has been changed to improve performance by improving the internal spin operation to be more efficient, especially for relatively short database operations.
Compatibility Note: It is important to recompile the client due to this shared memory change. A server that uses this modified shared memory protocol only supports shared memory connections from clients that also use this new enhanced protocol. If an older client (pre-V11.6) attempts to connect, it will fail with error SHMC_ERR (841) and the server will log the following message to CTSTATUS.FCS:
Fri May 26 12:13:07 2017
- User# 00016 FSHAREMM: The client's shared memory version (3) is not compatible with the server's shared memory version (4)
Performance Enhanced by Reducing Calls to System time() Function
Each function call made by a c-tree client required calling the time() system function to get the starting time of the current request. This revision changes that architecture to reduce the number of these calls, thereby improving performance of each FairCom DB function called by a client application.
Performance Enhanced by Client Function to Get Information for Multiple Connections in a Single Call
When retrieving connection information for many connected c-tree clients, FairCom DB Monitor could take a very long time to return. The bulk of this time was spent in client-by-client connection returns. To reduce this expensive network traffic, a new function was added to obtain all connection information in a single API call. This function is available for all client applications.
FairCom Server now supports a function that returns information for multiple connections in a single call. Prior to the availability of function, a function call from the client to the Server was required for obtaining information about each connection of interest. This new approach greatly reduces network traffic.
