LOG-ROLLING COMPROMISE in .NET framework

Painting QR Code in .NET framework LOG-ROLLING COMPROMISE
LOG-ROLLING COMPROMISE
QR Code 2d Barcode Scanner In VS .NET
Using Barcode Control SDK for .NET framework Control to generate, create, read, scan barcode image in VS .NET applications.
At one trading institution, tensions arose between operations people running a trading system and businesspeople looking to real-time reporting of activity to help identify trades that went outside of acceptable risk levels. The operations crew felt that adding a risk management step would slow down trade reporting, possibly introducing some regulatory issues. How to get through the impasse Log replication to the rescue! Logs from the trading system were copied to the risk management system, where they were used to insert transactions into the risk management database as if it was directly connected to the trading system. The trades were entered into risk management in real time, plus the log transfer interval of a few minutes, making everyone happy and eliminating a possible bottleneck on the trading system. Hal
Create QR Code 2d Barcode In Visual Studio .NET
Using Barcode maker for VS .NET Control to generate, create QR Code image in VS .NET applications.
Database Replication Managers
Quick Response Code Scanner In .NET Framework
Using Barcode decoder for .NET framework Control to read, scan read, scan image in Visual Studio .NET applications.
One step above database administrator directed log transfers on the replication food chain are commercial database replication management products. Some, such as Oracle Replication Server, are offered as part of the database management system, and others, such as Quest SharePlex, are third-party products. To replicate databases, a database replication manager application walks through the log files and copies the transactions to one or more replica databases. Instead of relying on the recovery manager to roll the logs, the replication manager mimics an application performing the workload represented
Drawing Bar Code In Visual Studio .NET
Using Barcode creation for .NET Control to generate, create barcode image in VS .NET applications.
Data Replication
Decoding Barcode In Visual Studio .NET
Using Barcode decoder for Visual Studio .NET Control to read, scan read, scan image in Visual Studio .NET applications.
by the log files. The process that picks apart the log files and reconstructs the transaction is commonly called a transfer manager, and it can write to one or more target machines that have a local replay manager acting as a database application. Replication is typically done asynchronously; that is, the log files are scanned by the manager after the transaction has already been applied to the primary system, and without any locking or checkpointing to ensure that the transfer manager and the primary application coordinate updates to all databases. As a result, it s possible for the transfer manager to be several transactions behind the primary application database, slowed by the time required to walk the logs and apply transactions to the secondary machines. As with log replay, there are design considerations for database replication managers:
Creating QR Code 2d Barcode In Visual C#.NET
Using Barcode maker for .NET framework Control to generate, create QR-Code image in .NET framework applications.
The relationship between insert rate, update rate, and the log transfer manager s ability to extract transactions must be clearly understood. Under high insert and update conditions, does the transfer manager run into contention for access to the log files The longest delay you ll see under extreme conditions must be known. One way to accomplish this is to watch the number of transactions that go into the log transfer manager queue. If you can only replicate 10 transactions a second but have insert peaks of 50 transactions a second, you ll push 40 transactions a second off into the transfer manager. You may end up with a delay of a few minutes while waiting for the replicated databases to absorb these load peaks. Some database replication managers can fail completely once the load exceeds a certain level. These solutions are not appropriate for largescale operations with heavy-duty levels of transactions. Speak to your vendor and determine their rated limits for transaction throughput. What happens when the primary database fails Does the transfer manager fail as well, requiring applications to do the ask then restart recovery outlined previously If the transfer manager continues to apply updates, how can a client application determine when it s acceptable to connect to another copy of the database When the primary returns to service, what happens to the log transfer manager The secondary database (now acting as the primary) has probably reinserted all of the transactions that were entered into the queue in the transfer manager at the time of the primary failure. Should the transfer manager flush its queue Should it remain quiescent until restarted by the database administrator
QR Code ISO/IEC18004 Printer In .NET Framework
Using Barcode printer for ASP.NET Control to generate, create QR Code ISO/IEC18004 image in ASP.NET applications.
Making Quick Response Code In Visual Basic .NET
Using Barcode generator for VS .NET Control to generate, create Quick Response Code image in Visual Studio .NET applications.
Make Bar Code In .NET
Using Barcode printer for Visual Studio .NET Control to generate, create barcode image in .NET applications.
Make UPC E In .NET Framework
Using Barcode creator for VS .NET Control to generate, create GTIN - 12 image in VS .NET applications.
Bar Code Creation In .NET
Using Barcode creator for ASP.NET Control to generate, create barcode image in ASP.NET applications.
Making EAN128 In Visual C#
Using Barcode generator for .NET framework Control to generate, create UCC - 12 image in .NET framework applications.
Paint UPC Symbol In C#
Using Barcode printer for VS .NET Control to generate, create UPC-A Supplement 5 image in .NET applications.
ECC200 Maker In VB.NET
Using Barcode creation for .NET framework Control to generate, create Data Matrix image in VS .NET applications.