The version 7.0 MicroKernel provides several new features and performance enhancements. Here is a brief description:
Large Files. Data files that use the 7.x format can expand up to 64 GB. Btrieve applications treat the large file as a single, logical data file, but at the operating system level the large file consists of up to 32 two-gigabyte files. This 2 GB limit allows the large file to be portable across all Btrieve-supported platforms. For more information, read "Large Files" in the Pervasive.SQL User's Guide.
Developers: The MicroKernel's large file support feature requires a maximum of 256 records per page. This limit can affect the optimum page size in files that have very small records and very large page sizes. For more information, read "Designing the Database" in the Btrieve Programmer's Guide.
Transaction Durability. The 7.0 MicroKernel employs a new transaction logging scheme that tracks all operations on all files in a single log. This new scheme allows the MicroKernel to guarantee transaction persistence and atomicity, improve performance, and use a larger system transaction size.
Transaction durability is accomplished by uniquely identifying each record, either by a user-defined unique key or by a system-defined log key. System-defined log keys are called system data. Consequently, if a file does not have system data or a unique user-defined key, the file is not "transaction durable."
To determine if a file is transaction durable, retrieve the file's statistics. You can do this using the BUTIL -STAT command, using the Maintenance utility's Create Stat Report command, or calling the Btrieve Stat operation. If you have existing 6.x files that are not transaction durable because they do not have unique user-defined keys, you should add system data. Because the MicroKernel adds system data only to 7.0 files, you must update the file format when you add system data.
To convert a 6.15 file to 7.0 format and add system data, see Chapter 10, "Converting MicroKernel Data Files," in the Pervasive.SQL User's Guide.
In Btrieve 6.x, the Transaction Durability configuration option was turned off by default. In 7.x the option is turned on by default for two reasons. First, guaranteeing transaction persistence and atomicity is beneficial. Second, the default system transaction size is larger than in Btrieve 6.x, which improves performance at the risk of losing more work in the event of a crash if durability were not turned on.
For more information about these topics, read "Transaction Durability" and "System Data" in the Pervasive.SQL User's Guide.
Enhanced roll forward capability. Rolling forward is the process by which you recover changes made to a data file between the time of the last backup and a system failure. Previously, roll forward functions were performed by a separate Roll Forward utility. In Pervasive.SQL 7.0, the MicroKernel performs roll forward tasks when instructed by the Maintenance utility. This enhances roll forward performance and reliability.
Support for more than 64,000 file handles. The 7.0 MicroKernel allows you to assign up to 4 billion file handles. Previously, the MicroKernel limited file handles to 64,000.
Pervasive.SQL Event Logging. The MicroKernel log file has been replaced with a new, centralized event log that Pervasive.SQL components share. This log contains informational, warning, and error messages. When receiving some types of status codes now, more detailed information can be found in this log pertaining to that error. Event logs are generated at both the client and the server machines. For more information, read "Event Logging" in the Pervasive.SQL User's Guide.
International Sort Rules. This feature extends the use of alternate collating sequences by providing a set of multi-weight collation tables you can use to sort international string values with an ISO-defined, language-specific collating sequence. The tables provide for collation in English, French, German, Spanish, and Japanese (Shift-JIS character set). For more information, read "International Sort Rule" in the Pervasive.SQL User's Guide.
Stackable user counts. You can increase the Btrieve user count by supplying a software license key you obtain from Pervasive Software. You can increase the user count incrementally by 10, 20, 50, 100, or to an unlimited number of users. When you reach 200 users, you have an unlimited user count environment. For more information, refer to Chapter 5, "Updating Your User Count License," in Getting Started With Pervasive.SQL.
Smart Components. A new architecture governs how Btrieve's internal client components communicate with one another. By ensuring that outdated or incompatible components are not used by mistake, this architecture improves installation and run-time reliability and makes application trouble-shooting easier. For more information about troubleshooting your installation, read "Troubleshooting Installation Problems," in Getting Started With Pervasive.SQL. For more information about developing Btrieve applications in the Smart Components environment, read "Btrieve Component Architecture" in the Btrieve Programmer's Guide.
