09/14/2004InterBase 7.5 overview.
Features and Goals of Release
- SQL Functionality
- Global temporary tables - like a regular table but data goes away at the end of transaction or attachment. Each attachent sees its own data only. Can be indexed. SQL Standard doesn't allow constraints between regular and temporary tables.
- CASE, COALESCE, NULLIF
- SQL Performance
- Memory management algorithms changed to better fit a server architecture. SMP support exploited to increase allocation speed.
- Allows memory to be reclaimed and returned to the OS more regularly. Stored procedure clones, internal queries, and the like can't hold memory for extended periods of time anymore. By default done every five minutes, but can be done manually via performance monitoring or you can change the default.
- Sort buffer allocations optimized to reduce page faults.
- Page size limit increased to 16K, page buffer limit increased to 131,000 -- allows use of full 2GB address space available to process. Don't combine these two maximum values as IB does need some memory for other things!
- Page cache will be dynamically expanded for increased client loads.
- I/O strategies: Two new alternatives to forced writes or asynchronous writes:
- Asynchronous writes with periodic flush -- IB guarantees a write cache flush every so often, can be triggered manually or scheduled. Pages written in order of optimal performance, with intra-thread coordination.
- "Group commit" (careful writes done in background thread).
- Database linger prevents server from freeing up memory when all attachments detatch. Good for cases where users frequently connect and disconnect, like a web application. Can be configured with the interval of your choice. Also allows garbage collection or sweep to continue.
- Server performance -- SMP
- Atom synchronization improved; prevents excessive thread switching for high-frequency, short locks. Means IB can use maximum CPU power.
- Improved SMP performance by changing page latches to reduce need for multithreaded synchronization. Long-running procs and queries should see 100% - 300% improvement; sweep can be three times faster.
- JDBC driver improved -- supports savepoints, remote protocol improved.
- Security
- Embedded user authentication allows storage of user data in DB file instead of central admin.ib file. Can maintain user accounts with DDL-like commands. Can set default ROLE (for embedded users). Can create a SYSDBA user (with usual privileges) but it isn't required. Users can change their own passwords.
- Deployment
- Can run multiple versions of IB on a single server machine (as long as at least one of them is 7.5 or higher).
- Ease of use
- Server-side DB aliases. Defined in admin.ib table DB_ALIAS.
- Performance monitoring improvements.
