Product Overview
Enterprise Database Server for ClearPath MCP provides a highly available environment that supports large databases and high-volume online transaction processing. It accommodates installations of virtually any size. Enterprise Database Server offers exceptional flexibility in accommodating a broad variety of data models—hierarchical, network, flat, or relational. Enterprise Database Server also supports a variety of information-accessing techniques. It incorporates validation, audit/recovery, and access control capabilities, as well as supporting optional utilities for database analysis, monitoring, integrity certification, online reorganization, and online archiving.
The three goals of Enterprise Database Server are linear scalability, multiterabyte capacity, and database availability.
Linear scalability
As each processor is added to a system, it should ideally yield the same amount of performance increment as the processor that preceded it.
Multiterabyte capacity
Enterprise Database Server provides multiterabyte data capacity at the data set level. Each data set can hold more than 12 terabytes of data.
Database availability
Enterprise Database Server seeks to reduce the amount of time during which a database or structure is unavailable because of required maintenance or recovery tasks. Enterprise Database Server addresses this goal by providing an online garbage collection facility for disjoint index sequential sets and subsets.
General Features
Enterprise Database Server supports a variety of information-accessing techniques. You can store groups of data records (called data sets) in several primary ways, including those shown in the following table.
|
File Structure Type |
Description |
|---|---|
|
Standard |
Records are generally not ordered in this structure type. To provide efficient keyed access to a particular data record, indexes are often used. A single standard data set can have multiple indexes, allowing keyed access for many different selection conditions. |
|
Direct |
Records are stored and accessed by a unique user-supplied “record number,” which eliminates the need for a separate index to find a particular data record. Direct data sets allow you to specify other indexes to enable efficient searches by other keys. |
|
Hashed |
A designated key of this record type is hashed and the records are stored in the hashed order. The hashed file structure provides fast access without an additional index structure. No indexes are allowed on this structure type. The hashed key can be alphanumeric as well as numeric. |
|
Ordered |
A designated key of this record type is used to order the records as they are stored. |
Enterprise Database Server incorporates a variety of validation, audit/recovery, and access control capabilities. Comprehensive audit and recovery facilities provide
-
Restart information for user programs
-
Automatic recovery of the database when faults occur
-
Reconstruction of portions of the database
-
Removal of canceled transactions
Full recovery of all completed transactions is available within Enterprise Database Server when it enforces independent transactions. You can synchronize a Transaction Server audit trail with the Enterprise Database Server audit trail to provide full synchronized recovery.
Several Enterprise Database Server utilities are available that support database analysis, monitoring, integrity certification, online reorganization, and online archiving. These products enhance the overall usability of Enterprise Database Server and help clients approximate a 24-hour online, 7-day-a-week operation. All messages generated by Enterprise Database Server are compatible with the MultiLingual System (MLS), which allows you to translate messages into your local language. The released language is English.
Hot Software Update
The hot software update feature provides enhanced database availability during software installation of an Enterprise Database Server Interim Correction (IC) or a Supplemental Support Package (SSP). You can update your Enterprise Database Server software from an IC or SSP without bringing down your database or application. Three update types are provided for smooth transitions: controlled, assisted, and automatic.
You can
-
Run a database environment that does not need to be disabled or discontinued during software installation.
-
Experience minimum performance interruptions to an application environment during installation.
-
Use programmatic guidelines for user applications to participate with the software update process. These programmatic guidelines are provided only for programs that link directly to server libraries associated with an active database, such as DMSUPPORT and RDBSUPPORT.
Set Sectioning
Set sectioning in Enterprise Database Server allows multiple set files for specifying greater key range indexes. You can maintain the existing functionality and extend the scalability of set definitions. In addition, an index sequential set can consist of up to 512 physical files within an Enterprise Database Server database.
Databases in Permanent Directories
Enterprise Database Server databases can take advantage of the MCP DATAPATH task attribute so that these databases can reside within permanent directories. Permanent directory databases provide a mechanism to grant common database access without needing to use common usercodes or chargecodes. The mechanism provides security and control at both the macro and micro levels. Use of this mechanism does not affect existing databases. Permanent directory database names are prefixed with *DIR and can contain multiple nodes ahead of the node that identifies the database. For example, the database named MAIN-DB would have file names as follows:
*DIR/NODE1/NODE2/MAIN-DB/<data set name>/DATA *DIR/NODE1/NODE2/MAIN-DB/<data set name>/<set name>
Setting the DATAPATH task attribute for an existing database requires
-
A simple DASDL UPDATE (no format changes)
-
Recompiling all tailored Enterprise Database Server components
-
The same manual copying steps that are required when changing pack locations for database structures and tailored software
Large Objects (LOBs)
Enterprise Database Server supports data types known as large objects (LOBs). These data types enable you to store and manage images, audio files, multimedia files, and Extensible Markup Language (XML) files. LOBs are categorized as either binary large objects (BLOBs) or character large objects (CLOBs) and can be physically stored outside the database (external) or inside the database (internal).
External large objects can be physically stored outside the Enterprise Database Server database in the Windows or MCP file systems. The Enterprise Database Server database contains a pointer to the location of the externally stored data. External LOBs can be accessed through OLE DB Data Provider for ClearPath MCP or through the ClearPath MCP host language interface.
Multiple Dump for a Single Tape
You can perform multiple dumps from the same database or a different database. These dumps are written to a single logical tape. The feature enables easy storage and access of multiple, small Enterprise Database Server DMUTILITY dumps to be backed up to and retrieved from single high volume media
Online Garbage Collection
Online garbage collection returns unused structure space to the system while your database is up and running. This capability enables you to consolidate unused space in sets/subsets and rebalance index structures to optimize access through sets.
When you use garbage collection, the database remains online and available, and any failure of the garbage collection task has no impact on the database.
Record Serial Numbers (RSNs)
A record serial number (RSN) is a unique number assigned to each data-set record. A RSN is guaranteed to be unique within a data set but not within the database. That is, once an RSN is used within a data set that RSN is never used again within that data set, but it can be used for a record in another data set.
RSNs enable an internal optimization within sets that allows duplicates but that does not declare DUPLICATES FIRST or DUPLICATES LAST.
REORGDB Feature
The REORGDB feature enables you to
-
Improve productivity by reorganizing the database or selected structures while your applications run.
-
Gain scalability where you need it. Enterprise Database Server continues to support mixed structures in a single database.
-
Improve database availability by allowing existing applications that are not affected by the reorganization to operate continuously; no explicit close and re-open operations are necessary. Applications affected by the reorganization continue to operate until the reorganized structures are ready to be placed into service.
The REORGDB mode provides the following key features:
-
A live Enterprise Database Server database remains open with all structures available during a database or structure reorganization.
-
Existing applications affected by the reorganization remain active until the background reorganization completes and the newly reorganized structures are activated. Existing applications not affected by the reorganization remain continuously active and no longer need an explicit close or re-open operation.
-
Updates to a live database are captured during the background reorganization and used automatically to synchronize the reorganized database structures.
-
Easy, graphical access through the Database Operations Center to all Enterprise Database Server reorganization modes—Online, Offline, and REORGDB—is available.
-
A choice to automatically swap the live database or to have the system notify you when the reorganization and synchronization steps are complete.
Sectioned Audit Files
Sectioned audit files involve the use of multiple physical files that together form a single logical audit file. You can define up to 63 individual audit sections; however, the combination of all the sections makes up the logical audit file. All sections of an audit file must be present for Enterprise Database Server Extended Edition to recognize that the audit file is present.
Sectioned audit files Improve audit trail throughput, provide concurrent multiple audit file I/Os, and increase the bandwidth of the audit trail.
Sectioned Data Sets
As with sectioned audit files, a sectioned data set is one in which the logical data set structure is physically composed of multiple physical files. You can define up to 255 sections for a data set; however, it is the combination of all the sections that make up the logical data set.
Sectioned data sets are provided for disjoint standard data sets only. Records in the data set are distributed among the sections using a round-robin algorithm.
Use of sectioned data sets provides the following advantages:
-
Reduction or elimination of throughput restrictions imposed by the architecture of internal locks within Enterprise Database Server.
-
Increased bandwidth of Enterprise Database Server physical I/O.
-
Expanded data set capacity—multiple physical files expand the data set capacity from 48 gigabytes per structure to 48 gigabytes per section. With a possible 255 sections per data set, each data set has a potential capacity of 12 terabytes.
-
Visibility of existing application program logic—logically, sectioned data sets appear identical to nonsectioned data sets. Consequently, when migrating to sectioned data sets, no application program changes are required. With the exception of the possible appearance of an RSN item (which is visible to the application only if declared in the DASDL), application programs are unaware that a data set is sectioned.
Sectioned Sets
A sectioned set is one that has been divided, based on criteria specified in DASDL, into several discrete components that enable access or manipulation of each section independently of the other sections.
When multiple application programs access a data set by way of a set, some contention for set resources occurs. As the number of programs rises, so does the amount of contention. Set sectioning reduces, and in some cases eliminates, set resource contention.
Sectioning of sets is critical for achieving scalability on systems with many processors and databases with large data sets.
Sectioned sets are provided for disjoint indexed sequential sets only.
TranStamp Locking
TranStamp locking is a type of locking algorithm for data sets that are defined in DASDL with a special keyword. The TranStamp locking algorithm makes the data record an integral part of the locking process. With the aid of a unique transaction identifier, TranStamp locking provides a substantial increase in record-lock related performance.
To allow for ease of migration, the use of TranStamp locking is optional for nonsectioned data sets. However, the full benefit of TranStamp locking is not realized unless it is used by all structures in the database.
Some of the advantages offered by TranStamp locking are as follows:
-
The data record is made part of the locking scheme, which eliminates much of the overhead required to manage internal lock tables.
-
The size of the lock table is reduced from one entry per locked record to one entry per transaction.
-
The limit on the number of records that can be locked by a single program is eliminated because the lock table requirements for a given program are fixed.
-
The overhead associated with END-TRANSACTION operations is reduced because all records can be freed by invalidating the TranStamp identifier associated with the lock (as opposed to freeing each locked record).
Tape Encryption
The Enterprise Database Server tape encryption feature enables you to encrypt dump files and audit files using Enterprise Database Server tape encryption. You can encrypt data files when they are copied from disk to tape or from disk to disk as part of a DMUTILITY DUMP operation. You can also encrypt audit files when they are copied from disk to tape as part of a COPYAUDIT QUICKCOPY operation.
To use this feature, you must have a license for the Tape Encryption product (CSP10nn-MTE), which is described earlier in this document.
Variable Audit Buffers
Varying the number of audit buffers when audit files are sectioned enables the database to absorb short periods of intense audit activity. The number of audit buffers automatically changes as the number of audit file sections increases or decreases, with approximately 10 audit buffers allocated for each section. Although the system adjusts the number of audit buffers automatically, you can also manually assign the number.
Verification of Quiesced Database
You can verify the physical integrity of a database copy created with the QUIESCE command, prior to, or during the recovery process.
Data Masking
This feature prevents casual viewing of sensitive data. Database and Security Administrators can obscure or de-identify specific data within a DMSII database, ensuring that security is maintained and that sensitive information is not leaked outside authorized environments. This feature provides less protection than encryption, but the overhead/cost is much lower than for encryption.
Security Logging
Security Logging is a system logging option that captures and records information associated with an Enterprise Database Server Security exception (for example, CATEGORY 17). The pertinent information captured is application name, database identity (that is, mix number, stack number), structure name, and the DM VERB TYPE that is in violation.
Record Count
A DASDL RECORDCOUNT option enables the database system to automatically store the number of records in a structure. This option is valid for disjoint datasets and sets. This information is often required by auditors.
Automatic READERROR Correction
This feature is a DMUTILITY dump option that enables an area of a data file previously flagged with READERROR to be dynamically corrected. The correction occurs automatically following the successful read of the entire area by DMUTILITY.
Data Access Logging
Data access logging provides the ability to log any access of a database including inquiries. Log entries are placed in the system Sumlog and include this information:
-
Name of program
-
User code and access code of the executing program
-
Structure name and number
-
Record address.
New Features/Enhancements
The new feature/enhancement for this release is an NFS that encrypts audit images when they are transferred over a network.
Ordering Information
Enterprise Database Server is included as part of the operating environment. Source code is available for Enterprise Database Server. It is included as part of the operating environment source product, which you can license separately.
Product Information
Refer to the following documents for more information:
-
Enterprise Database Server for ClearPath MCP Application Program Interfaces Programming Guide (8600 2409)
-
Enterprise Database Server for ClearPath MCP Data and Structure Definition Language (DASDL) Programming Reference Manual (8600 0213)
-
Enterprise Database Server for ClearPath MCP Getting Started and Installation Guide (3850 8198)
-
Enterprise Database Server for ClearPath MCP Utilities Operations Guide (8600 0759)
-
Importing and Exporting Database Schemas Guide (3845 8238)
