Specifying Hyperion Essbase Kernel Settings

This chapter provides a table that lists the major Hyperion Essbase kernel settings and tells you how to change them. It contains the following sections:

• About Hyperion Essbase Kernel Settings
• Specifying and Changing Hyperion Essbase Kernel Settings
• Using Hyperion Essbase Application Manager for Database Settings
• Using MaxL or ESSCMD for Database Settings
• Specifying Index Cache Size
• Specifying Data File Cache Size
• Enabling Cache Memory Locking
• Specifying Index Page Size
• Specifying Isolation Level
• Specifying Disk Volumes
• Specifying Data Compression
• Controlling Data Block Size

This chapter assumes that one of the following is true:

• You have read Estimating Disk and Memory Requirements for a Database and Introducing the Hyperion Essbase Kernel .
• You are familiar enough with Hyperion Essbase to know the settings values that you want to use.

About Hyperion Essbase Kernel Settings

You can customize Hyperion Essbase kernel storage settings at the database level--you can have different settings for every database on your server. The information in this section helps you understand what each setting controls and how to adjust each setting. For a table that lists performance-related settings, see Performance-Related Settings.

The major Hyperion Essbase kernel settings that you can customize are the following:

• Index Cache Size
• Data File Cache Size
• Data Cache Size
• Cache Memory Locking
• Isolation Level
• Disk Volumes
• Data Compression

This chapter focuses on how to specify these settings. For background information, see Introducing the Hyperion Essbase Kernel.

Specifying and Changing Hyperion Essbase Kernel Settings

You can specify most Hyperion Essbase kernel settings by using the Database Settings dialog box in Hyperion Essbase Application Manager or by using ESSCMD. In rare cases you may want to use the ESSBASE.CFG server file to specify settings.

CAUTION:

In previous versions of Hyperion Essbase you can specify many Hyperion Essbase kernel settings in the ESSBASE.CFG server file. In Version 5.x and higher, Hyperion Essbase overrides most of the .CFG settings. See Precedence of Settings.

ESSCMDs That Control Database Settings

Two ESSCMD commands control database settings: SETDBSTATE and SETDBSTATEITEM:

• SETDBSTATE exists for compatibility with previous versions and uses the syntax SETDBSTATE parameter value, in interactive mode; for example, SETDBSTATE accessLevel 1.
• SETDBSTATEITEM controls more settings than SETDBSTATE and uses the syntax SETDBSTATEITEM n, in interactive mode. The integer n corresponds to a parameter. For example, SETDBSTATEITEM 4 corresponds to accessLevel. If you do not know a parameter number, you can omit it, and Hyperion Essbase lists all parameters and their corresponding numbers. Hyperion Essbase also prompts you for a database and an application name.
• As with other ESSCMD commands, you can supply an application name, a database name, and parameter values on the command line.
• See the online Technical Reference in the DOCS directory for information about SETDBSTATE and SETDBSTATEITEM commands. See Performing Interactive and Batch Operations Using ESSCMD for information about ESSCMD.

Summary of Database Settings

Hyperion Essbase uses the most recent setting, whether you use SETDBSTATEITEM, SETDBSTATE, or the Database Settings dialog box.

Precedence of Settings

Database settings specified using the Hyperion Essbase Application Manager Database Settings dialog box, alter database in MaxL, or the SETDBSTATE and SETDBSTATEITEM commands in ESSCMD, override ESSBASE.CFG file settings. The batch methods and the dialog boxes provide different ways to change the same database settings. The most recent value of the database setting overrides any previously set value, whether it was set through a command or a dialog box. Both methods permanently override ESSBASE.CFG settings, as the following paragraph explains.

Hyperion Essbase reads the ESSBASE.CFG file when you start the server, and then applies database settings, overriding the ESSBASE.CFG settings. Hyperion Essbase applies a setting from the ESSBASE.CFG file only if you have deleted the database settings. Hyperion Essbase takes the value of the ESSBASE.CFG file setting and uses it as an initial value for the database setting. If you subsequently stop and restart the server, Hyperion Essbase uses the database setting. Hyperion Essbase ignores any changes you make to the setting in the ESSBASE.CFG file, unless you delete the database setting before starting the server. ESSBASE.CFG file settings apply to all databases on a server.

Irrespective of how you enter the settings, some settings take effect immediately, and others take effect the next time the database is started. Therefore, the settings in effect may not be the settings you most recently entered. For information on when settings take effect, see Table 43-1.

To view the most recently entered settings use GETDBSTATE or select Database > Settings in Hyperion Essbase Application Manager. To view the settings currently in effect, use GETDBINFO or select Database > Information in Hyperion Essbase Application Manager.

For information on stopping and starting servers, applications, and databases, see Running Hyperion Essbase, Applications, and Databases.

Using Hyperion Essbase Application Manager for Database Settings

You can set database, application, and server options by using the settings dialog boxes in  Hyperion Essbase Application Manager. This section covers database settings. See Managing Security at Global and User Levels for information on application and server settings.

To check or customize database settings, select Database > Settings in Hyperion Essbase Application Manager.

Figure 43-1: The Database Settings Dialog Box

The dialog box has four tabs, which correspond to the following pages.

The General page includes the following settings:

• Calculations--see Calculating Data for more information.
• Database access--see Managing Security at Global and User Levels for more information.
• Database startup--see the Hyperion Essbase Application Manager online help for more information.
• Retrieval buffers--see Optimizing Your Reports for more information.

The Storage page includes the following settings:

• Data compression--see Specifying Data Compression for more information.
• Cache memory locking--see Enabling Cache Memory Locking for more information.
• Index cache size--see Using Hyperion Essbase Application Manager for Database Settings for more information.
• Index page size--see Specifying Index Page Size for more information.
• Data file cache size--see Specifying Data File Cache Size for more information.
• Data cache size--see Specifying Data File Cache Size for more information.
• Location of disk volumes--see Specifying Disk Volumes for more information.

The Transaction page includes the following settings:

• Isolation level--see Specifying Isolation Level for more information.
• Synchronization point--see Specifying Isolation Level for more information.
• Concurrency parameters--see Specifying Isolation Level for more information.

The Currency page includes settings for currency databases. See Designing and Building Currency Conversion Applications for more information.

Using MaxL or ESSCMD for Database Settings

You can use alter database in MaxL or the SETDBSTATEITEM or SETDBSTATE commands in ESSCMD to set or change database settings. For more information, see the online Technical Reference in the DOCS directory.

You can use MaxL and ESSCMD to write batch scripts that automate database- setting changes. For information about writing ESSCMD scripts, see Performing Interactive and Batch Operations Using ESSCMD. For information about writing MaxL scripts and using MaxL, see the MaxL Language Reference in the online Technical Reference in the DOCS directory.

Using alter database in MaxL

Issue a separate alter database statement for each database setting you want to change. For example, the following MaxL script logs in to Hyperion Essbase, changes three database settings, and logs out:

login admin identified by secretword;
alter database sample.basic enable committed_mode;
alter database sample.basic set lock_timeout immediate;
alter database sample.basic disable create_blocks;
logout;

Using SETDBSTATEITEM in ESSCMD

For simple items, specify the command, item number, application, database, and value:

SETDBSTATEITEM 2 "JILLAPP" "JILLDB" "Y";

For items that require multiple parameters, such as Isolation Level (item 18), specify multiple parameters:

SETDBSTATEITEM 18 "SAMPLE" "BASIC" "1" "Y" "-1";

Use a separate SETDBSTATEITEM command for each parameter; you cannot string item numbers together on the same line.

Specifying Index Cache Size

Index cache size is an important setting; it determines the maximum memory that Hyperion Essbase allocates to hold index information. This section tells you how to specify the setting and assumes that you have decided what value you want. See Sizing Your Index, Data File, and Data Caches for information about determining an appropriate index cache size.

Hyperion Essbase displays setting values in bytes (B) in ESSCMD and in kilobytes (K) in the Database Settings dialog box.

Using the Hyperion Essbase Application Manager

Select Database > Settings and click the Storage tab. Enter the desired value in kilobytes in the Index Cache text box.

Figure 43-2: Setting Index Cache Size

Using MaxL

Use alter database to set index cache size. You may specify the size in bytes (b), kilobytes (kb), megabytes (mb), gigabytes (gb), or terabytes (tb). For example:

alter database sample.basic set index_cache_size 10mb;

Using ESSCMD

Enter SETDBSTATEITEM 12 or SETDBSTATE in ESSCMD and either follow the prompts or supply the required values on the command line, as shown in the following example:

SETDBSTATEITEM 12 "JILLAPP" "JILLDB" "10M"

When using ESSCMD, you can specify the index cache size in bytes (B), kilobytes (K), megabytes (M), or gigabytes (G). ESSCMD displays minimum, maximum, and current values.

Making a Change Effective

A change to the index cache size takes effect the next time you start the database.

Specifying Data File Cache Size

The Data file cache size is an important setting; it determines the maximum memory that Hyperion Essbase allocates to hold data. The data file cache holds data files (.PAG files) in memory.

This section tells you how to specify the setting and assumes that you have decided what values you want. See Sizing Your Index, Data File, and Data Caches for information about determining the appropriate data file cache size.

Hyperion Essbase displays setting values in bytes (B) in ESSCMD and in kilobytes (K) in the Database Settings dialog box.

The minimum value for the data file cache is 8MB (8388608 bytes).

Using Hyperion Essbase Application Manager

Select Database > Settings and click the Storage tab. Enter the desired value in kilobytes in the Data File Cache text box.

Figure 43-3: Setting Data File Cache Size

Using MaxL

Use alter database to set the data file cache size in MaxL. You may specify the size in bytes (b), kilobytes (kb), megabytes (mb), gigabytes (gb), or terabytes (tb). For example:

alter database sample.basic set data_file_cache_size 35mb;

Using ESSCMD

To specify the data file cache in ESSCMD, enter SETDBSTATEITEM 27 and supply the required values on the command line, as shown in the following example:

SETDBSTATEITEM 27 "JILLAPP" "JILLDB" "35M"

When using ESSCMD, you can specify the data file cache size in bytes (B), kilobytes (K), megabytes (M), or gigabytes (G). ESSCMD displays minimum, maximum, and current values.

Making Changes Effective

Changes to the size of the data file cache take effect the next time you start the database.

Specifying Data Cache Size

The data cache holds uncompressed data blocks in memory. In general, if you have to choose whether to allocate memory to the data file cache or to the data cache, choose the data file cache.

This section tells you how to specify the setting and assumes that you have decided what value you want. See Sizing Your Index, Data File, and Data Caches for information about determining the appropriate data cache size.

Hyperion Essbase displays setting values in bytes (B) in ESSCMD and in kilobytes (K) in the Database Settings dialog box.

The minimum value for the data cache is 3MB (3145728 bytes). For compatibility with previous versions of Hyperion Essbase, the Hyperion Essbase kernel accepts a value of 3,000,000 for the data cache and automatically converts the value to the actual minimum of 3MB.

Using Hyperion Essbase Application Manager

Select Database > Settings and click the Storage tab. Enter the desired value in kilobytes in the Data Cache text box.

Figure 43-4: Setting Data Cache Size

Using MaxL

Use alter database to set the data cache or data file cache size in MaxL. You may specify the sizes in bytes (b), kilobytes (kb), megabytes (mb), gigabytes (gb), or terabytes (tb). For example:

alter database sample.basic set data_cache_size 4mb;
alter database sample.basic set data_file_cache_size 35mb;

Using ESSCMD

To specify the data cache in ESSCMD, enter SETDBSTATEITEM 5 or SETDBSTATE and either follow the prompts or supply the required values on the command line, as shown in the following example:

SETDBSTATEITEM 5 "JILLAPP" "JILLDB" "4M"

To specify the data file cache, enter SETDBSTATEITEM 27 in ESSCMD and supply the required values on the command line, as shown in the following example:

SETDBSTATEITEM 27 "JILLAPP" "JILLDB" "35M"

When using ESSCMD, you can specify the data file cache size and the data cache size in bytes (B), kilobytes (K), megabytes (M), or gigabytes (G). ESSCMD displays minimum, maximum, and current values.

Making Changes Effective

Changes to the size of the data cache take effect the next time you start the database.

Enabling Cache Memory Locking

The cache memory locking setting locks the memory used for the index cache, the data file cache, and the data cache into physical memory. Locking improves performance for a Hyperion Essbase database because the system memory manager does not need to swap the memory used by the caches when swapping the Hyperion Essbase server process. By default, cache memory locking is turned off.

Using Hyperion Essbase Application Manager

Select Database > Settings and click the Storage tab. Select the Cache Memory Locking check box.

Figure 43-5: Enabling the Cache Memory Locking Setting

Using MaxL

Use alter database to enable cache memory locking in MaxL. For example:

alter database sample.basic enable cache_pinning;

Using ESSCMD

Enter SETDBSTATEITEM 26 and supply the required values on the command line, as shown in the following example:

SETDBSTATEITEM 26 "JILLAPP" "JILLDB" Y

Making a Change Effective

A change to the cache memory locking setting takes effect the next time you start the database.

Specifying Index Page Size

The index page holds index entries; an index entry exists for every combination of sparse dimensions.

If direct I/O is in effect, Hyperion Essbase ignores the index page size setting and uses a setting of 8K (8,192 bytes). If buffered I/O is in effect, Hyperion Essbase uses the value that is specified in the Index Page Size text box. In this case, the default setting is 1K (1,024 bytes).

Using Hyperion Essbase Application Manager

Select Database > Settings and click the Storage tab. Enter the desired value in kilobytes in the Index Page text box.

Figure 43-6: Setting Index Page Size

Using MaxL

Use alter database to set the index page size in MaxL. You may specify the size in bytes (b), kilobytes (kb), megabytes (mb), gigabytes (gb), or terabytes (tb). For example:

alter database sample.basic set index_page_size 1024b;

Using ESSCMD

Enter SETDBSTATEITEM 13 or SETDBSTATE in ESSCMD and either follow the prompts or supply the required values on the command line, as shown in the following example:

SETDBSTATEITEM 13 "JILLAPP" "JILLDB" "1024"

When using ESSCMD, you can specify the index page size in bytes (B) or kilobytes (K). The default unit is bytes. ESSCMD displays minimum, maximum, and current values.

Making a Change Effective

A change to the index page setting takes effect the next time you start the database, provided that the database is empty. The database must be empty for the change to take effect.

Specifying Isolation Level

The Hyperion Essbase kernel offers two levels of isolation for transactions: committed access and uncommitted access. Uncommitted access is the default.

Committed access restricts read/write access on data blocks to one transaction at a time; Hyperion Essbase retains write locks on all affected blocks until the transaction commits. Uncommitted access can produce unpredictable results, because Hyperion Essbase acquires and releases write locks as needed during the transaction. Committed access is recommended. For more information on these isolation levels, see Ensuring Data Integrity.

Depending on the type of access that you specify, Hyperion Essbase uses additional parameters, which you can set in Hyperion Essbase Application Manager or in MaxL or ESSCMD.

Notes on Isolation Level Options

If you choose committed access, Hyperion Essbase uses these parameters:

• Pre-image access (enabled by default). Pre-image access provides users read-only access to data blocks that are locked for the duration of a concurrent transaction. Users see the last committed data values for the locked data blocks.
• Wait (dialog box) or time out (ESSCMD).
  • Indefinite wait (the default): The transaction waits to acquire a lock on the required locked block.
  • Immediate access, or no wait: If a required block is locked by another transaction, Hyperion Essbase displays a lock time out message, and the transaction aborts.
  • A number of seconds that you specify: Your transaction waits that number of seconds to acquire a lock on the required locked blocks. If the specified time runs out before the transaction acquires a lock, Hyperion Essbase displays a lock time out message, and the transaction aborts.

    CAUTION:

    Under committed access, Hyperion Essbase retains redundant data until a transaction commits. Allow disk space for double the size of the database to accommodate redundant data.

If you choose uncommitted access, Hyperion Essbase uses these parameters:

• Commit Blocks (number of blocks modified before a synchronization point occurs). The default is 3,000.

  If you set Commit Blocks to 0, the synchronization point occurs at the end of the transaction.

• Commit Rows (number of rows to data load before a synchronization point occurs). The default is 0, which means that the synchronization point occurs at the end of the data load.
• If either Commit Blocks or Commit Rows has a non-zero value, a synchronization point occurs when the first threshold is reached. For example, if Commit Blocks is 10 but Commit Rows is 0 and you load data, a synchronization point occurs after 10 blocks are updated. If Commit Blocks is 5 and Commit Rows is 5 and you load data, a synchronization point occurs after 5 rows are loaded, or 5 blocks are updated, whichever happens first.

CAUTION:

Hyperion Essbase retains redundant data to enforce transactional semantics. Allow disk space for double the size of the database to accommodate redundant data, particularly if both Commit Blocks and Commit Rows are set to 0.

Using Hyperion Essbase Application Manager

Select Database > Settings and click the Transaction tab. Click Committed or Uncommitted in the Isolation Level group.

Depending on the type of access that you specify, the Concurrency Parameters group or the Synchronization Point group is available.

Suppose you want committed access, pre-image access, and a 60-second wait for locked data blocks. Specify settings as in the following example:

Figure 43-7: Example of Setting Committed Isolation Level

Suppose that you want uncommitted access and that you want Hyperion Essbase to perform a commit operation after 10 blocks are updated, or after 10 rows are loaded. Specify settings as in the following example:

Figure 43-8: Example of Setting Uncommitted Isolation Level

Using MaxL

Use alter database to set the isolation level in MaxL. Issue a separate statement for each setting you want to change. For example:

alter database sample.basic enable committed_mode;
alter database sample.basic disable pre_image_access;
alter database sample.basic set implicit_commit after 100 blocks;
alter database sample.basic set implicit_commit after 200 rows;

For the exact syntax you should use to create MaxL statements, see the MaxL Language Reference in the online Technical Reference in the DOCS directory.

Using ESSCMD

Enter SETDBSTATEITEM 18 in ESSCMD and either follow the prompts or supply the required values on the command line.

Choose 1 (committed access) or 2 (uncommitted access, the default). Depending on the type of access that you specify, ESSCMD prompts you for other parameters (or you can supply the values on the command line).

If you choose 1 (committed access), ESSCMD prompts for the following information:

• Pre-image access; Y (Yes) or N (No, the default). Pre-image access provides users read-only access to data blocks that are locked for the duration of a transaction. Users see the last committed data values for the locked data blocks.
• Wait (in the Database Settings dialog box) or time out (in ESSCMD): -1, 0, or n.
  • -1 is indefinite wait.
  • 0 is immediate access, or no wait.
  • n is a number of seconds that you specify.

If you choose 2 (uncommitted access), ESSCMD prompts for the following values. See Notes on Isolation Level Options for important details about these options.

• Number of blocks modified before internal commit
• Number of rows to data load before internal commit

You can also specify isolation level parameters (pre-image access and so on) by specifying parameters 19-22 on SETDBSTATEITEM. Enter SETDBSTATEITEM with no parameters; ESSCMD displays a list that includes each parameter by number, with a description.

Here is an example of using SETDBSTATEITEM to set an isolation level. This example enables committed access and pre-image access and specifies indefinite wait time.

SETDBSTATEITEM 18 "JILLAPP" "JILLDB" "1" "Y" "-1"

For more syntax information, see the online Technical Reference in the DOCS directory.

Making Changes Effective

Changes to the isolation level settings take effect the next time there are no active transactions.

Specifying Disk Volumes

Use disk volumes to specify where you want to store Hyperion Essbase index files (ESSxxxxx.IND) and data files (ESSxxxxx.PAG). See Storage Allocation for information about how Hyperion Essbase allocates storage across volumes.

When you use disk volumes, Hyperion Essbase provides you the following options for each volume:

• Name of the volume
• Maximum space to use on the volume (called Partition Size in Hyperion Essbase Application Manager and Volume Size in ESSCMD)
• File type. You can specify index files, data files, or both index and data files. The default is index and data files on the same volume.
• Maximum file size. The default is 2,097,152 kilobytes (two gigabytes); the default is the recommended value. When Hyperion Essbase reaches the maximum file size, it creates a new file and names it incrementally. For example, when ESS00001.IND is filled to maximum size, Hyperion Essbase creates ESS00002.IND.

Specify the disk volumes in the order in which you want the volumes to be used. You do not have to specify the volume in which Hyperion Essbase is installed as one of the volumes; you can install on one volume and store data on other volumes.

You can tell Hyperion Essbase to stop storing files on a particular volume. Hyperion Essbase can still access the volume as needed, but it no longer stores additional index and data information on the volume. To stop storing information on a volume, select the volume definition that you want to remove, as shown in Figure 43-9, and click Delete.

You set disk volumes on a per database basis. It is possible for more than one database to use space on the same volume, so allocate space carefully. For example, if you specify 7 GB on Volume A for Database 1 and 7 GB on Volume A for Database 2, you have allocated 14 GB for Hyperion Essbase files on Volume A.

CAUTION:

If you specify a volume name but not a volume size, Hyperion Essbase uses all available space on the volume.

For more information, see Storage Allocation.

Using Hyperion Essbase Application Manager

Select Database > Settings > Storage.

1. In the Disk Volume text box, enter the volume name.
2. Specify Partition Size. Partition Size represents the maximum space that Hyperion Essbase uses on the volume. The default value is Unlimited; the minimum is 8,192 kilobytes.
3. Specify File Type.

   You can specify index files, data files, or both. The default is Index + Data.

4. Specify File Size. File Size represents the maximum size that a file specified in File Type can attain before Hyperion Essbase creates a new file. The default value is 2 GB (2097152 kilobytes); the minimum value is 8,192 kilobytes.
5. Click Set.

To stop Hyperion Essbase from storing additional files on an allocated volume (that is, to "deallocate" a volume), enter the volume name in the Disk Volume text box and click Delete. Hyperion Essbase writes no new files to that volume, but continues to access and use files previously created on that volume.

For example, suppose you do not want any more information to be stored on Volume F. Select the volume definition for volume F and press Delete, as shown in Figure 43-9.

Figure 43-9: Deallocating a Volume

Now, Hyperion Essbase stores no additional data on Volume F.

Allocating Storage: An Example

Suppose you want to use up to 20 GB for Hyperion Essbase files on Volume E, 25 GB on Volume F, and 25 GB on Volume G. You are using the default file size limit of 2 GB.

Figure 43-10: Example of Using Disk Volumes

When you load data, Hyperion Essbase stores up to 20 GB on Volume E; if the database is larger than 20 GB, Hyperion Essbase stores the next 25 GB on Volume F, and so on.

Using MaxL

Use alter database to allocate disk volumes in MaxL. First add a disk volume definition, and then change its settings with a separate statement. For example,

on UNIX:

alter database Samp.Basic add disk volume samp.basic.vol3;
alter database Samp.Basic set disk volume samp.basic.vol3 
file_type index_data;

on Windows:

alter database Sample.Basic add disk volume Sample.Basic.C;
alter database Sample.Basic set disk volume sample.basic.C 
file_type index;

For the exact syntax you should use to create MaxL statements, see the MaxL Language Reference in the online Technical Reference in the DOCS directory.

Using ESSCMD

To allocate a new volume, enter SETDBSTATEITEM 23 in ESSCMD and either follow the prompts or supply the required values on the command line.

ESSCMD prompts you for the following values, unless you supply them on the command line:

• The number of new disk volumes you want to add

Then, for each new volume, ESSCMD prompts you for:

• Volume name (for each volume)
• Volume size (maximum space to use on the volume)--The default value is Unlimited; the minimum setting is 8 megabytes.

  When you use ESSCMD, you can specify volume size in bytes (B), kilobytes (K), megabytes (M), or gigabytes (G). ESSCMD displays minimum, maximum, and current values and 0 for unlimited.

• File type--You can specify index files, data files, or both. The default is 3-Index + Data (index and data files on the same volume).
• File size (maximum size that each file specified in File Type can attain before Hyperion Essbase creates a new file)--The default value is 2 gigabytes; the minimum setting is 8 megabytes.

  When you use ESSCMD, you can specify file size in bytes (B), kilobytes (K), megabytes (M), or gigabytes (G). ESSCMD displays minimum, maximum, and current values.

The following example allocates up to 10 gigabytes on Volume E, sets a maximum file size of 2 gigabytes, and specifies that data files should be stored only on E:

SETDBSTATEITEM 23 "JILLAPP" "JILLDB" "1" "E" "10G" "2" "2G"

To change the settings on an allocated volume, enter SETDBSTATEITEM 24 in ESSCMD and either follow the prompts or supply the required values on the command line.

ESSCMD prompts you for the following values, unless you supply them on the command line:

• Volume number. (Use the GETDBSTATE command in ESSCMD to see a list of the currently defined disk volumes and to see the number assigned to each volume.)
• Volume name
• Volume size
• File type
• File size

The following example allocates up to 20 gigabytes on Volume C and sets a maximum file size of 2 gigabytes:

SETDBSTATEITEM 24 "JILLAPP" "JILLDB" "1" "C" "20G" "3" "2G"

To stop Hyperion Essbase from storing additional files on a volume, enter SETDBSTATEITEM 25 in ESSCMD and either follow the prompts or supply the required values on the command line. Hyperion Essbase continues accessing files on the deallocated volume, but does not write new files to it.

ESSCMD prompts you for the following value, unless you supply it on the command line: Delete which volume definition. Use the GETDBSTATE command in ESSCMD to see a list of the currently defined disk volumes and to see the number assigned to each volume.

The following example deallocates the volume that is specified as fourth:

SETDBSTATEITEM 25 "JILLAPP" "JILLDB" "4" 

For more syntax information, see the online Technical Reference in the DOCS directory.

On UNIX, volume_name is a mounted UNIX file system. You must enter a fully qualified path name up to the name of the directory you are using for Hyperion Essbase. Hyperion Essbase automatically appends the \app directory to the path; you do not specify the \app directory. Consider the following examples:

/vol2/essbase 10M

Volume size is the maximum space, in kilobytes, allocated to the volume. The default value is unlimited--Hyperion Essbase uses all available space on that volume.

Making a Change Effective

For new files, changes to the disk volumes setting take effect when you next start the database. Existing files and volumes are not affected.

Specifying Data Compression

Hyperion Essbase uses the data compression parameter to specify whether it compresses data on disk and to specify which, if any, compression scheme it uses. See Introducing the Hyperion Essbase Kernel for information about data compression.

Hyperion Essbase uses the following data compression schemes.

• Bitmap compression, the default. Hyperion Essbase stores only non-missing values and uses a bitmapping scheme.
• Run-length encoding (RLE). Hyperion Essbase compresses repetitive, consecutive values, including zeros and #MISSING values.

You can also disable compression. Compression is enabled by default.

Using Hyperion Essbase Application Manager

To specify data compression, select Database > Settings and click the Storage tab. Select a value from the Data Compression list box.

Figure 43-11: Setting Data Compression

Using MaxL

You can enable or disable data compession and set the data compression type by issuing the alter database statement in MaxL. For example, the following statements might be used in a MaxL script to enable compression and set it to run-length encoding:

alter database Sample.Basic enable compression;
alter database Sample.Basic set compression rle;

Using ESSCMD

You can enable or disable data compression by using SETDBSTATEITEM or SETDBSTATE. To set the data compression type, you must use SETDBSTATEITEM.

Using SETDBSTATEITEM

To enable or disable data compression, enter SETDBSTATEITEM 14 in ESSCMD and either follow the prompts or supply the required values on the command line.

ESSCMD prompts you for the following values, unless you supply them on the command line:

• Data Compression on Disk? Enter Y (Yes, the default) or N (No).
• Data Compression Type. Enter 1 (run-length encoding) or 2 (bitmap, the default).

To specify the data compression type, enter SETDBSTATEITEM 15 in ESSCMD and either follow the prompts or supply the required values on the command line. ESSCMD prompts you for a value of "1" (run length encoding) or "2" (bitmap, the default).

The following example enables Bitmap compression:

SETDBSTATEITEM 14 "JILLAPP" "JILLDB" "Y" "2"

For more syntax information, see the online Technical Reference in the DOCS directory.

Using SETDBSTATE

Enter SETDBSTATE in ESSCMD. Follow the prompts until the last prompt, Data Compression on Disk? Enter Y (Yes, the default) or N (No).

To set the data compression type, you must use SETDBSTATEITEM or the Database Settings dialog box.

For more syntax information, see the online Technical Reference in the DOCS directory.

Making a Change Effective

Changes to the data compression setting take effect immediately as Hyperion Essbase writes data blocks to disk. For blocks already on disk, Hyperion Essbase does not change compression schemes or enable or disable compression. When you change the data compression settings of blocks already on disk, Hyperion Essbase uses the new compression scheme the next time Hyperion Essbase accesses, updates, and stores the blocks.

Controlling Data Block Size

Data block size is determined by the amount of data in a particular combination of dense dimensions. For example, when you change the dense or sparse configuration of one or more dimensions in the database, the data block size changes. Data block size is 8n bytes, where n is the number of cells that exist for that combination of dense dimensions.

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