Class Reference
Cache for UNIX 2018.1.1
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persistent class %SYS.Maint.Bitmap extends %Persistent

This utility is used to compress bitmap indices. Over time in a volatile table (think lots of INSERTs and DELETEs) the storage for a bitmap index will become less and less efficient. To a lesser extent index value changes, for example OrderStatus changing from Open to Closed, can also degrade bitmap performance.

This utility can by run on a live system. It will loop over all bitmap indices in a class or namespace and compress them by either removing a chunk that is all zeros or by using $BITLOGIC() to compress the bits.

The Utility has 2 entry points:

	d ##class(%SYS.Maint.Bitmap).Namespace("Samples",1,1,"2014-01-17 09:00:00")
	d ##class(%SYS.Maint.Bitmap).OneClass("BitMap.Test",1,1)

Inventory

Parameters Properties Methods Queries Indices ForeignKeys Triggers
12 4


Summary

Properties
ClassName CompressionAmount ElapseTime IndexName
Message Namespace NewSize NumberCompressed
OldSize StartTime Status StopTime

Methods
%AddToSaveSet %AddToSyncSet %BMEBuilt %CheckConstraints
%CheckConstraintsForExtent %ClassIsLatestVersion %ClassName %ComposeOid
%ConstructClone %Delete %DeleteExtent %DeleteId
%DispatchClassMethod %DispatchGetModified %DispatchGetProperty %DispatchMethod
%DispatchSetModified %DispatchSetMultidimProperty %DispatchSetProperty %Exists
%ExistsId %Extends %GUID %GUIDSet
%GetLock %GetParameter %GetSwizzleObject %Id
%InsertBatch %IsA %IsModified %IsNull
%KillExtent %KillExtentData %LoadFromMemory %LockExtent
%LockId %New %NormalizeObject %ObjectIsNull
%ObjectModified %Oid %OnBeforeAddToSync %OnDetermineClass
%Open %OpenId %OriginalNamespace %PackageName
%PhysicalAddress %PurgeIndices %Reload %RemoveFromSaveSet
%ResolveConcurrencyConflict %RollBack %Save %SaveDirect
%SaveIndices %SerializeObject %SetModified %SortBegin
%SortEnd %SyncObjectIn %SyncTransport %UnlockExtent
%UnlockId %ValidateIndices %ValidateObject Namespace
OneClass


Properties

• property ClassName as %String(MAXLEN=500);
Namspace that was compacted Last Class Compacted, if NULL then it finished all the classes.
• property CompressionAmount as %String [ Transient ];
• property ElapseTime as %Integer [ Transient ];
• property IndexName as %String(MAXLEN=500);
Last Index Compacted, if NULL then it finished all the indices.
• property Message as array of %String(MAXLEN=30000);
Message contains error info and lists of global that were skipped because they where not in the local DB
• property Namespace as %String(MAXLEN=500);
• property NewSize as %Integer [ InitialExpression = 0 ];
• property NumberCompressed as %Integer [ InitialExpression = 0 ];
count of how many indices were compacted
• property OldSize as %Integer [ InitialExpression = 0 ];
• property StartTime as %TimeStamp;
when the last Compact was started
• property Status as %String;
current status of the compaction Running - Compaction is underway Stopped - Compaction reached the Duration limit before finishing all Classes or encountered an error Finished - Compaction completed.
• property StopTime as %TimeStamp;
Passed in Timestamp for when the compact should stop, NULL for no stop time Set to the time the compaction finshed when done.

Methods

• classmethod Namespace(ns As %String, NoJournal As %Boolean = 0, Display As %Boolean = 0, StopTime As %TimeStamp = "") as %Status [ SQLProc = ]

Entry point to compact all bitmaps in a namespace.
Each run records its' status in this class
If the last run did not finish then it will pick up where it stopped
This utility will only Compact globals in the default database

Parameters:

  • ns - Namespace you want to compact
  • NoJournal - Stop journaling for this Process
    • 1 to Stop Journaling
    • 0 to continue Journaling default = 0
  • Display - write info to the current device
    • 1 to write to the device
    • 0 to not write to the device default = 0
  • StopTime - Timestamp for when the utility should stop.
    • The stop time is tested after each index is finished so it could go over.
    • A value of NULL means not limit
• classmethod OneClass(ClassName As %String, NoJournal As %Boolean = 0, Display As %Boolean = 0, StopTime As %TimeStamp = "", StatusObj As %CacheObject = "") as %Status [ SQLProc = ]

Entry point to compact all bitmaps in one class.
Each run records its' status in this class
This utility will only Compact globals in the default database

Parameters:

  • ClassName - Class you want to compact
  • NoJournal - Stop journaling for this Process
    • 1 to Stop Journaling
    • 0 to continue Journaling default = 0
  • Display - write info to the current device
    • 1 to write to the device
    • 0 to not write to the device default = 0
  • StopTime - Timestamp for when the utility should stop. The stop time is tested after each index is finished so it could go over.
    • a value of NULL means not limit
  • StatusObj - This is either passed in from the Namespace Method or is defined in this method.
    • This value should not be passed in if you are calling this method directly


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