casa  5.7.0-16
 All Classes Namespaces Files Functions Variables Typedefs Enumerations Enumerator Friends Macros Groups Pages
Public Member Functions | Private Attributes | List of all members
casacore::ROIncrementalStManAccessor Class Reference

Give access to some IncrementalStMan functions. More...

#include <IncrStManAccessor.h>

Inheritance diagram for casacore::ROIncrementalStManAccessor:
casacore::RODataManAccessor

Public Member Functions

 ROIncrementalStManAccessor (const Table &table, const String &name, Bool byColumn=False)
 Construct the object for a data manager in the table given the name of the data manager or the column. More...
 
virtual ~ROIncrementalStManAccessor ()
 
 ROIncrementalStManAccessor (const ROIncrementalStManAccessor &that)
 Copy constructor (reference semantics). More...
 
ROIncrementalStManAccessoroperator= (const ROIncrementalStManAccessor &that)
 Assignment (reference semantics). More...
 
void setCacheSize (uInt aSize, Bool canExceedNrBuckets=True)
 Set the cache size (in buckets) to be used by the storage manager. More...
 
uInt cacheSize () const
 Get the cache size (in buckets). More...
 
void clearCache ()
 Clear the caches used by the hypercubes in this storage manager. More...
 
void showIndexStatistics (ostream &os) const
 Show the index used by this storage manager. More...
 
void showBucketLayout (ostream &os) const
 Show the layout of the buckets used by this storage manager. More...
 
Bool checkBucketLayout (uInt &offendingCursor, uInt &offendingBucketStartRow, uInt &offendingBucketNrow, uInt &offendingBucketNr, uInt &offendingCol, uInt &offendingIndex, uInt &offendingRow, uInt &offendingPrevRow) const
 Check that there are no repeated rowIds in the buckets comprising this ISM. More...
 
- Public Member Functions inherited from casacore::RODataManAccessor
 RODataManAccessor ()
 Construct an empty object. More...
 
 RODataManAccessor (const Table &table, const String &name, Bool byColumn)
 Construct the accessor object for a data manager in the table. More...
 
virtual ~RODataManAccessor ()
 
void setProperties (const Record &) const
 Set data manager properties using the fields in the record. More...
 
Record getProperties () const
 Get data manager properties as a record. More...
 
String dataManagerType () const
 Get the data manager type. More...
 
String dataManagerName () const
 Get the data manager name. More...
 
uInt dataManagerSeqNr () const
 Get the data manager sequence nr. More...
 
void showCacheStatistics (ostream &os) const
 Show IO statistics. More...
 

Private Attributes

ISMBasedataManPtr_p
 

Additional Inherited Members

- Protected Member Functions inherited from casacore::RODataManAccessor
DataManagerbaseDataManager () const
 Get the data manager for the given data manager or column name. More...
 

Detailed Description

Give access to some IncrementalStMan functions.

Intended use:

Public interface

Review Status

Reviewed By:
UNKNOWN
Date Reviewed:
before2004/08/25

Prerequisite

Synopsis

The Table system has one or more storage managers underneath. One of these possible storage managers is the IncrementalStMan. This storage manager uses a cache of buckets. The default cache size is defined when the IncrementalStMan object was constructed at the time the table was created.

Sometimes it can be useful to change the cache size. E.g. when the table is accessed in a random way, the hit rate may drop when the cache is too small. The class ROIncrStManAccessor makes it possible to change the cache size in a temporary way.
Furthermore this class makes it possible to show the cache size and to show the cache statistics.

Motivation

In principle a pointer to IncrementalStMan could be used. However, that would give access to all public functions. Furthermore it could not distinguish between read/write and readonly tables.

Example

This example shows how to set the cache size for the incremental storage manager with the name "ISMExample". The cache size is not persistent, i.e. when the same table is reopened at a later time, this cache size is not remembered.

// Open a table.
Table table("someName.data");
// Set the cache size of its incremental storage manager ISMExample
// to 5 buckets.
ROIncrementalStManAccessor accessor(table, "ISMExample");
accessor.setCacheSize (5);

Definition at line 100 of file IncrStManAccessor.h.

Constructor & Destructor Documentation

casacore::ROIncrementalStManAccessor::ROIncrementalStManAccessor ( const Table table,
const String name,
Bool  byColumn = False 
)

Construct the object for a data manager in the table given the name of the data manager or the column.

An exception is thrown if the data manager type is not the incremental storage manager.

virtual casacore::ROIncrementalStManAccessor::~ROIncrementalStManAccessor ( )
virtual
casacore::ROIncrementalStManAccessor::ROIncrementalStManAccessor ( const ROIncrementalStManAccessor that)

Copy constructor (reference semantics).

Member Function Documentation

uInt casacore::ROIncrementalStManAccessor::cacheSize ( ) const

Get the cache size (in buckets).

Bool casacore::ROIncrementalStManAccessor::checkBucketLayout ( uInt offendingCursor,
uInt offendingBucketStartRow,
uInt offendingBucketNrow,
uInt offendingBucketNr,
uInt offendingCol,
uInt offendingIndex,
uInt offendingRow,
uInt offendingPrevRow 
) const

Check that there are no repeated rowIds in the buckets comprising this ISM.

void casacore::ROIncrementalStManAccessor::clearCache ( )

Clear the caches used by the hypercubes in this storage manager.

It will flush the caches as needed and remove all buckets from them resulting in a possibly large drop in memory used.

ROIncrementalStManAccessor& casacore::ROIncrementalStManAccessor::operator= ( const ROIncrementalStManAccessor that)

Assignment (reference semantics).

void casacore::ROIncrementalStManAccessor::setCacheSize ( uInt  aSize,
Bool  canExceedNrBuckets = True 
)

Set the cache size (in buckets) to be used by the storage manager.

The cache size given in this way is not persistent. Only the cache size given to the constructors of the incremental storage managers, is persistent. If canExceedNrBuckets=True, the given cache size can be larger than the nr of buckets in the file. In this way the cache can be made large enough for a future file extnsion. Otherwise, it is limited to the actual number of buckets. This is useful if one wants the entire file to be cached.

void casacore::ROIncrementalStManAccessor::showBucketLayout ( ostream &  os) const

Show the layout of the buckets used by this storage manager.

void casacore::ROIncrementalStManAccessor::showIndexStatistics ( ostream &  os) const

Show the index used by this storage manager.

Member Data Documentation

ISMBase* casacore::ROIncrementalStManAccessor::dataManPtr_p
private

Definition at line 158 of file IncrStManAccessor.h.


The documentation for this class was generated from the following file: