casacore
StorageOption.h
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1//# StorageOption.h: Options defining how table files are organized
2//# Copyright (C) 2014
3//# Associated Universities, Inc. Washington DC, USA.
4//#
5//# This library is free software; you can redistribute it and/or modify it
6//# under the terms of the GNU Library General Public License as published by
7//# the Free Software Foundation; either version 2 of the License, or (at your
8//# option) any later version.
9//#
10//# This library is distributed in the hope that it will be useful, but WITHOUT
11//# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12//# FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public
13//# License for more details.
14//#
15//# You should have receied a copy of the GNU Library General Public License
16//# along with this library; if not, write to the Free Software Foundation,
17//# Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.
18//#
19//# Correspondence concerning AIPS++ should be addressed as follows:
20//# Internet email: aips2-request@nrao.edu.
21//# Postal address: AIPS++ Project Office
22//# National Radio Astronomy Observatory
23//# 520 Edgemont Road
24//# Charlottesville, VA 22903-2475 USA
25//#
26//# $Id: StorageOption.h 20859 2010-02-03 13:14:15Z gervandiepen $
27
28#ifndef TABLES_STORAGEOPTION_H
29#define TABLES_STORAGEOPTION_H
30
31
32//# Includes
33#include <casacore/casa/aips.h>
34
35namespace casacore { //# NAMESPACE CASACORE - BEGIN
36
37// <summary>
38// Options defining how table files are organized
39// </summary>
40
41// <use visibility=export>
42
43// <reviewed reviewer="TPPR" date="08.11.94" tests="tTable.cc">
44// </reviewed>
45
46// <synopsis>
47// This class can be used to define how the files of a table are organized.
48// There are two ways:
49// <ol>
50// <li> The old way where each storage manager has its own file(s).
51// <li> Using MultiFile that storage managers can use to combine about all
52// table files in a single file. This mode is particularly useful
53// for new file systems (like Lustre) requiring large block sizes.
54// <br>The block size to be used in a MultiFile can be defined in
55// this class. Default is 4 MByte.
56// <li> Using MultiHDF5 which behaves similar to MultiFile but uses an
57// HDF5 file instead of a regular file. Note that it requires that
58// support for HDF5 has been used in the build system.
59// </ol>
60// It is possible to specify the storage type and block size using aipsrc.
61// The aipsrc variables are:
62// <ul>
63// <li> <src>table.storage.option</src>. The (case-insensitive) value can be
64// 'multifile' or 'multihdf5'.
65// Another value means the old way (separate files).
66// <li> <src>table.storage.blocksize</src> gives the default blocksize to be
67// used for the multifile and multihdf5 option.
68// <li> <src>table.storage.odirect</src> can be true or false. It tells if the
69// O_DIRECT option has to be used to let the kernel bypass its filecache
70// for more predictable I/O behaviour. It's only used for MultiFile and
71// only if the OS supports O_DIRECT.
72// </ul>
73// </synopsis>
74
75
77 {
78 public:
79 // Define the possible options how table files are organized.
80 enum Option {
81 // Let storage managers use a combined MultiFile.
83 // Let storage managers use a combined MultiHDF5.
85 // Let storage managers use separate files.
87 // Use default (currently SepFile).
89 // Use as defined in the aipsrc file.
90 Aipsrc
91 };
92
93 // Create an option object.
94 // The parameter values are described in the synopsis.
95 // The blocksize has to be given in bytes.
96 // A size value -2 means reading that size from the aipsrc file.
97 // A size value -1 means use the default of 4*1024*1024.
98 // <br>useODirect<0 means reading the option from the aipsrc file.
99 // It is only set if the OS supports O_DIRECT.
101
102 // Fill the option in case Aipsrc or Default was given.
103 // It is done as explained in the synopsis.
105
106 // Get the option.
108 { return itsOption; }
109
110 // Set the option.
112 { itsOption = option; }
113
114 // Get the block size (in bytes).
116 { return itsBlockSize; }
117
118 // Set the block size (in bytes).
121
122 // Get the O_DIRECT option.
124 { return itsUseODirect; }
125
126 // Set the O_DIRECT option.
127 // It is only set if the OS supports O_DIRECT.
129
130 private:
135 };
136
137} //# NAMESPACE CASACORE - END
138
139#endif
StorageOption(Option option=Aipsrc, Int blockSize=-2, Int useODirect=-3)
Create an option object.
void fillOption()
Fill the option in case Aipsrc or Default was given.
void setOption(Option option)
Set the option.
Bool useODirect() const
Get the O_DIRECT option.
Option
Define the possible options how table files are organized.
Definition: StorageOption.h:80
@ MultiFile
Let storage managers use a combined MultiFile.
Definition: StorageOption.h:82
@ SepFile
Let storage managers use separate files.
Definition: StorageOption.h:86
@ MultiHDF5
Let storage managers use a combined MultiHDF5.
Definition: StorageOption.h:84
@ Default
Use default (currently SepFile).
Definition: StorageOption.h:88
uInt blockSize() const
Get the block size (in bytes).
void setBlockSize(Int blockSize)
Set the block size (in bytes).
void setUseODirect(Bool useODirect)
Set the O_DIRECT option.
Option option() const
Get the option.
this file contains all the compiler specific defines
Definition: mainpage.dox:28
unsigned int uInt
Definition: aipstype.h:51
int Int
Definition: aipstype.h:50
bool Bool
Define the standard types used by Casacore.
Definition: aipstype.h:42