blob: 46e5ce5b6857fd5546306d199c59bdb34d3aed96 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
|
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>DB_ENV->set_blob_threshold()</title>
<link rel="stylesheet" href="apiReference.css" type="text/css" />
<meta name="generator" content="DocBook XSL Stylesheets V1.73.2" />
<link rel="start" href="index.html" title="Berkeley DB C API Reference" />
<link rel="up" href="blob.html" title="Chapter 13. Binary Large Objects" />
<link rel="prev" href="envset_blob_dir.html" title="DB_ENV->set_blob_dir()" />
<link rel="next" href="utilities.html" title="Appendix A. Berkeley DB Command Line Utilities" />
</head>
<body>
<div xmlns="" class="navheader">
<div class="libver">
<p>Library Version 12.1.6.1</p>
</div>
<table width="100%" summary="Navigation header">
<tr>
<th colspan="3" align="center">DB_ENV->set_blob_threshold()</th>
</tr>
<tr>
<td width="20%" align="left"><a accesskey="p" href="envset_blob_dir.html">Prev</a> </td>
<th width="60%" align="center">Chapter 13.
Binary Large Objects
</th>
<td width="20%" align="right"> <a accesskey="n" href="utilities.html">Next</a></td>
</tr>
</table>
<hr />
</div>
<div class="sect1" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h2 class="title" style="clear: both"><a id="envset_blob_threshold"></a>DB_ENV->set_blob_threshold()</h2>
</div>
</div>
</div>
<pre class="programlisting">#include <db.h>
int
DB_ENV->set_blob_threshold(DB_ENV *dbenv, u_int32_t bytes,
u_int32_t flags); </pre>
<p>
The <code class="methodname">DB_ENV->set_blob_threshold()</code> method sets
a default size for the environment which is used to determine when
a data item will be stored as a BLOB. Data items sized less than
this threshold are stored as normal data within the database. Data
items larger than this size are stored on-disk in a subdirectory
set aside for the purpose.
</p>
<p>
If this threshold value is set to <code class="literal">0</code>, then BLOB
support is turned off by default for databases created in the
environment. If this method is never called, then the default BLOB
threshold is <code class="literal">0</code>.
</p>
<p>
This method only sets the default BLOB threshold for the
environment. The BLOB threshold can be set for individual
databases created within the environment using
<a class="xref" href="set_blob_threshold.html" title="DB->set_blob_threshold()">DB->set_blob_threshold()</a>.
</p>
<p>
It is illegal to set a BLOB threshold if replication is enabled
for the environment. That is, if the
<a class="link" href="envopen.html#envopen_DB_INIT_REP">DB_INIT_REP</a>
flag is specified to <a class="xref" href="envopen.html" title="DB_ENV->open()">DB_ENV->open()</a>.
</p>
<p>
This method configures operations performed using the specified
<a class="link" href="env.html" title="Chapter 5. The DB_ENV Handle">DB_ENV</a> handle, not all operations
performed on the underlying database environment.
</p>
<p>
You may call this method at any time after the DB_ENV handle
has been created.
</p>
<p>
Unless otherwise specified, the
<code class="methodname">DB_ENV->set_blob_threshold()</code> <span>
<span>
method returns a non-zero error value on failure and 0 on success.
</span>
</span>
</p>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="idp4903912"></a>Parameters</h3>
</div>
</div>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="idp4903264"></a>bytes</h4>
</div>
</div>
</div>
<p>
The <span class="bold"><strong>bytes</strong></span> parameter
identifies the threshold size, in bytes, beyond which a
data item is stored as a BLOB.
</p>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="idp4892472"></a>flags</h4>
</div>
</div>
</div>
<p>
The <span class="bold"><strong>flags</strong></span> parameter must be set to 0.
</p>
</div>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="idp4904992"></a>Errors</h3>
</div>
</div>
</div>
<p>
The <code class="methodname">DB_ENV->set_blob_threshold()</code> <span>
<span>
method may fail and return one of the following non-zero errors:
</span>
</span>
</p>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="idp4903048"></a>EINVAL</h4>
</div>
</div>
</div>
<p>
If an invalid flag or parameter was specified.
</p>
</div>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="idp4912432"></a>Class</h3>
</div>
</div>
</div>
<p>
<a class="link" href="env.html" title="Chapter 5. The DB_ENV Handle">DB_ENV</a>
</p>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="idp4913624"></a>See Also</h3>
</div>
</div>
</div>
<p>
<a class="xref" href="blob.html#bloblist" title="BLOBs and Related Methods">BLOBs and Related Methods</a>
</p>
</div>
</div>
<div class="navfooter">
<hr />
<table width="100%" summary="Navigation footer">
<tr>
<td width="40%" align="left"><a accesskey="p" href="envset_blob_dir.html">Prev</a> </td>
<td width="20%" align="center">
<a accesskey="u" href="blob.html">Up</a>
</td>
<td width="40%" align="right"> <a accesskey="n" href="utilities.html">Next</a></td>
</tr>
<tr>
<td width="40%" align="left" valign="top">DB_ENV->set_blob_dir() </td>
<td width="20%" align="center">
<a accesskey="h" href="index.html">Home</a>
</td>
<td width="40%" align="right" valign="top"> Appendix A.
Berkeley DB Command Line Utilities
</td>
</tr>
</table>
</div>
</body>
</html>
|
