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
|
/*! @page dump_formats Dump Formats
The @ref util_dump command produces a flat-text representation of a
table that can be loaded by @ref util_load. This page describes the
output formats of the @ref util_dump command.
@section dump_formats_json JSON dump format
JSON (<a href="http://www.json.org">JavaScript Object Notation</a>)
dump files use the standard JSON data-interchange format to specify
the objects, and may be interpreted by any JSON reader.
The format is a JSON object where each key is the URI passed to
WT_SESSION::create and the corresponding value is a JSON array of two
entries. The first entry in this array is a JSON object composed of
configuration information: the "config" key has the configuration
string used with WT_SESSION::create, the "colgroups" and "indices"
keys have values that are arrays of objects that are in turn composed
of configuration information. The second entry is a JSON array, with
each entry an object representing a row of data. If the columns were
named in the configuration string used with WT_SESSION::create, those
names are used for keys, otherwise predictable names (for example,
"key0", "value0", "value1") are generated. The values in this object
are the values for each column in the record.
Here is some sample output:
@code
{
"table:planets" : [
{
"config" : "columns=(id,name,distance),key_format=i,value_format=Si",
"colgroups" : [],
"indices" : [
{
"uri" : "index:planets:names",
"config" : "columns=(name),key_format=Si,source=\"file:astronomy.wt\",type=file"
}
]
},
[
{
"id" : 1,
"name" : "Mercury",
"distance" : 57910000
},
{
"id" : 2,
"name" : "Venus",
"distance" : 108200000
},
...
]
]
}
@endcode
@section dump_formats_text Text dump format
Text dump files have three parts, a prefix, a header and a body.
The dump prefix includes basic information about the dump including the
WiredTiger version that created the dump and the dump format. The dump
format consists of a line beginning with \c "Format=", and contains the
following information:
<table>
@hrow{String, Meaning}
@row{hex, the dumped data is in a hexadecimal dump format}
@row{print, the dumped data is in a printable format}
</table>
The dump header follows a single \c "Header" line in the file and
consists of paired key and value lines, where the key is the URI passed
to WT_SESSION::create and the value is corresponding configuration
string. The table or file can be recreated by calling
WT_SESSION::create for each pair of lines in the header.
The dump body follows a single \c "Data" line in the file and consists
of a text representation of the records in the table. Each record is a
represented by a pair of lines: the first line is the key and the second
line is the value. These lines are encoded in one of two formats: a
printable format and a hexadecimal format.
The printable format consists of literal printable characters, and
hexadecimal encoded non-printable characters. Encoded characters are
written as three separate characters: a backslash character followed by
two hexadecimal characters (first the high nibble and then the low
nibble). For example, a newline character in the ASCII character set
would be encoded as \c "\0a" and an escape character would be encoded
as \c "\1b". Backslash characters which do not precede a hexadecimal
encoding are paired, that is, the characters \c "\\" should be
interpreted as a single backslash character.
The hexadecimal format consists of encoded characters, where each
literal character is written as a pair of characters (first the
high-nibble and then the low-nibble). For example, "0a" would be an
ASCII newline character and "1b" would be an ASCII escape character.
Because the definition of "printable" may depend on the application's
locale, dump files in the printable output format may be less portable
than dump files in the hexadecimal output format.
*/
|
