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
|
/******************************************************
Caching of externally stored column prefixes
(c) 2006 Innobase Oy
Created September 2006 Marko Makela
*******************************************************/
#include "rem0types.h"
#include "btr0types.h"
/************************************************************************
Looks up a column prefix of an externally stored column. */
UNIV_INLINE
const byte*
row_ext_lookup_ith(
/*===============*/
/* out: column prefix, or NULL if
the column is not stored externally,
or pointer to field_ref_zero
if the BLOB pointer is unset */
const row_ext_t* ext, /* in/out: column prefix cache */
ulint i, /* in: index of ext->ext[] */
ulint* len) /* out: length of prefix, in bytes,
at most REC_MAX_INDEX_COL_LEN */
{
ut_ad(ext);
ut_ad(len);
ut_ad(i < ext->n_ext);
*len = ext->len[i];
if (UNIV_UNLIKELY(*len == 0)) {
/* The BLOB could not be fetched to the cache. */
return(field_ref_zero);
} else {
return(ext->buf + i * REC_MAX_INDEX_COL_LEN);
}
}
/************************************************************************
Looks up a column prefix of an externally stored column. */
UNIV_INLINE
const byte*
row_ext_lookup(
/*===========*/
/* out: column prefix, or NULL if
the column is not stored externally,
or pointer to field_ref_zero
if the BLOB pointer is unset */
const row_ext_t* ext, /* in: column prefix cache */
ulint col, /* in: column number in the InnoDB
table object, as reported by
dict_col_get_no(); NOT relative to the
records in the clustered index */
ulint* len) /* out: length of prefix, in bytes,
at most REC_MAX_INDEX_COL_LEN */
{
ulint i;
ut_ad(ext);
ut_ad(len);
for (i = 0; i < ext->n_ext; i++) {
if (col == ext->ext[i]) {
return(row_ext_lookup_ith(ext, i, len));
}
}
return(NULL);
}
|