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
202
203
204
205
206
207
|
/*-------------------------------------------------------------------------
*
* pg_logicalinspect.c
* Functions to inspect contents of PostgreSQL logical snapshots
*
* Copyright (c) 2024-2025, PostgreSQL Global Development Group
*
* IDENTIFICATION
* contrib/pg_logicalinspect/pg_logicalinspect.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "funcapi.h"
#include "replication/snapbuild_internal.h"
#include "utils/array.h"
#include "utils/builtins.h"
#include "utils/pg_lsn.h"
PG_MODULE_MAGIC_EXT(
.name = "pg_logicalinspect",
.version = PG_VERSION
);
PG_FUNCTION_INFO_V1(pg_get_logical_snapshot_meta);
PG_FUNCTION_INFO_V1(pg_get_logical_snapshot_info);
/* Return the description of SnapBuildState */
static const char *
get_snapbuild_state_desc(SnapBuildState state)
{
const char *stateDesc = "unknown state";
switch (state)
{
case SNAPBUILD_START:
stateDesc = "start";
break;
case SNAPBUILD_BUILDING_SNAPSHOT:
stateDesc = "building";
break;
case SNAPBUILD_FULL_SNAPSHOT:
stateDesc = "full";
break;
case SNAPBUILD_CONSISTENT:
stateDesc = "consistent";
break;
}
return stateDesc;
}
/*
* Extract the LSN from the given serialized snapshot file name.
*/
static XLogRecPtr
parse_snapshot_filename(const char *filename)
{
uint32 hi;
uint32 lo;
XLogRecPtr lsn;
char tmpfname[MAXPGPATH];
/*
* Extract the values to build the LSN.
*
* Note: Including ".snap" doesn't mean that sscanf() also does the format
* check including the suffix. The subsequent check validates if the given
* filename has the expected suffix.
*/
if (sscanf(filename, "%X-%X.snap", &hi, &lo) != 2)
goto parse_error;
/*
* Bring back the extracted LSN to the snapshot file format and compare it
* to the given filename. This check strictly checks if the given filename
* follows the format of the snapshot filename.
*/
sprintf(tmpfname, "%X-%X.snap", hi, lo);
if (strcmp(tmpfname, filename) != 0)
goto parse_error;
lsn = ((uint64) hi) << 32 | lo;
return lsn;
parse_error:
ereport(ERROR,
errmsg("invalid snapshot file name \"%s\"", filename));
return InvalidXLogRecPtr; /* keep compiler quiet */
}
/*
* Retrieve the logical snapshot file metadata.
*/
Datum
pg_get_logical_snapshot_meta(PG_FUNCTION_ARGS)
{
#define PG_GET_LOGICAL_SNAPSHOT_META_COLS 3
SnapBuildOnDisk ondisk;
HeapTuple tuple;
Datum values[PG_GET_LOGICAL_SNAPSHOT_META_COLS] = {0};
bool nulls[PG_GET_LOGICAL_SNAPSHOT_META_COLS] = {0};
TupleDesc tupdesc;
XLogRecPtr lsn;
int i = 0;
text *filename_t = PG_GETARG_TEXT_PP(0);
/* Build a tuple descriptor for our result type */
if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
elog(ERROR, "return type must be a row type");
lsn = parse_snapshot_filename(text_to_cstring(filename_t));
/* Validate and restore the snapshot to 'ondisk' */
SnapBuildRestoreSnapshot(&ondisk, lsn, CurrentMemoryContext, false);
values[i++] = UInt32GetDatum(ondisk.magic);
values[i++] = Int64GetDatum((int64) ondisk.checksum);
values[i++] = UInt32GetDatum(ondisk.version);
Assert(i == PG_GET_LOGICAL_SNAPSHOT_META_COLS);
tuple = heap_form_tuple(tupdesc, values, nulls);
PG_RETURN_DATUM(HeapTupleGetDatum(tuple));
#undef PG_GET_LOGICAL_SNAPSHOT_META_COLS
}
Datum
pg_get_logical_snapshot_info(PG_FUNCTION_ARGS)
{
#define PG_GET_LOGICAL_SNAPSHOT_INFO_COLS 14
SnapBuildOnDisk ondisk;
HeapTuple tuple;
Datum values[PG_GET_LOGICAL_SNAPSHOT_INFO_COLS] = {0};
bool nulls[PG_GET_LOGICAL_SNAPSHOT_INFO_COLS] = {0};
TupleDesc tupdesc;
XLogRecPtr lsn;
int i = 0;
text *filename_t = PG_GETARG_TEXT_PP(0);
/* Build a tuple descriptor for our result type */
if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
elog(ERROR, "return type must be a row type");
lsn = parse_snapshot_filename(text_to_cstring(filename_t));
/* Validate and restore the snapshot to 'ondisk' */
SnapBuildRestoreSnapshot(&ondisk, lsn, CurrentMemoryContext, false);
values[i++] = CStringGetTextDatum(get_snapbuild_state_desc(ondisk.builder.state));
values[i++] = TransactionIdGetDatum(ondisk.builder.xmin);
values[i++] = TransactionIdGetDatum(ondisk.builder.xmax);
values[i++] = LSNGetDatum(ondisk.builder.start_decoding_at);
values[i++] = LSNGetDatum(ondisk.builder.two_phase_at);
values[i++] = TransactionIdGetDatum(ondisk.builder.initial_xmin_horizon);
values[i++] = BoolGetDatum(ondisk.builder.building_full_snapshot);
values[i++] = BoolGetDatum(ondisk.builder.in_slot_creation);
values[i++] = LSNGetDatum(ondisk.builder.last_serialized_snapshot);
values[i++] = TransactionIdGetDatum(ondisk.builder.next_phase_at);
values[i++] = UInt32GetDatum(ondisk.builder.committed.xcnt);
if (ondisk.builder.committed.xcnt > 0)
{
Datum *arrayelems;
arrayelems = (Datum *) palloc(ondisk.builder.committed.xcnt * sizeof(Datum));
for (int j = 0; j < ondisk.builder.committed.xcnt; j++)
arrayelems[j] = TransactionIdGetDatum(ondisk.builder.committed.xip[j]);
values[i++] = PointerGetDatum(construct_array_builtin(arrayelems,
ondisk.builder.committed.xcnt,
XIDOID));
}
else
nulls[i++] = true;
values[i++] = UInt32GetDatum(ondisk.builder.catchange.xcnt);
if (ondisk.builder.catchange.xcnt > 0)
{
Datum *arrayelems;
arrayelems = (Datum *) palloc(ondisk.builder.catchange.xcnt * sizeof(Datum));
for (int j = 0; j < ondisk.builder.catchange.xcnt; j++)
arrayelems[j] = TransactionIdGetDatum(ondisk.builder.catchange.xip[j]);
values[i++] = PointerGetDatum(construct_array_builtin(arrayelems,
ondisk.builder.catchange.xcnt,
XIDOID));
}
else
nulls[i++] = true;
Assert(i == PG_GET_LOGICAL_SNAPSHOT_INFO_COLS);
tuple = heap_form_tuple(tupdesc, values, nulls);
PG_RETURN_DATUM(HeapTupleGetDatum(tuple));
#undef PG_GET_LOGICAL_SNAPSHOT_INFO_COLS
}
|
