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Nikolay Shaplovvbwagner
Nikolay Shaplov
authored and
vbwagner
committed
Add patch that allows to view tuple raw data in pageinspect the way it was commited in master 9.6
in d6061f8 and 0271e27 original commit message: Improve pageinspect module Now pageinspect can show data stored in the heap tuple. Nikolay Shaplov
1 parent c744982 commit 68f8b23

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6 files changed

+529
-19
lines changed

6 files changed

+529
-19
lines changed

‎contrib/pageinspect/Makefile

Lines changed: 3 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -5,9 +5,9 @@ OBJS = rawpage.o heapfuncs.o btreefuncs.o fsmfuncs.o \
55
brinfuncs.o ginfuncs.o $(WIN32RES)
66

77
EXTENSION = pageinspect
8-
DATA = pageinspect--1.3.sql pageinspect--1.2--1.3.sql \
9-
pageinspect--1.1--1.2.sql pageinspect--1.0--1.1.sql \
10-
pageinspect--unpackaged--1.0.sql
8+
DATA = pageinspect--1.4.sql pageinspect--1.3--1.4.sql \
9+
pageinspect--1.2--1.3.sql pageinspect--1.1--1.2.sql \
10+
pageinspect--1.0--1.1.sql pageinspect--unpackaged--1.0.sql
1111
PGFILEDESC = "pageinspect - functions to inspect contents of database pages"
1212

1313
ifdef USE_PGXS

‎contrib/pageinspect/heapfuncs.c

Lines changed: 261 additions & 10 deletions
Original file line numberDiff line numberDiff line change
@@ -27,8 +27,11 @@
2727

2828
#include "access/htup_details.h"
2929
#include "funcapi.h"
30-
#include "utils/builtins.h"
30+
#include "catalog/pg_type.h"
3131
#include "miscadmin.h"
32+
#include "utils/array.h"
33+
#include "utils/builtins.h"
34+
#include "utils/rel.h"
3235

3336

3437
/*
@@ -54,6 +57,42 @@ bits_to_text(bits8 *bits, int len)
5457
}
5558

5659

60+
/*
61+
* text_to_bits
62+
*
63+
* Converts a c-string representation of bits into a bits8-array. This is
64+
* the reverse operation of previous routine.
65+
*/
66+
static bits8 *
67+
text_to_bits(char *str, int len)
68+
{
69+
bits8 *bits;
70+
int off = 0;
71+
char byte = 0;
72+
73+
bits = palloc(len + 1);
74+
75+
while (off < len)
76+
{
77+
if (off % 8 == 0)
78+
byte = 0;
79+
80+
if ((str[off] == '0') || (str[off] == '1'))
81+
byte = byte | ((str[off] - '0') << off % 8);
82+
else
83+
ereport(ERROR,
84+
(errcode(ERRCODE_DATA_CORRUPTED),
85+
errmsg("illegal character '%c' in t_bits string", str[off])));
86+
87+
if (off % 8 == 7)
88+
bits[off / 8] = byte;
89+
90+
off++;
91+
}
92+
93+
return bits;
94+
}
95+
5796
/*
5897
* heap_page_items
5998
*
@@ -122,8 +161,8 @@ heap_page_items(PG_FUNCTION_ARGS)
122161
HeapTuple resultTuple;
123162
Datum result;
124163
ItemId id;
125-
Datum values[13];
126-
bool nulls[13];
164+
Datum values[14];
165+
bool nulls[14];
127166
uint16 lp_offset;
128167
uint16 lp_flags;
129168
uint16 lp_len;
@@ -153,21 +192,31 @@ heap_page_items(PG_FUNCTION_ARGS)
153192
lp_offset == MAXALIGN(lp_offset) &&
154193
lp_offset + lp_len <= raw_page_size)
155194
{
156-
HeapTupleHeader tuphdr;
157-
int bits_len;
195+
HeapTupleHeader tuphdr;
196+
bytea *tuple_data_bytea;
197+
int tuple_data_len;
158198

159199
/* Extract information from the tuple header */
160200

161201
tuphdr = (HeapTupleHeader) PageGetItem(page, id);
162202

163203
values[4] = UInt32GetDatum(HeapTupleHeaderGetRawXmin(tuphdr));
164204
values[5] = UInt32GetDatum(HeapTupleHeaderGetRawXmax(tuphdr));
165-
values[6] = UInt32GetDatum(HeapTupleHeaderGetRawCommandId(tuphdr)); /* shared with xvac */
205+
/* shared with xvac */
206+
values[6] = UInt32GetDatum(HeapTupleHeaderGetRawCommandId(tuphdr));
166207
values[7] = PointerGetDatum(&tuphdr->t_ctid);
167208
values[8] = UInt32GetDatum(tuphdr->t_infomask2);
168209
values[9] = UInt32GetDatum(tuphdr->t_infomask);
169210
values[10] = UInt8GetDatum(tuphdr->t_hoff);
170211

212+
/* Copy raw tuple data into bytea attribute */
213+
tuple_data_len = lp_len - tuphdr->t_hoff;
214+
tuple_data_bytea = (bytea *) palloc(tuple_data_len + VARHDRSZ);
215+
SET_VARSIZE(tuple_data_bytea, tuple_data_len + VARHDRSZ);
216+
memcpy(VARDATA(tuple_data_bytea), (char *) tuphdr + tuphdr->t_hoff,
217+
tuple_data_len);
218+
values[13] = PointerGetDatum(tuple_data_bytea);
219+
171220
/*
172221
* We already checked that the item is completely within the raw
173222
* page passed to us, with the length given in the line pointer.
@@ -180,11 +229,11 @@ heap_page_items(PG_FUNCTION_ARGS)
180229
{
181230
if (tuphdr->t_infomask & HEAP_HASNULL)
182231
{
183-
bits_len = tuphdr->t_hoff -
184-
offsetof(HeapTupleHeaderData, t_bits);
232+
int bits_len =
233+
((tuphdr->t_infomask2 & HEAP_NATTS_MASK) / 8 + 1) * 8;
185234

186235
values[11] = CStringGetTextDatum(
187-
bits_to_text(tuphdr->t_bits, bits_len * 8));
236+
bits_to_text(tuphdr->t_bits, bits_len));
188237
}
189238
else
190239
nulls[11] = true;
@@ -208,7 +257,7 @@ heap_page_items(PG_FUNCTION_ARGS)
208257
*/
209258
int i;
210259

211-
for (i = 4; i <= 12; i++)
260+
for (i = 4; i <= 13; i++)
212261
nulls[i] = true;
213262
}
214263

@@ -223,3 +272,205 @@ heap_page_items(PG_FUNCTION_ARGS)
223272
else
224273
SRF_RETURN_DONE(fctx);
225274
}
275+
276+
/*
277+
* tuple_data_split_internal
278+
*
279+
* Split raw tuple data taken directly from a page into an array of bytea
280+
* elements. This routine does a lookup on NULL values and creates array
281+
* elements accordindly. This is a reimplementation of nocachegetattr()
282+
* in heaptuple.c simplified for educational purposes.
283+
*/
284+
static Datum
285+
tuple_data_split_internal(Oid relid, char *tupdata,
286+
uint16 tupdata_len, uint16 t_infomask,
287+
uint16 t_infomask2, bits8 *t_bits,
288+
bool do_detoast)
289+
{
290+
ArrayBuildState *raw_attrs;
291+
int nattrs;
292+
int i;
293+
int off = 0;
294+
Relation rel;
295+
TupleDesc tupdesc;
296+
297+
/* Get tuple descriptor from relation OID */
298+
rel = relation_open(relid, NoLock);
299+
tupdesc = CreateTupleDescCopyConstr(rel->rd_att);
300+
relation_close(rel, NoLock);
301+
302+
raw_attrs = initArrayResult(BYTEAOID, CurrentMemoryContext, false);
303+
nattrs = tupdesc->natts;
304+
305+
if (nattrs < (t_infomask2 & HEAP_NATTS_MASK))
306+
ereport(ERROR,
307+
(errcode(ERRCODE_DATA_CORRUPTED),
308+
errmsg("number of attributes in tuple header is greater than number of attributes in tuple descriptor")));
309+
310+
for (i = 0; i < nattrs; i++)
311+
{
312+
Form_pg_attribute attr;
313+
bool is_null;
314+
bytea *attr_data = NULL;
315+
316+
attr = tupdesc->attrs[i];
317+
is_null = (t_infomask & HEAP_HASNULL) && att_isnull(i, t_bits);
318+
319+
/*
320+
* Tuple header can specify less attributes than tuple descriptor
321+
* as ALTER TABLE ADD COLUMN without DEFAULT keyword does not
322+
* actually change tuples in pages, so attributes with numbers greater
323+
* than (t_infomask2 & HEAP_NATTS_MASK) should be treated as NULL.
324+
*/
325+
if (i >= (t_infomask2 & HEAP_NATTS_MASK))
326+
is_null = true;
327+
328+
if (!is_null)
329+
{
330+
int len;
331+
332+
if (attr->attlen == -1)
333+
{
334+
off = att_align_pointer(off, tupdesc->attrs[i]->attalign, -1,
335+
tupdata + off);
336+
/*
337+
* As VARSIZE_ANY throws an exception if it can't properly
338+
* detect the type of external storage in macros VARTAG_SIZE,
339+
* this check is repeated to have a nicer error handling.
340+
*/
341+
if (VARATT_IS_EXTERNAL(tupdata + off) &&
342+
!VARATT_IS_EXTERNAL_ONDISK(tupdata + off) &&
343+
!VARATT_IS_EXTERNAL_INDIRECT(tupdata + off))
344+
ereport(ERROR,
345+
(errcode(ERRCODE_DATA_CORRUPTED),
346+
errmsg("first byte of varlena attribute is incorrect for attribute %d", i)));
347+
348+
len = VARSIZE_ANY(tupdata + off);
349+
}
350+
else
351+
{
352+
off = att_align_nominal(off, tupdesc->attrs[i]->attalign);
353+
len = attr->attlen;
354+
}
355+
356+
if (tupdata_len < off + len)
357+
ereport(ERROR,
358+
(errcode(ERRCODE_DATA_CORRUPTED),
359+
errmsg("unexpected end of tuple data")));
360+
361+
if (attr->attlen == -1 && do_detoast)
362+
attr_data = DatumGetByteaPCopy(tupdata + off);
363+
else
364+
{
365+
attr_data = (bytea *) palloc(len + VARHDRSZ);
366+
SET_VARSIZE(attr_data, len + VARHDRSZ);
367+
memcpy(VARDATA(attr_data), tupdata + off, len);
368+
}
369+
370+
off = att_addlength_pointer(off, tupdesc->attrs[i]->attlen,
371+
tupdata + off);
372+
}
373+
374+
raw_attrs = accumArrayResult(raw_attrs, PointerGetDatum(attr_data),
375+
is_null, BYTEAOID, CurrentMemoryContext);
376+
if (attr_data)
377+
pfree(attr_data);
378+
}
379+
380+
if (tupdata_len != off)
381+
ereport(ERROR,
382+
(errcode(ERRCODE_DATA_CORRUPTED),
383+
errmsg("end of tuple reached without looking at all its data")));
384+
385+
return makeArrayResult(raw_attrs, CurrentMemoryContext);
386+
}
387+
388+
/*
389+
* tuple_data_split
390+
*
391+
* Split raw tuple data taken directly from page into distinct elements
392+
* taking into account null values.
393+
*/
394+
PG_FUNCTION_INFO_V1(tuple_data_split);
395+
396+
Datum
397+
tuple_data_split(PG_FUNCTION_ARGS)
398+
{
399+
Oid relid;
400+
bytea *raw_data;
401+
uint16 t_infomask;
402+
uint16 t_infomask2;
403+
char *t_bits_str;
404+
bool do_detoast = false;
405+
bits8 *t_bits = NULL;
406+
Datum res;
407+
408+
relid = PG_GETARG_OID(0);
409+
raw_data = PG_ARGISNULL(1) ? NULL : PG_GETARG_BYTEA_P(1);
410+
t_infomask = PG_GETARG_INT16(2);
411+
t_infomask2 = PG_GETARG_INT16(3);
412+
t_bits_str = PG_ARGISNULL(4) ? NULL :
413+
text_to_cstring(PG_GETARG_TEXT_PP(4));
414+
415+
if (PG_NARGS() >= 6)
416+
do_detoast = PG_GETARG_BOOL(5);
417+
418+
if (!superuser())
419+
ereport(ERROR,
420+
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
421+
errmsg("must be superuser to use raw page functions")));
422+
423+
if (!raw_data)
424+
PG_RETURN_NULL();
425+
426+
/*
427+
* Convert t_bits string back to the bits8 array as represented in the
428+
* tuple header.
429+
*/
430+
if (t_infomask & HEAP_HASNULL)
431+
{
432+
int bits_str_len;
433+
int bits_len;
434+
435+
bits_len = (t_infomask2 & HEAP_NATTS_MASK) / 8 + 1;
436+
if (!t_bits_str)
437+
ereport(ERROR,
438+
(errcode(ERRCODE_DATA_CORRUPTED),
439+
errmsg("argument of t_bits is null, but it is expected to be null and %i character long",
440+
bits_len * 8)));
441+
442+
bits_str_len = strlen(t_bits_str);
443+
if ((bits_str_len % 8) != 0)
444+
ereport(ERROR,
445+
(errcode(ERRCODE_DATA_CORRUPTED),
446+
errmsg("length of t_bits is not a multiple of eight")));
447+
448+
if (bits_len * 8 != bits_str_len)
449+
ereport(ERROR,
450+
(errcode(ERRCODE_DATA_CORRUPTED),
451+
errmsg("unexpected length of t_bits %u, expected %i",
452+
bits_str_len, bits_len * 8)));
453+
454+
/* do the conversion */
455+
t_bits = text_to_bits(t_bits_str, bits_str_len);
456+
}
457+
else
458+
{
459+
if (t_bits_str)
460+
ereport(ERROR,
461+
(errcode(ERRCODE_DATA_CORRUPTED),
462+
errmsg("t_bits string is expected to be NULL, but instead it is %lu bytes length",
463+
strlen(t_bits_str))));
464+
}
465+
466+
/* Split tuple data */
467+
res = tuple_data_split_internal(relid, (char *) raw_data + VARHDRSZ,
468+
VARSIZE(raw_data) - VARHDRSZ,
469+
t_infomask, t_infomask2, t_bits,
470+
do_detoast);
471+
472+
if (t_bits)
473+
pfree(t_bits);
474+
475+
PG_RETURN_ARRAYTYPE_P(res);
476+
}

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