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Commitd6061f8

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Improve pageinspect module
Now pageinspect can show data stored in the heap tuple.Nikolay Shaplov
1 parent13b30c1 commitd6061f8

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5 files changed

+411
-19
lines changed

5 files changed

+411
-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
ifdefUSE_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+
staticbits8*
67+
text_to_bits(char*str,intlen)
68+
{
69+
bits8*bits;
70+
intoff=0;
71+
charbyte=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+
returnbits;
94+
}
95+
5796
/*
5897
* heap_page_items
5998
*
@@ -122,8 +161,8 @@ heap_page_items(PG_FUNCTION_ARGS)
122161
HeapTupleresultTuple;
123162
Datumresult;
124163
ItemIdid;
125-
Datumvalues[13];
126-
boolnulls[13];
164+
Datumvalues[14];
165+
boolnulls[14];
127166
uint16lp_offset;
128167
uint16lp_flags;
129168
uint16lp_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-
HeapTupleHeadertuphdr;
157-
intbits_len;
195+
HeapTupleHeadertuphdr;
196+
bytea*tuple_data_bytea;
197+
inttuple_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+
intbits_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
inti;
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+
staticDatum
285+
tuple_data_split_internal(Oidrelid,char*tupdata,
286+
uint16tupdata_len,uint16t_infomask,
287+
uint16t_infomask2,bits8*t_bits,
288+
booldo_detoast)
289+
{
290+
ArrayBuildState*raw_attrs;
291+
intnattrs;
292+
inti;
293+
intoff=0;
294+
Relationrel;
295+
TupleDesctupdesc;
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_attributeattr;
313+
boolis_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+
intlen;
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+
returnmakeArrayResult(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+
Oidrelid;
400+
bytea*raw_data;
401+
uint16t_infomask;
402+
uint16t_infomask2;
403+
char*t_bits_str;
404+
booldo_detoast= false;
405+
bits8*t_bits=NULL;
406+
Datumres;
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+
intbits_str_len;
433+
intbits_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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