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Commitdcb2bda

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Improve plpgsql's ability to cope with rowtypes containing dropped columns,
by supporting conversions in places that used to demand exact rowtype match.Since this issue is certain to come up elsewhere (in fact, already has,in ExecEvalConvertRowtype), factor out the support code into new corefunctions for tuple conversion. I chose to put these in a new sourcefile since heaptuple.c is already overly long.Heavily revised version of a patch by Pavel Stehule.
1 parent4000170 commitdcb2bda

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9 files changed

+545
-152
lines changed

9 files changed

+545
-152
lines changed

‎src/backend/access/common/Makefile

Lines changed: 3 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -4,14 +4,15 @@
44
# Makefile for access/common
55
#
66
# IDENTIFICATION
7-
# $PostgreSQL: pgsql/src/backend/access/common/Makefile,v 1.25 2008/02/19 11:49:12 petere Exp $
7+
# $PostgreSQL: pgsql/src/backend/access/common/Makefile,v 1.26 2009/08/06 20:44:31 tgl Exp $
88
#
99
#-------------------------------------------------------------------------
1010

1111
subdir = src/backend/access/common
1212
top_builddir = ../../../..
1313
include$(top_builddir)/src/Makefile.global
1414

15-
OBJS = heaptuple.o indextuple.o printtup.o reloptions.o scankey.o tupdesc.o
15+
OBJS = heaptuple.o indextuple.o printtup.o reloptions.o scankey.o\
16+
tupconvert.o tupdesc.o
1617

1718
include$(top_srcdir)/src/backend/common.mk
Lines changed: 343 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,343 @@
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/*-------------------------------------------------------------------------
2+
*
3+
* tupconvert.c
4+
* Tuple conversion support.
5+
*
6+
* These functions provide conversion between rowtypes that are logically
7+
* equivalent but might have columns in a different order or different sets
8+
* of dropped columns. There is some overlap of functionality with the
9+
* executor's "junkfilter" routines, but these functions work on bare
10+
* HeapTuples rather than TupleTableSlots.
11+
*
12+
* Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
13+
* Portions Copyright (c) 1994, Regents of the University of California
14+
*
15+
*
16+
* IDENTIFICATION
17+
* $PostgreSQL: pgsql/src/backend/access/common/tupconvert.c,v 1.1 2009/08/06 20:44:31 tgl Exp $
18+
*
19+
*-------------------------------------------------------------------------
20+
*/
21+
#include"postgres.h"
22+
23+
#include"access/tupconvert.h"
24+
#include"utils/builtins.h"
25+
26+
27+
/*
28+
* The conversion setup routines have the following common API:
29+
*
30+
* The setup routine checks whether the given source and destination tuple
31+
* descriptors are logically compatible. If not, it throws an error.
32+
* If so, it returns NULL if they are physically compatible (ie, no conversion
33+
* is needed), else a TupleConversionMap that can be used by do_convert_tuple
34+
* to perform the conversion.
35+
*
36+
* The TupleConversionMap, if needed, is palloc'd in the caller's memory
37+
* context. Also, the given tuple descriptors are referenced by the map,
38+
* so they must survive as long as the map is needed.
39+
*
40+
* The caller must supply a suitable primary error message to be used if
41+
* a compatibility error is thrown. Recommended coding practice is to use
42+
* gettext_noop() on this string, so that it is translatable but won't
43+
* actually be translated unless the error gets thrown.
44+
*
45+
*
46+
* Implementation notes:
47+
*
48+
* The key component of a TupleConversionMap is an attrMap[] array with
49+
* one entry per output column. This entry contains the 1-based index of
50+
* the corresponding input column, or zero to force a NULL value (for
51+
* a dropped output column). The TupleConversionMap also contains workspace
52+
* arrays.
53+
*/
54+
55+
56+
/*
57+
* Set up for tuple conversion, matching input and output columns by
58+
* position. (Dropped columns are ignored in both input and output.)
59+
*
60+
* Note: the errdetail messages speak of indesc as the "returned" rowtype,
61+
* outdesc as the "expected" rowtype. This is okay for current uses but
62+
* might need generalization in future.
63+
*/
64+
TupleConversionMap*
65+
convert_tuples_by_position(TupleDescindesc,
66+
TupleDescoutdesc,
67+
constchar*msg)
68+
{
69+
TupleConversionMap*map;
70+
AttrNumber*attrMap;
71+
intnincols;
72+
intnoutcols;
73+
intn;
74+
inti;
75+
intj;
76+
boolsame;
77+
78+
/* Verify compatibility and prepare attribute-number map */
79+
n=outdesc->natts;
80+
attrMap= (AttrNumber*)palloc0(n*sizeof(AttrNumber));
81+
j=0;/* j is next physical input attribute */
82+
nincols=noutcols=0;/* these count non-dropped attributes */
83+
same= true;
84+
for (i=0;i<n;i++)
85+
{
86+
Form_pg_attributeatt=outdesc->attrs[i];
87+
Oidatttypid;
88+
int32atttypmod;
89+
90+
if (att->attisdropped)
91+
continue;/* attrMap[i] is already 0 */
92+
noutcols++;
93+
atttypid=att->atttypid;
94+
atttypmod=att->atttypmod;
95+
for (;j<indesc->natts;j++)
96+
{
97+
att=indesc->attrs[j];
98+
if (att->attisdropped)
99+
continue;
100+
nincols++;
101+
/* Found matching column, check type */
102+
if (atttypid!=att->atttypid||
103+
(atttypmod!=att->atttypmod&&atttypmod >=0))
104+
ereport(ERROR,
105+
(errcode(ERRCODE_DATATYPE_MISMATCH),
106+
errmsg_internal("%s",_(msg)),
107+
errdetail("Returned type %s does not match expected type %s in column %d.",
108+
format_type_with_typemod(att->atttypid,
109+
att->atttypmod),
110+
format_type_with_typemod(atttypid,
111+
atttypmod),
112+
noutcols)));
113+
attrMap[i]= (AttrNumber) (j+1);
114+
j++;
115+
break;
116+
}
117+
if (attrMap[i]==0)
118+
same= false;/* we'll complain below */
119+
}
120+
121+
/* Check for unused input columns */
122+
for (;j<indesc->natts;j++)
123+
{
124+
if (indesc->attrs[j]->attisdropped)
125+
continue;
126+
nincols++;
127+
same= false;/* we'll complain below */
128+
}
129+
130+
/* Report column count mismatch using the non-dropped-column counts */
131+
if (!same)
132+
ereport(ERROR,
133+
(errcode(ERRCODE_DATATYPE_MISMATCH),
134+
errmsg_internal("%s",_(msg)),
135+
errdetail("Number of returned columns (%d) does not match "
136+
"expected column count (%d).",
137+
nincols,noutcols)));
138+
139+
/*
140+
* Check to see if the map is one-to-one and the tuple types are the
141+
* same. (We check the latter because if they're not, we want to do
142+
* conversion to inject the right OID into the tuple datum.)
143+
*/
144+
if (indesc->natts==outdesc->natts&&
145+
indesc->tdtypeid==outdesc->tdtypeid)
146+
{
147+
for (i=0;i<n;i++)
148+
{
149+
if (attrMap[i]!= (i+1))
150+
{
151+
same= false;
152+
break;
153+
}
154+
}
155+
}
156+
else
157+
same= false;
158+
159+
if (same)
160+
{
161+
/* Runtime conversion is not needed */
162+
pfree(attrMap);
163+
returnNULL;
164+
}
165+
166+
/* Prepare the map structure */
167+
map= (TupleConversionMap*)palloc(sizeof(TupleConversionMap));
168+
map->indesc=indesc;
169+
map->outdesc=outdesc;
170+
map->attrMap=attrMap;
171+
/* preallocate workspace for Datum arrays */
172+
map->outvalues= (Datum*)palloc(n*sizeof(Datum));
173+
map->outisnull= (bool*)palloc(n*sizeof(bool));
174+
n=indesc->natts+1;/* +1 for NULL */
175+
map->invalues= (Datum*)palloc(n*sizeof(Datum));
176+
map->inisnull= (bool*)palloc(n*sizeof(bool));
177+
map->invalues[0]= (Datum)0;/* set up the NULL entry */
178+
map->inisnull[0]= true;
179+
180+
returnmap;
181+
}
182+
183+
/*
184+
* Set up for tuple conversion, matching input and output columns by name.
185+
* (Dropped columns are ignored in both input and output.) This is intended
186+
* for use when the rowtypes are related by inheritance, so we expect an exact
187+
* match of both type and typmod. The error messages will be a bit unhelpful
188+
* unless both rowtypes are named composite types.
189+
*/
190+
TupleConversionMap*
191+
convert_tuples_by_name(TupleDescindesc,
192+
TupleDescoutdesc,
193+
constchar*msg)
194+
{
195+
TupleConversionMap*map;
196+
AttrNumber*attrMap;
197+
intn;
198+
inti;
199+
boolsame;
200+
201+
/* Verify compatibility and prepare attribute-number map */
202+
n=outdesc->natts;
203+
attrMap= (AttrNumber*)palloc0(n*sizeof(AttrNumber));
204+
for (i=0;i<n;i++)
205+
{
206+
Form_pg_attributeatt=outdesc->attrs[i];
207+
char*attname;
208+
Oidatttypid;
209+
int32atttypmod;
210+
intj;
211+
212+
if (att->attisdropped)
213+
continue;/* attrMap[i] is already 0 */
214+
attname=NameStr(att->attname);
215+
atttypid=att->atttypid;
216+
atttypmod=att->atttypmod;
217+
for (j=0;j<indesc->natts;j++)
218+
{
219+
att=indesc->attrs[j];
220+
if (att->attisdropped)
221+
continue;
222+
if (strcmp(attname,NameStr(att->attname))==0)
223+
{
224+
/* Found it, check type */
225+
if (atttypid!=att->atttypid||atttypmod!=att->atttypmod)
226+
ereport(ERROR,
227+
(errcode(ERRCODE_DATATYPE_MISMATCH),
228+
errmsg_internal("%s",_(msg)),
229+
errdetail("Attribute \"%s\" of type %s does not match corresponding attribute of type %s.",
230+
attname,
231+
format_type_be(outdesc->tdtypeid),
232+
format_type_be(indesc->tdtypeid))));
233+
attrMap[i]= (AttrNumber) (j+1);
234+
break;
235+
}
236+
}
237+
if (attrMap[i]==0)
238+
ereport(ERROR,
239+
(errcode(ERRCODE_DATATYPE_MISMATCH),
240+
errmsg_internal("%s",_(msg)),
241+
errdetail("Attribute \"%s\" of type %s does not exist in type %s.",
242+
attname,
243+
format_type_be(outdesc->tdtypeid),
244+
format_type_be(indesc->tdtypeid))));
245+
}
246+
247+
/*
248+
* Check to see if the map is one-to-one and the tuple types are the
249+
* same. (We check the latter because if they're not, we want to do
250+
* conversion to inject the right OID into the tuple datum.)
251+
*/
252+
if (indesc->natts==outdesc->natts&&
253+
indesc->tdtypeid==outdesc->tdtypeid)
254+
{
255+
same= true;
256+
for (i=0;i<n;i++)
257+
{
258+
if (attrMap[i]!= (i+1))
259+
{
260+
same= false;
261+
break;
262+
}
263+
}
264+
}
265+
else
266+
same= false;
267+
268+
if (same)
269+
{
270+
/* Runtime conversion is not needed */
271+
pfree(attrMap);
272+
returnNULL;
273+
}
274+
275+
/* Prepare the map structure */
276+
map= (TupleConversionMap*)palloc(sizeof(TupleConversionMap));
277+
map->indesc=indesc;
278+
map->outdesc=outdesc;
279+
map->attrMap=attrMap;
280+
/* preallocate workspace for Datum arrays */
281+
map->outvalues= (Datum*)palloc(n*sizeof(Datum));
282+
map->outisnull= (bool*)palloc(n*sizeof(bool));
283+
n=indesc->natts+1;/* +1 for NULL */
284+
map->invalues= (Datum*)palloc(n*sizeof(Datum));
285+
map->inisnull= (bool*)palloc(n*sizeof(bool));
286+
map->invalues[0]= (Datum)0;/* set up the NULL entry */
287+
map->inisnull[0]= true;
288+
289+
returnmap;
290+
}
291+
292+
/*
293+
* Perform conversion of a tuple according to the map.
294+
*/
295+
HeapTuple
296+
do_convert_tuple(HeapTupletuple,TupleConversionMap*map)
297+
{
298+
AttrNumber*attrMap=map->attrMap;
299+
Datum*invalues=map->invalues;
300+
bool*inisnull=map->inisnull;
301+
Datum*outvalues=map->outvalues;
302+
bool*outisnull=map->outisnull;
303+
intoutnatts=map->outdesc->natts;
304+
inti;
305+
306+
/*
307+
* Extract all the values of the old tuple, offsetting the arrays so that
308+
* invalues[0] is left NULL and invalues[1] is the first source attribute;
309+
* this exactly matches the numbering convention in attrMap.
310+
*/
311+
heap_deform_tuple(tuple,map->indesc,invalues+1,inisnull+1);
312+
313+
/*
314+
* Transpose into proper fields of the new tuple.
315+
*/
316+
for (i=0;i<outnatts;i++)
317+
{
318+
intj=attrMap[i];
319+
320+
outvalues[i]=invalues[j];
321+
outisnull[i]=inisnull[j];
322+
}
323+
324+
/*
325+
* Now form the new tuple.
326+
*/
327+
returnheap_form_tuple(map->outdesc,outvalues,outisnull);
328+
}
329+
330+
/*
331+
* Free a TupleConversionMap structure.
332+
*/
333+
void
334+
free_conversion_map(TupleConversionMap*map)
335+
{
336+
/* indesc and outdesc are not ours to free */
337+
pfree(map->attrMap);
338+
pfree(map->invalues);
339+
pfree(map->inisnull);
340+
pfree(map->outvalues);
341+
pfree(map->outisnull);
342+
pfree(map);
343+
}

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