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This patch for Versions 1 and 2 corrects the following bug:

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In a catalog class that has a "name" type attribute, UPDATEing of an
instance of that class may destroy all of the attributes of that
instance that are stored as or after the "name" attribute.

This is caused by the alignment value of the "name" type being set to
"double" in Class pg_type, but "integer" in Class pg_attribute.
Postgres constructs a tuple using double alignment, but interprets it
using integer alignment.

The fix is to change the alignment to integer in pg_type.

Note that this corrects the problem for new Postgres systems.  Existing
databases already contain the error and it can't easily be repaired because
this very bug prevents updating the class that contains it.

--
Bryan Henderson                                    Phone 408-227-6803
San Jose, California
This commit is contained in:
Marc G. Fournier 1996-08-24 20:56:16 +00:00
parent 208a30f23d
commit 61eaefe9a6
2 changed files with 63 additions and 8 deletions
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24
src/backend/catalog/pg_attribute.h
View File

@ -7,7 +7,7 @@
*
* Copyright (c) 1994, Regents of the University of California
*
* $Id: pg_attribute.h,v 1.2 1996/08/21 04:25:47 scrappy Exp $
* $Id: pg_attribute.h,v 1.3 1996/08/24 20:56:13 scrappy Exp $
*
* NOTES
* the genbki.sh script reads this file and generates .bki
@ -44,13 +44,19 @@ CATALOG(pg_attribute) BOOTSTRAP {
Oid attrelid;
NameData attname;
Oid atttypid;
/* atttypid is the OID of the instance in Catalog Class pg_type that
defines the data type of this attribute (e.g. int4). Information in
that instance is redundant with the attlen, attbyval, and attalign
attributes of this instance, so they had better match or Postgres
will fail.
*/
Oid attdefrel;
int4 attnvals;
Oid atttyparg; /* type arg for arrays/spquel/procs */
int2 attlen;
/* attlen is the number of bytes we use to represent the value
of this attribute, e.g. 4 for an int4. But for a variable length
attribute, attlen is -1.
/* attlen is a copy of the typlen field from pg_type for this
attribute. See atttypid above. See struct TypeTupleFormData for
definition.
*/
int2 attnum;
/* attnum is the "attribute number" for the attribute: A
@ -68,6 +74,10 @@ CATALOG(pg_attribute) BOOTSTRAP {
*/
int2 attbound;
bool attbyval;
/* attbyval is a copy of the typbyval field from pg_type for this
attribute. See atttypid above. See struct TypeTupleFormData for
definition.
*/
bool attcanindex;
Oid attproc; /* spquel? */
int4 attnelems;
@ -80,7 +90,11 @@ CATALOG(pg_attribute) BOOTSTRAP {
walking process.
*/
bool attisset;
char attalign; /* alignment (c=char, s=short, i=int, d=double) */
char attalign;
/* attalign is a copy of the typalign field from pg_type for this
attribute. See atttypid above. See struct TypeTupleFormData for
definition.
*/
} FormData_pg_attribute;
/*

47
src/backend/catalog/pg_type.h
View File

@ -7,7 +7,7 @@
*
* Copyright (c) 1994, Regents of the University of California
*
* $Id: pg_type.h,v 1.3 1996/07/19 05:21:28 scrappy Exp $
* $Id: pg_type.h,v 1.4 1996/08/24 20:56:16 scrappy Exp $
*
* NOTES
* the genbki.sh script reads this file and generates .bki
@ -30,14 +30,34 @@
/* ----------------
* pg_type definition. cpp turns this into
* typedef struct FormData_pg_type
*
* Some of the values in a pg_type instance are copied into
* pg_attribute intances. Some parts of Postgres use the pg_type copy,
* while others use the pg_attribute copy, so they must match.
* See struct FormData_pg_attribute for details.
* ----------------
*/
CATALOG(pg_type) BOOTSTRAP {
NameData typname;
Oid typowner;
int2 typlen;
/* typlen is the number of bytes we use to represent a value of
this type, e.g. 4 for an int4. But for a variable length
attribute, typlen is -1.
*/
int2 typprtlen;
bool typbyval;
/* typbyval determines whether internal Postgres routines pass a value
of this type by value or by reference. Postgres uses a 4 byte
area for passing class data, so if the value is not 1, 2,
or 4 bytes long, Postgres does not have the option of passing by
value and ignores typbyval.
(I don't understand why this attribute exists. The above description
may be an oversimplification. Also, there appear to be bugs in which
Postgres doesn't ignore typbyval when it should, but I'm
afraid to change them until I see proof of damage. -BRYANH 96.08).
*/
char typtype;
bool typisdefined;
char typdelim;
@ -47,7 +67,23 @@ CATALOG(pg_type) BOOTSTRAP {
regproc typoutput;
regproc typreceive;
regproc typsend;
char typalign; /* alignment (c=char, s=short, i=int, d=double) */
char typalign;
/* typalign is the alignment required when storing a value of this
type. It applies to storage on disk as well as most representations
of the value inside Postgres. When multiple values are stored
consecutively, such as in the representation of a complete tuple
on disk, padding is inserted before a datum of this type so that it
begins on the specified boundary. The alignment reference is the
beginning of the first datum in the sequence.
'c' = 1 byte alignment.
's' = 2 byte alignment.
'i' = 4 byte alignment.
'd' = 8 byte alignment.
(This might actually be flexible depending on machine architecture,
but I doubt it - BRYANH 96.08).
*/
text typdefault; /* VARIABLE LENGTH FIELD */
} TypeTupleFormData;
@ -87,6 +123,11 @@ typedef TypeTupleFormData *TypeTupleForm;
/* keep the following ordered by OID so that later changes can be made easier*/
/* Make sure the typlen, typbyval, and typalign values here match the initial
values for attlen, attbyval, and attalign in both places in pg_attribute.h
for every instance.
*/
/* OIDS 1 - 99 */
DATA(insert OID = 16 ( bool PGUID 1 1 t b t \054 0 0 boolin boolout boolin boolout c _null_ ));
@ -95,7 +136,7 @@ DATA(insert OID = 16 ( bool PGUID 1 1 t b t \054 0 0 boolin boolout
DATA(insert OID = 17 ( bytea PGUID -1 -1 f b t \054 0 18 byteain byteaout byteain byteaout i _null_ ));
DATA(insert OID = 18 ( char PGUID 1 1 t b t \054 0 0 charin charout charin charout c _null_ ));
DATA(insert OID = 19 ( name PGUID NAMEDATALEN NAMEDATALEN f b t \054 0 18 namein nameout namein nameout d _null_ ));
DATA(insert OID = 19 ( name PGUID NAMEDATALEN NAMEDATALEN f b t \054 0 18 namein nameout namein nameout i _null_ ));
DATA(insert OID = 20 ( char16 PGUID 16 16 f b t \054 0 18 char16in char16out char16in char16out i _null_ ));
/*DATA(insert OID = 20 ( dt PGUID 4 10 t b t \054 0 0 dtin dtout dtin dtout i _null_ )); */
DATA(insert OID = 21 ( int2 PGUID 2 5 t b t \054 0 0 int2in int2out int2in int2out s _null_ ));