Re: [HACKERS] Alpha Size (size_t) != int problem

>
> I've gotten a fairly recent snapshot from FTP and compiled it
> up on Alpha/linux.
>
> On running, the forked process dies with a palloc error....it
> was trying to grab 4 gig worth of memory.
>
> I've tracked this problem down to
> backend/utils/cache/relcache.c
>
> in function init_irels:
> len is defined as Size, which I've checked out and it turns
> out to be size_t...which happens to be 8 byte on an alpha.
> len is uninitialised.
>
> further down in init_irels
> if ((nread = FileRead(fd, (char *) &len, sizeof(int))) != sizeof(int))
>
> which should set len to be the size of the relation read from disk.
> What is happening is that 4 bytes are being read from the file
> and saved in len. Writing 4 into 8 doesn't work too well so a
> complete mess is made.
>
> Initialising len to 0 fixes the problem, but I'm thinking that this
> isn't the best solution. Since len is size_t, I'm figuring that the
> big scheme of things is to allow for larger tables on 64 bit machines.
>
> I'm new to the internals so I don't know if the DB files are architecture
> independant (still wading through documentation)....if it isn't...then I
> guess Size should be replaced with int...and all should be happy.
>
> What is the correct way about fixing this?
>
> My ultimate goal here is to get timestamps working correctly on the alpha.
> You probably already know...but incase you didn't...
>
> create table dat ( d date, t timestamp);
> CREATE
> insert into dat values ('1999-01-22', '1999-01-22 16:00:00');
> INSERT 18602 1
> select * from dat;
> d|t
> ----------+----------------------
> 01-22-1999|2135-02-28 22:28:16+00
> (1 row)
>
> Sometimes...the select the first time returns the correct values...
> but on doing the select again immidately after the first select
> will return 2135 again (probably due to the caching).
>
> Any help on where I should be looking would be greatly received!

I have applied a fix to the tree. The fix is to replace sizeof(int)
with sizeof(len). I checked the rest of the source code, and couldn't
find any other places where this would be a problem.

Patch is attached.

---------------------------------------------------------------------------

Index: relcache.c
===================================================================
RCS file: /usr/local/cvsroot/pgsql/src/backend/utils/cache/relcache.c,v
retrieving revision 1.53
retrieving revision 1.54
diff -c -r1.53 -r1.54
*** relcache.c 1999/01/17 06:18:51 1.53
--- relcache.c 1999/01/22 16:49:25 1.54
***************
*** 7,13 ****
*
*
* IDENTIFICATION
! * $Header: /usr/local/cvsroot/pgsql/src/backend/utils/cache/relcache.c,v 1.53 1999/01/17 06:18:51 momjian Exp $
*
*-------------------------------------------------------------------------
*/
--- 7,13 ----
*
*
* IDENTIFICATION
! * $Header: /usr/local/cvsroot/pgsql/src/backend/utils/cache/relcache.c,v 1.54 1999/01/22 16:49:25 momjian Exp $
*
*-------------------------------------------------------------------------
*/
***************
*** 1876,1882 ****
for (relno = 0; relno < Num_indices_bootstrap; relno++)
{
/* first read the relation descriptor length */
! if ((nread = FileRead(fd, (char *) &len, sizeof(int))) != sizeof(int))
{
write_irels();
return;
--- 1876,1882 ----
for (relno = 0; relno < Num_indices_bootstrap; relno++)
{
/* first read the relation descriptor length */
! if ((nread = FileRead(fd, (char *) &len, sizeof(len))) != sizeof(len))
{
write_irels();
return;
***************
*** 1899,1905 ****
ird->lockInfo = (char *) NULL;

/* next, read the access method tuple form */
! if ((nread = FileRead(fd, (char *) &len, sizeof(int))) != sizeof(int))
{
write_irels();
return;
--- 1899,1905 ----
ird->lockInfo = (char *) NULL;

/* next, read the access method tuple form */
! if ((nread = FileRead(fd, (char *) &len, sizeof(len))) != sizeof(len))
{
write_irels();
return;
***************
*** 1915,1921 ****
ird->rd_am = am;

/* next read the relation tuple form */
! if ((nread = FileRead(fd, (char *) &len, sizeof(int))) != sizeof(int))
{
write_irels();
return;
--- 1915,1921 ----
ird->rd_am = am;

/* next read the relation tuple form */
! if ((nread = FileRead(fd, (char *) &len, sizeof(len))) != sizeof(len))
{
write_irels();
return;
***************
*** 1937,1943 ****
len = ATTRIBUTE_TUPLE_SIZE;
for (i = 0; i < relform->relnatts; i++)
{
! if ((nread = FileRead(fd, (char *) &len, sizeof(int))) != sizeof(int))
{
write_irels();
return;
--- 1937,1943 ----
len = ATTRIBUTE_TUPLE_SIZE;
for (i = 0; i < relform->relnatts; i++)
{
! if ((nread = FileRead(fd, (char *) &len, sizeof(len))) != sizeof(len))
{
write_irels();
return;
***************
*** 1953,1959 ****
}

/* next, read the index strategy map */
! if ((nread = FileRead(fd, (char *) &len, sizeof(int))) != sizeof(int))
{
write_irels();
return;
--- 1953,1959 ----
}

/* next, read the index strategy map */
! if ((nread = FileRead(fd, (char *) &len, sizeof(len))) != sizeof(len))
{
write_irels();
return;
***************
*** 1985,1991 ****
ird->rd_istrat = strat;

/* finally, read the vector of support procedures */
! if ((nread = FileRead(fd, (char *) &len, sizeof(int))) != sizeof(int))
{
write_irels();
return;
--- 1985,1991 ----
ird->rd_istrat = strat;

/* finally, read the vector of support procedures */
! if ((nread = FileRead(fd, (char *) &len, sizeof(len))) != sizeof(len))
{
write_irels();
return;
***************
*** 2082,2089 ****
len = sizeof(RelationData);

/* first, write the relation descriptor length */
! if ((nwritten = FileWrite(fd, (char *) &len, sizeof(int)))
! != sizeof(int))
elog(FATAL, "cannot write init file -- descriptor length");

/* next, write out the Relation structure */
--- 2082,2089 ----
len = sizeof(RelationData);

/* first, write the relation descriptor length */
! if ((nwritten = FileWrite(fd, (char *) &len, sizeof(len)))
! != sizeof(len))
elog(FATAL, "cannot write init file -- descriptor length");

/* next, write out the Relation structure */
***************
*** 2092,2099 ****

/* next, write the access method tuple form */
len = sizeof(FormData_pg_am);
! if ((nwritten = FileWrite(fd, (char *) &len, sizeof(int)))
! != sizeof(int))
elog(FATAL, "cannot write init file -- am tuple form length");

if ((nwritten = FileWrite(fd, (char *) am, len)) != len)
--- 2092,2099 ----

/* next, write the access method tuple form */
len = sizeof(FormData_pg_am);
! if ((nwritten = FileWrite(fd, (char *) &len, sizeof(len)))
! != sizeof(len))
elog(FATAL, "cannot write init file -- am tuple form length");

if ((nwritten = FileWrite(fd, (char *) am, len)) != len)
***************
*** 2101,2108 ****

/* next write the relation tuple form */
len = sizeof(FormData_pg_class);
! if ((nwritten = FileWrite(fd, (char *) &len, sizeof(int)))
! != sizeof(int))
elog(FATAL, "cannot write init file -- relation tuple form length");

if ((nwritten = FileWrite(fd, (char *) relform, len)) != len)
--- 2101,2108 ----

/* next write the relation tuple form */
len = sizeof(FormData_pg_class);
! if ((nwritten = FileWrite(fd, (char *) &len, sizeof(len)))
! != sizeof(len))
elog(FATAL, "cannot write init file -- relation tuple form length");

if ((nwritten = FileWrite(fd, (char *) relform, len)) != len)
***************
*** 2112,2119 ****
len = ATTRIBUTE_TUPLE_SIZE;
for (i = 0; i < relform->relnatts; i++)
{
! if ((nwritten = FileWrite(fd, (char *) &len, sizeof(int)))
! != sizeof(int))
elog(FATAL, "cannot write init file -- length of attdesc %d", i);
if ((nwritten = FileWrite(fd, (char *) ird->rd_att->attrs[i], len))
!= len)
--- 2112,2119 ----
len = ATTRIBUTE_TUPLE_SIZE;
for (i = 0; i < relform->relnatts; i++)
{
! if ((nwritten = FileWrite(fd, (char *) &len, sizeof(len)))
! != sizeof(len))
elog(FATAL, "cannot write init file -- length of attdesc %d", i);
if ((nwritten = FileWrite(fd, (char *) ird->rd_att->attrs[i], len))
!= len)
***************
*** 2123,2130 ****
/* next, write the index strategy map */
len = AttributeNumberGetIndexStrategySize(relform->relnatts,
am->amstrategies);
! if ((nwritten = FileWrite(fd, (char *) &len, sizeof(int)))
! != sizeof(int))
elog(FATAL, "cannot write init file -- strategy map length");

if ((nwritten = FileWrite(fd, (char *) strat, len)) != len)
--- 2123,2130 ----
/* next, write the index strategy map */
len = AttributeNumberGetIndexStrategySize(relform->relnatts,
am->amstrategies);
! if ((nwritten = FileWrite(fd, (char *) &len, sizeof(len)))
! != sizeof(len))
elog(FATAL, "cannot write init file -- strategy map length");

if ((nwritten = FileWrite(fd, (char *) strat, len)) != len)
***************
*** 2132,2139 ****

/* finally, write the vector of support procedures */
len = relform->relnatts * (am->amsupport * sizeof(RegProcedure));
! if ((nwritten = FileWrite(fd, (char *) &len, sizeof(int)))
! != sizeof(int))
elog(FATAL, "cannot write init file -- support vector length");

if ((nwritten = FileWrite(fd, (char *) support, len)) != len)
--- 2132,2139 ----

/* finally, write the vector of support procedures */
len = relform->relnatts * (am->amsupport * sizeof(RegProcedure));
! if ((nwritten = FileWrite(fd, (char *) &len, sizeof(len)))
! != sizeof(len))
elog(FATAL, "cannot write init file -- support vector length");

if ((nwritten = FileWrite(fd, (char *) support, len)) != len)

--
Bruce Momjian | http://www.op.net/~candle
maillist(at)candle(dot)pha(dot)pa(dot)us | (610) 853-3000
+ If your life is a hard drive, | 830 Blythe Avenue
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