not checking value returned from palloc?
Looking through the postgresql source code, I notice that there are many places
were palloc is used but the return value is not checked to see if it is null.
There are a few places such as:
if (!PointerIsValid(result = palloc(CASH_BUFSZ + 2 - count +
strlen(nsymbol))))
ereport(ERROR,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("out of memory")));
(taken from src/backend/utils/adt/cash.c), but at least within the that same
directory most occurrences of palloc are not checked.
Is this sloppy programming, or is there an automagical thing going on with
#defines that I'm just not seeing?
If it is just sloppy, perhaps we could use a new define in palloc.h, such as:
#define palloc_or_die(ptr,sz) \
do { \
ptr = palloc(sz); \
if (!ptr) \
{ \
ereport(ERROR, \
(errcode(ERRCODE_OUT_OF_MEMORY), \
errmsg("Out of memory"))); \
} \
} while(0);
And then, in all places where the code does not currently check the return value
of palloc, the code could be changed to use palloc_or_die instead. Of course,
I'd be happy if someone has a better name for the macro, perhaps something more
brief?
I can go over the code "with a fine tooth comb" and replace the offending
occurrences. Does the community think this is a good idea?
mark
Mark Dilger wrote:
Looking through the postgresql source code, I notice that there are
many places were palloc is used but the return value is not checked
to see if it is null.
palloc will throw an exception if it cannot fulfill the request. Code
that checks the return value for null is in fact a waste.
--
Peter Eisentraut
http://developer.postgresql.org/~petere/
Mark Dilger <pgsql@markdilger.com> writes:
Looking through the postgresql source code, I notice that there are many places
were palloc is used but the return value is not checked to see if it is null.
Any place that *does* check it is incorrect (in the sense of being
wasted code space, not functionally incorrect). Please read the memmgr
documentation.
regards, tom lane
Peter Eisentraut wrote:
Mark Dilger wrote:
Looking through the postgresql source code, I notice that there are
many places were palloc is used but the return value is not checked
to see if it is null.palloc will throw an exception if it cannot fulfill the request. Code
that checks the return value for null is in fact a waste.
Interesting. So the patch should go the other way, and remove the checks that
are currently in the code?
Mark Dilger wrote:
Peter Eisentraut wrote:
Mark Dilger wrote:
Looking through the postgresql source code, I notice that there are
many places were palloc is used but the return value is not checked
to see if it is null.palloc will throw an exception if it cannot fulfill the request. Code
that checks the return value for null is in fact a waste.Interesting. So the patch should go the other way, and remove the checks
that are currently in the code?
Yes, if you find any such place please submit a patch.
--
Alvaro Herrera http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support
Alvaro Herrera wrote:
Mark Dilger wrote:
Peter Eisentraut wrote:
Mark Dilger wrote:
Looking through the postgresql source code, I notice that there are
many places were palloc is used but the return value is not checked
to see if it is null.palloc will throw an exception if it cannot fulfill the request. Code
that checks the return value for null is in fact a waste.Interesting. So the patch should go the other way, and remove the checks
that are currently in the code?Yes, if you find any such place please submit a patch.
I see one in cash.c that I will remove.
--
Bruce Momjian http://candle.pha.pa.us
SRA OSS, Inc. http://www.sraoss.com
+ If your life is a hard drive, Christ can be your backup. +
