Valgrind mem-check for postgres extension

Natarajan R <nataraj3098@gmail.com> writes:

I have few doubts in here,

1. When I run with *--leak-check=full*, I get memory leaks for postgres
functions under possibly or definitely lost categories.. Is this expected?

Maybe ... you did not show your test case, so it's hard to say. But it
could well be that this is an artifact of failing to define USE_VALGRIND.

2. Is there any other way to test my extension memory leaks alone, because
combining with postgres leaks is making instrumentation complex?..

No, not really.

3. I have seen some macros for valgrind support within postgres source code
under utils/memdebug.h, but couldn't get complete idea of using it from the
comments in pg_config_manual.h under *USE_VALGRIND *macro, pls provide some
guidance here..

If you didn't build the core code with USE_VALGRIND defined, then none of
this stuff is going to work ideally.

The way I like to do it is to run configure, and then manually add
"#define USE_VALGRIND" to the generated src/include/pg_config.h
file before invoking "make". Probably other people have different
habits.

regards, tom lane

On 2022-05-18 We 01:12, Tom Lane wrote:

Natarajan R <nataraj3098@gmail.com> writes:

I have few doubts in here,
1. When I run with *--leak-check=full*, I get memory leaks for postgres
functions under possibly or definitely lost categories.. Is this expected?

Maybe ... you did not show your test case, so it's hard to say. But it
could well be that this is an artifact of failing to define USE_VALGRIND.

2. Is there any other way to test my extension memory leaks alone, because
combining with postgres leaks is making instrumentation complex?..

No, not really.

3. I have seen some macros for valgrind support within postgres source code
under utils/memdebug.h, but couldn't get complete idea of using it from the
comments in pg_config_manual.h under *USE_VALGRIND *macro, pls provide some
guidance here..

If you didn't build the core code with USE_VALGRIND defined, then none of
this stuff is going to work ideally.

The way I like to do it is to run configure, and then manually add
"#define USE_VALGRIND" to the generated src/include/pg_config.h
file before invoking "make". Probably other people have different
habits.

The standard buildfarm config uses these for valgrind builds:

        CFLAGS   => "-fno-omit-frame-pointer -O0 -fPIC",
        CPPFLAGS => "-DUSE_VALGRIND  -DRELCACHE_FORCE_RELEASE",

cheers

andrew

--
Andrew Dunstan
EDB: https://www.enterprisedb.com

I have few doubts in here,
1. When I run with *--leak-check=full*, I get memory leaks for postgres
functions under possibly or definitely lost categories.. Is this

expected?

Maybe ... you did not show your test case, so it's hard to say. But it
could well be that this is an artifact of failing to define USE_VALGRIND

I did not run any test, just simply started the plain postgres(my extension
not installed) with valgrind(command given below)..

*valgrind --leak-check=full --suppressions=src/tools/valgrind.supp
--time-stamp=yes --error-markers=VALGRINDERROR-BEGIN,VALGRINDERROR-END
--trace-children=yes --log-file=pg_valgrind/pg-valgrind_%p.log postgres -D
data*

3. I have seen some macros for valgrind support within postgres source

code

under utils/memdebug.h, but couldn't get complete idea of using it from

the

comments in pg_config_manual.h under *USE_VALGRIND *macro, pls provide

some

guidance here..

If you didn't build the core code with USE_VALGRIND defined, then none of
this stuff is going to work ideally.

The way I like to do it is to run configure, and then manually add
"#define USE_VALGRIND" to the generated src/include/pg_config.h
file before invoking "make". Probably other people have different
habits.

I tried the things like you said
1. Pg configured already, so #define USE_VALGRIND in src/include/pg_config.h
2. make, make install
3. started pg with valgrind(same command mentioned above)..
Now, memory leaks are being reported for palloc, malloc, MemoryContextAlloc
functions..(sample image from a valgrind report for a process attached).
I couldn't specify from which process, this was generated.. as the valgrind
provide pid alone..

[image: image.png]

In an overview, I am trying to test a memory leak for my extension, correct
me if i am doing it the wrong way..

Regards,
Natarajan R

On Wed, 18 May 2022 at 21:38, Andrew Dunstan <andrew@dunslane.net> wrote: