pg core dump

pg_core_dump_ubuntu_example

# i modified https://github.com/postgres/postgres/blob/7c44c46deb495a2f3861f402d7f2109263e3d50a/src/backend/access/common/heaptuple.c#L94
to 
if (att->atthasmissing)  -> if (! att->atthasmissing)

# https://www.highgo.ca/2019/10/03/trace-query-processing-internals-with-debugger/
recompiled and make install
 ./configure --prefix /home/postgres/example/pgsql --enable-debug 2>&1 >/dev/null
 make install
 
then ran the test to reproduce
# https://github.com/postgres/postgres/blob/7c44c46deb495a2f3861f402d7f2109263e3d50a/src/test/regress/expected/fast_default.out


postgres@db:~/example$ ulimit -c
unlimited
postgres@db:~/example$ export PATH=/home/postgres/.pyenv/shims:/home/postgres/.pyenv/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/home/postgres/example/pgsql/bin
postgres@db:~/example$ pg_ctl -D example -l logfile stop                                                                                waiting for server to shut down.... done
server stopped
postgres@db:~/example$ pg_ctl -D example -l logfile start
waiting for server to start.... done
server started
postgres@db:~/example$ psql
psql (13.3)
Type "help" for help.

postgres=# drop table t1;
DROP TABLE
postgres=# CREATE TABLE t1 AS
SELECT 1::int AS a , 2::int AS b
FROM generate_series(1,20) q;
SELECT 20
postgres=# ALTER TABLE t1 ADD COLUMN c text;
ALTER TABLE
postgres=# SELECT a,
       stddev(cast((SELECT sum(1) FROM generate_series(1,20) x) AS float4))
          OVER (PARTITION BY a,b,c ORDER BY b)
       AS z
FROM t1;
server closed the connection unexpectedly
        This probably means the server terminated abnormally
        before or while processing the request.
The connection to the server was lost. Attempting reset: Succeeded.
postgres=# \q
postgres@db:~/example$ ls -lrt
total 175612
drwx------ 19 postgres postgres      4096 Jun 30 14:20 example
-rw-------  1 postgres postgres 151969792 Jun 30 14:20 core.1000.postgres.23620


postgres@db:~/example$ chmod a+rwx core.1000.postgres.23620
postgres@db:~/example$ sudo  gdb /home/postgres/example/pgsql/bin/postgres /home/postgres/example/core.1000.postgres.23620
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Reading symbols from /home/postgres/example/pgsql/bin/postgres...
[New LWP 23620]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
Core was generated by `postgres: postgres postgres [local] SELECT          '.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  0x000055b0342c3771 in getmissingattr ()  -- right at the place where i made that change
(gdb) bt
#0  0x000055b0342c3771 in getmissingattr ()
#1  0x000055b0346c0f4f in comparetup_heap ()
#2  0x000055b0346bddad in qsort_tuple ()
#3  0x000055b0346c3768 in tuplesort_performsort ()
#4  0x000055b034464038 in ExecSort ()
#5  0x000055b034467ff0 in begin_partition ()
#6  0x000055b03446b3b5 in ExecWindowAgg ()
#7  0x000055b0344389a3 in standard_ExecutorRun ()
#8  0x000055b03458f4bc in PortalRunSelect ()
#9  0x000055b0345906be in PortalRun ()
#10 0x000055b03458c42c in exec_simple_query ()
#11 0x000055b03458e012 in PostgresMain ()
#12 0x000055b034519fcf in ServerLoop ()
#13 0x000055b03451af2b in PostmasterMain ()
#14 0x000055b0342bacf2 in main ()
(gdb) quit