gistfile1.txt

 ./configure --prefix /opt/17/usr/local --enable-tap-tests --with-perl --with-python --with-openssl --enable-dtrace --enable-debug --enable-cassert CFLAGS="-ggdb -Og -g3 -fno-omit-frame-pointer -DLOCK_DEBUG -DBTREE_BUILD_STATS -DWAL_DEBUG"
 make 
 make install
 
 export PATH=/opt/17/usr/local/bin:$PATH
 
 select name,setting from pg_settings where name ~ 'trace.*locks';
      name       | setting
-----------------+---------
 trace_locks     | on
 trace_lwlocks   | on
 trace_userlocks | on
(3 rows)



postgres=# show trace_lock_table;
 trace_lock_table
------------------
 0
(1 row)

postgres=# create table t(col1 int primary key);
CREATE TABLE
postgres=# select 't'::regclass::oid;
  oid
-------
 16398
(1 row)

postgres=# set trace_lock_table = 16398;
SET

postgres=# alter table t add column col4 bigint;
ALTER TABLE


---then in logs 

2024-04-29 16:25:33.608 IST [11801] LOG:  LockAcquire: new: lock(0x7f3d498989d0) id(5,16419,0,0,0,1) grantMask(0) req(0,0,0,
0,0,0,0)=0 grant(0,0,0,0,0,0,0)=0 wait(0) type(AccessExclusiveLock)
2024-04-29 16:25:33.608 IST [11801] STATEMENT:  alter table t add column col4 bigint;
2024-04-29 16:25:33.608 IST [11801] LOG:  LockAcquire: new: proclock(0x7f3d49949e30) lock(0x7f3d498989d0) method(1) proc(0x7f3d49c49590) hold(0)
2024-04-29 16:25:33.608 IST [11801] STATEMENT:  alter table t add column col4 bigint;
2024-04-29 16:25:33.608 IST [11801] LOG:  LockCheckConflicts: no conflict: proclock(0x7f3d49949e30) lock(0x7f3d498989d0) method(1) proc(0x7f3d49c49590) hold(0)
2024-04-29 16:25:33.608 IST [11801] STATEMENT:  alter table t add column col4 bigint;
2024-04-29 16:25:33.608 IST [11801] LOG:  GrantLock: lock(0x7f3d498989d0) id(5,16419,0,0,0,1) grantMask(100) req(0,0,0,0,0,0,0)=1 grant(0,0,0,0,0,0,0)=1 wait(0) type(AccessExclusiveLock)
2024-04-29 16:25:33.608 IST [11801] STATEMENT:  alter table t add column col4 bigint;
2024-04-29 16:25:33.608 IST [11801] LOG:  11801: LWLockRelease(LockManager 0x7f3d41084c00): excl 1 shared 0 haswaiters 0 waiters 0 rOK 1