cs_hash_dup_count crash backend

[amutu]

select agg_val,group_by from crashlog_get('{604176597}'::int[]),cs_project_agg(cs_hash_dup_count(uin,cs_filter(class1=cs_const('737a7612853859405ba846b99f35f4c3'),class2))) order by 1 desc limit 5;

glibc-2.12-1.49.tl1.x86_64
(gdb) c
Continuing.
[New Thread 0x7f7217ef8700 (LWP 18782)]
[New Thread 0x7f72176f7700 (LWP 18783)]
[New Thread 0x7f7216ef6700 (LWP 18784)]
[New Thread 0x7f72166f5700 (LWP 18785)]
[New Thread 0x7f7215ef4700 (LWP 18786)]
[New Thread 0x7f72156f3700 (LWP 18787)]
[New Thread 0x7f7214ef2700 (LWP 18788)]
[New Thread 0x7f72146f1700 (LWP 18789)]
[New Thread 0x7f7213ef0700 (LWP 18790)]
[New Thread 0x7f72136ef700 (LWP 18791)]
[New Thread 0x7f7212eee700 (LWP 18792)]
[New Thread 0x7f72126ed700 (LWP 18793)]
[New Thread 0x7f7211eec700 (LWP 18794)]
[New Thread 0x7f72116eb700 (LWP 18795)]
[New Thread 0x7f7210eea700 (LWP 18796)]
[New Thread 0x7f72106e9700 (LWP 18797)]

Program received signal SIGSEGV, Segmentation fault.
0x00007f7e25c9b28b in imcs_thread_pool_wait (pool=0xb61940) at threadpool.c:45
45 pool->sync->unlock(pool->sync);
(gdb) print pool->sync
$1 = (imcs_mutex_t *) 0x0
(gdb) bt
#0 0x00007f7e25c9b28b in imcs_thread_pool_wait (pool=0xb61940) at threadpool.c:45
#1 0x0000000700004201 in ?? ()
#2 0x0000000000000000 in ?? ()

(gdb) \l
Undefined command: "". Try "help".
(gdb) l
40 {
41 pool->sync->lock(pool->sync);
42 pool->work_id = 0;
43 pool->start->signal(pool->start, pool->n_workers);
44 pool->finish->wait(pool->finish, pool->sync, pool->n_workers, IMCS_TM_INFINITE);
45 pool->sync->unlock(pool->sync);
46
47 }
48 int counters[4] = {0,0,0,0};
49 static void imcs_thread_pool_execute(struct imcs_thread_pool_t* self, imcs_job_t job, void* arg)
(gdb)

if use cs_hash_count,the sql will run ok

[amutu]

some more info

for un init cs,the sql emmit other error:
crash=> select agg_val,group_by from crashlog_get('{604176597}'::int[]),cs_project_agg(cs_hash_dup_count(uin,cs_filter(class1=cs_const('737a7612853859405ba846b99f35f4c3'),class2))) order by 1 desc limit 5;
NOTICE: IMCS command: const
CONTEXT: PL/pgSQL function cs_const(text) line 1 at RETURN
ERROR: function returning set of rows cannot return null value

for loaded small data, the sql run OK:
crash=> select agg_val,group_by from crashlog_get('{604176597}'::int[]),cs_project_agg(cs_hash_dup_count(uin,cs_filter(class1=cs_const('737a7612853859405ba846b99f35f4c3'),class2))) order by 1 desc limit 5;
NOTICE: IMCS command: const
CONTEXT: PL/pgSQL function cs_const(text) line 1 at RETURN
NOTICE: IMCS command: eq
NOTICE: IMCS command: filter
NOTICE: IMCS command: hash_dup_count
NOTICE: IMCS command: project_agg
agg_val | group_by
---------+----------
(0 rows)

for bigger data,it emmit different error message and also crash the backend:
crash=> select agg_val,group_by from crashlog_get('{604176597}'::int[]),cs_project_agg(cs_hash_dup_count(uin,cs_filter(class1=cs_const('737a7612853859405ba846b99f35f4c3'),class2))) order by 1 desc limit 5;
NOTICE: IMCS command: const
CONTEXT: PL/pgSQL function cs_const(text) line 1 at RETURN
NOTICE: IMCS command: eq
NOTICE: IMCS command: filter
NOTICE: IMCS command: hash_dup_count
NOTICE: IMCS command: project_agg
ERROR: group by sequence doesn't match values sequence
crash=> select agg_val,group_by from crashlog_get('{604176597}'::int[]),cs_project_agg(cs_hash_dup_count(uin,cs_filter(class1=cs_const('737a7612853859405ba846b99f35f4c3'),class2))) order by 1 desc limit 5;
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.

[knizhnik]

Looks like in both cases memory corruption takes place.
Can you provide me with full data needed to reproduce the problem?

[amutu]

some more case:
crash=> select agg_val,group_by from crashlog_get('{604176597}'::int[]),cs_project_agg(cs_hash_dup_count(uin,class2)) order by 1 desc limit 5;
NOTICE: IMCS command: hash_dup_count
NOTICE: IMCS command: project_agg
agg_val | group_by
---------+--------------------------------------------------------------------
37 | \x6439613632326233396138316163373737316238343338373634333131353961
32 | \x6536623933633334343963373530663538383335663133616663643865316530
22 | \x3732646365313766623262646530373266303465383763343962313537313665
18 | \x3130376131386265353733316331613163306338353533616466666564636462
10 | \x6530623266613538386134343637353563666466316535303163656631306532
(5 rows)
crash=> select agg_val,group_by from crashlog_get('{604176597}'::int[]),cs_project_agg(cs_hash_dup_count(uin,cs_filter(cs_const(1)=cs_const(1),class2))) order by 1 desc limit 5;
NOTICE: IMCS command: const
CONTEXT: PL/pgSQL function cs_const(double precision,cs_elem_type) line 1 at RETURN
NOTICE: IMCS command: const
CONTEXT: PL/pgSQL function cs_const(double precision,cs_elem_type) line 1 at RETURN
NOTICE: IMCS command: eq
NOTICE: IMCS command: filter
NOTICE: IMCS command: hash_dup_count
NOTICE: IMCS command: project_agg
agg_val | group_by
---------+--------------------------------------------------------------------
37 | \x6439613632326233396138316163373737316238343338373634333131353961
32 | \x6536623933633334343963373530663538383335663133616663643865316530
22 | \x3732646365313766623262646530373266303465383763343962313537313665
18 | \x3130376131386265353733316331613163306338353533616466666564636462
10 | \x6530623266613538386134343637353563666466316535303163656631306532
(5 rows)

crash=> select agg_val,group_by from crashlog_get('{604176597}'::int[]),cs_project_agg(cs_hash_dup_count(uin,cs_filter(class1=cs_const('737a7612853859405ba846b99f35f4c3'),class2))) order by 1 desc limit 5;
NOTICE: IMCS command: const
CONTEXT: PL/pgSQL function cs_const(text) line 1 at RETURN
NOTICE: IMCS command: eq
NOTICE: IMCS command: filter
NOTICE: IMCS command: hash_dup_count
NOTICE: IMCS command: project_agg
ERROR: group by sequence doesn't match values sequence
crash=> select agg_val,group_by from crashlog_get('{604176597}'::int[]),cs_project_agg(cs_hash_dup_count(uin,cs_filter(cs_const(1)=cs_const(1),class2))) order by 1 desc limit 5;
ERROR: group by sequence doesn't match values sequence
crash=> select agg_val,group_by from crashlog_get('{604176597}'::int[]),cs_project_agg(cs_hash_dup_count(uin,class2)) order by 1 desc limit 5;
NOTICE: IMCS command: const
CONTEXT: PL/pgSQL function cs_const(double precision,cs_elem_type) line 1 at RETURN
NOTICE: IMCS command: const
CONTEXT: PL/pgSQL function cs_const(double precision,cs_elem_type) line 1 at RETURN
NOTICE: IMCS command: eq
NOTICE: IMCS command: filter
NOTICE: IMCS command: hash_dup_count
NOTICE: IMCS command: project_agg
The connection to the server was lost. Attempting reset: Failed.
!>

I will dump the data to you.

[knizhnik]

Actually the query you are using is not correct: there is inconsistency between "values" and "group-by" sequences in hash_agg operator. You should duplicate filter condition:
cs_hash_dup_count(cs_filter(class1=cs_const('737a7612853859405ba846b99f35f4c3'),uin),
cs_filter(class1=cs_const('737a7612853859405ba846b99f35f4c3'),class2))

[amutu]

Oh,I get it.Thank you for your explaination.
So the followed crash caused by this error? do I need provide the data?

[knizhnik]

Not sure if crash really caused by this error.
But in any case such error should cause crash.
So I will be pleased if you can help me to reproduce the problem.

[amutu]

I have send the data to you by email.

[knizhnik]

The problem was caused by non-reentrant (thread-unsafe) errro reporting in PostgreSQL (because PostgreSQL itself is not using threads).
I implemented thread-safe error reporting in IMCS (revision 57).
Now this query correctly returns error without memory corruption.