fix another cs_hash_dup_count

[amutu]

imcs_dup_hash_initialize should be fixed also as last commit

[amutu]

thanks for your fix of the imcs_dup_hash_count,but when I try a larger data set,eg more than 5 million rows,the segment fault happens again.After debug,I find this time,the semgment fault happened at the the imcs_dup_hash_initialize,similar with the last.So I fixed it and pull the commit.

this is gdb info:

0x00007f4472db49bd in imcs_dup_hash_initialize (iterator=0x7f282c0008f0) at func.c:5833
5833 elem->count += 1;
(gdb) bt
#0 0x00007f4472db49bd in imcs_dup_hash_initialize (iterator=0x7f282c0008f0) at func.c:5833
#1 0x00007f4472cda11e in imcs_parallel_job (worker_id=16, n_workers=24, arg=0x228fc58) at imcs.c:1725
#2 0x00007f4472dc45ca in imcs_thread_pool_worker (pool=0x224c650) at threadpool.c:33
#3 0x00007f4472aa87f1 in start_thread () from /lib64/libpthread.so.0
#4 0x00007f4478f62ccd in clone () from /lib64/libc.so.6
(gdb) print elem
$1 = (imcs_hash_elem_t *) 0x0
(gdb) l
5828 agg_elem->count = 0;
5829 agg_elem->collision = agg_hash->table[agg_index];
5830 agg_hash->table[agg_index] = agg_elem;
5831 }
5832 if (++agg_elem->count == ctx->min_occurrences) {
5833 elem->count += 1;
5834 }
5835 }
5836 }
5837 agg_hash->table_used = agg_distinct_count;
(gdb) quit
A debugging session is active.

[knizhnik]

Thank you very much for pointing this issues.
Shame on me: I really do not not notice the same problem in mco_seq_dup_hash_initialize.
I also merge most of your other fixes.
But I do not think that it is good idea to implicitly replace min_occ <= 0 with 1. I prefer to report error in this case.

[amutu]

thanks,I think min_occ <= 0 report error is OK. I indeed implement the error at first,but after I test the behaviour of substring(s string,start int) function of the PostgreSQL,I find substring do not report error and just set start to 1 when start <= 0:
postgres=# select substring('abcdef',1);

substring

abcdef
(1 row)

postgres=# select substring('abcdef',2);

substring

bcdef
(1 row)

postgres=# select substring('abcdef',3);

substring

cdef
(1 row)

postgres=# select substring('abcdef',7);

substring

(1 row)

postgres=# select substring('abcdef',0);

substring

abcdef
(1 row)

postgres=# select substring('abcdef',-1);

substring

abcdef
(1 row)