Hi to all;
1.Can semaphore allow two different process at a time?
2. Is there any Max limiy ?
I am trying to find how semaphores prevents two different processes at a time as well as checked semaphore array no's.
I updated two tables sententiously. Here , semaphores allowed two process updating table con currently.
1. Can anyone clear my confusion ?
Semephore allocated same arrays for two different processes but linux says semaphore allocates different arrays for each process. but in ouput not found different arrays.
PHP Code:
SQL> show user;
USER is "SONY"
SQL> update tab3 set name='SONY';
200000 rows updated.
PHP Code:
SQL> show user;
USER is "SONA"
SQL> update tab4 set name='SONA';
200000 rows updated.
>> Before UPDATE THE TABLE >>
PHP Code:
[oracle@localhost ~]$ ipcs
------ Shared Memory Segments --------
key shmid owner perms bytes nattch status
0xc2da0d04 458763 oracle 640 287309824 19
------ Semaphore Arrays --------
key semid owner perms nsems
0xd5f61564 229376 oracle 640 154
------ Message Queues --------
key msqid owner perms used-bytes messages
>> When updating tables >>
PHP Code:
[oracle@localhost ~]$ ipcs
------ Shared Memory Segments --------
key shmid owner perms bytes nattch status
0xc2da0d04 458763 oracle 640 287309824 19
------ Semaphore Arrays --------
key semid owner perms nsems
0xd5f61564 229376 oracle 640 154
------ Message Queues --------
key msqid owner perms used-bytes messages
>> After Updated the tables>>
PHP Code:
[oracle@localhost ~]$ ipcs
------ Shared Memory Segments --------
key shmid owner perms bytes nattch status
0xc2da0d04 458763 oracle 640 287309824 19
------ Semaphore Arrays --------
key semid owner perms nsems
0xd5f61564 229376 oracle 640 154
------ Message Queues --------
key msqid owner perms used-bytes messages
BEFORE , CURRENT , After ( table updation) why ipcs showing same
address here ?
Regards
Thiyagusham .G