What is Oracle process ID?
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PID is Oracle Process Id(internal to Oracle ) .. found on v$process corresponds to the User Process or Server Process. For each SPID(server level process) there is one PID(oracle process identifier) For this PID there is ADDR value in V$process.
How do I find my Oracle user ID?
Identifying Existing User and Group IDs
- Enter a command similar to the following (in this case, to determine a user ID for the oracle user): Copy # id oracle.
- From the output, identify the user ID ( uid ) for the user and the group identities ( gids ) for the groups to which it belongs.
How do you check if there is a deadlock in Oracle?
ORA-00060: Deadlock detected….In summary, the steps necessary to identify and rectify code causing deadlocks are:
- Locate the error messages in the alert log.
- Locate the relevant trace file(s).
- Identify the SQL statements in both the current session and the waiting session(s).
How can we avoid deadlock in Oracle?
FOR UPDATE or SELECT LOCK IN SHARE MODE ), try using a lower isolation level such as READ COMMITTED . When modifying multiple tables within a transaction, or different sets of rows in the same table, do those operations in a consistent order each time. Then transactions form well-defined queues and do not deadlock.
What is the difference between PID and SID?
In Oracle terms, the SID is roughly equivalent to SPID, as it’s the internal identifier for a session, whereas PID is the actual OS level process ID from Linux/Windows.
What is a process in Oracle?
A process is a mechanism in an operating system that can run a series of steps. The mechanism depends on the operating system. For example, on Linux an Oracle background process is a Linux process. On Windows, an Oracle background process is a thread of execution within a process. Code modules are run by processes.
What is the difference between lock and deadlock in Oracle?
Deadlock occurs when one process is blocked and waiting for a second process to complete its work and release locks, while the second process at the same time is blocked and waiting for the first process to release the lock.
How deadlock is fixed in Oracle?
Resolving Deadlock
- Ask the session getting deadlock error ORA-00060 to issue either COMMIT or ROLLBACK.
- Ask the waiting session to kill the SQL / transaction.
- Look inside alert log / trace file for the sessions involved in deadlock and inform application team to improve the code.
How can we remove deadlock?
Deadlocks can be prevented by preventing at least one of the four required conditions:
- 7.4.1 Mutual Exclusion. Shared resources such as read-only files do not lead to deadlocks.
- 2 Hold and Wait.
- 3 No Preemption.
- 4 Circular Wait.
How can we solve deadlock?
Deadlock frequency can sometimes be reduced by ensuring that all applications access their common data in the same order – meaning, for example, that they access (and therefore lock) rows in Table A, followed by Table B, followed by Table C, and so on.