V$SESSION

Kill and Disconnect Oracle Sessions with ALTER SYSTEM Purpose V$SESSION exposes the SID and SERIAL# pair that both ALTER SYSTEM KILL SESSION and ALTER SYSTEM DISCONNECT SESSION require as their targeting key — a DBA cannot terminate a stuck session without pulling that pair first, and getting it wrong means terminating …

Enable a 10046 Trace for an Oracle Session Purpose A 10046 trace returns wait events only if the level includes them. Enabling the trace at level 1 and then wondering why the file shows no waits is the most common 10046 mistake in production diagnosis — the output has elapsed times and call counts, but none of the db …

Monitor Data Pump Progress with V$SESSION_LONGOPS Purpose Where the expdp and impdp log files record a status line per completed object — writing output at each table boundary, not while a large table is mid-transfer — V$SESSION_LONGOPS records progress while the operation is still running. That gap matters on a …

Check RESUMABLE_TIMEOUT and RESUMABLE Status in V$SESSION Purpose V$SESSION carries two columns that tell you whether a session can survive running out of space: RESUMABLE and the resumable timeout that governs it. When resumable space allocation is enabled, a statement that hits a space error — a full tablespace, a …

Query Wait Events by Session with Oracle V$SESSION_WAIT Purpose V$SESSION_WAIT is the real-time view that shows what each Oracle session is waiting on this very second. For every session it exposes the wait event name, how long the session has been in that wait, and three event-specific parameters (P1, P2, P3) that …

Oracle Time Model Queries: System and Session Performance Monitoring Purpose Oracle time model queries provide database administrators with powerful tools to measure and analyze where time is spent within the database system. These queries use two essential dynamic performance views that track accumulated time for …

Monitoring PGA Usage by Username in Oracle Database Effective memory management is critical for Oracle Database administrators (DBAs) when diagnosing performance issues. Oracle uses the Program Global Area (PGA) for managing session memory, including operations like sorting, hashing, and storing session context. …

Oracle "Data Block" Waits using Oracle table v$waitstat to identify disk Contention Purpose In Oracle databases, waiting for "data blocks" signifies contention for specific data blocks in memory. This contention can lead to performance bottlenecks and slowdowns. Understanding the root cause of these waits is crucial to …

Unmasking Buffer Busy Waits in Oracle: A Deep Dive with v$session_wait Purpose "Buffer busy waits" are a common performance bottleneck in Oracle databases, occurring when multiple sessions try to access the same data block concurrently. Identifying the specific blocks and understanding the reasons behind these waits is …

Identifying Locked Rows in Oracle Database using tables v$session and dba_objects Purpose This Oracle query pinpoints the exact row a specific session is waiting on due to a lock. It first finds the locked object and row location, then constructs a ROWID to fetch and display the entire locked row from the table. Sample …