From:Steve Adams
Date:18-Dec-2000 12:18
Subject:   PMON unable to acquire latch

The trace file shows that PMON has twice given up on an attempt to acquire the modify parameter values latch. It was being held firstly by process 111 and later by process 19. User processes need this latch to read the parameter values in the SGA on process startup. The fact that it being held for a long time suggests that you have a performance problem that is causing process startup to take a long time. The problem could be an Oracle issue such as library cache latch contention, or a Solaris issue such as virtual memory thrashing, or it could just be that there were too many simultaneous connection attempts.

Can you tell me what this message means? 
Dump file /oracle/app/oracle/admin/WEB01/bdump/web01_pmon_16405.trc
Oracle8 Enterprise Edition Release 8.0.6.1.0 - Production
With the Partitioning, Objects and Parallel Server options
PL/SQL Release 8.0.6.1.0 - Production
ORACLE_HOME = /oracle/app/oracle/product/806
System name:    SunOS
Node name:      db1
Release:        5.6
Version:        Generic_105181-23
Machine:        sun4u
Instance name: WEB01
Redo thread mounted by this instance: 1
Oracle process number: 2
Unix process pid: 16405, image: ora_pmon_WEB01

*** 2000-12-17 05:34:52.109
*** SESSION ID:(1.1) 2000-12-17 05:34:52.090
PMON unable to acquire latch 80002c4c modify parameter values
  possible holder pid = 111 ospid=15220
*** 2000-12-17 05:34:52.109
*** 2000-12-17 05:55:19.770
PMON unable to acquire latch 80002c4c modify parameter values
  possible holder pid = 19 ospid=15915
*** 2000-12-17 05:55:19.770
*** 2000-12-17 06:22:16.374