RAC GES Processes

In RAC environments, GES process structures are used to record details about local and remote processes with an interest in global locks.

There must be one GES process for each process in each instance in the cluster. Therefore there will be more GES process structures in each instance than KSUPR (process) structures.

I think that the abbreviation for GES processes is kjp

In the SGA there are two main GES process structures:

• ges process array
• ges process hash table

In Oracle 10.2.0.1 (32-bit Linux) the ges process array occupies 256000 bytes

• Each element is 800 bytes in length.
• The number of elements is defined by the _LM_PROCS initialization parameter
• The default value for _LM_PROCS is 320 (where PROCESSES = 150)

In Oracle 10.2.01 (32-bit Linux) the ges process hash table occupies 8640 bytes

GES process structures are covered by three latches:

Latch Name	Variable Name
ges process parent latch	kjptfl_
ges process hash list	kjplat_
ges process table freelist	kjphsh_

In Oracle 10.2.0.1 (32-bit Linux) :

• The ges process table freelist does not have any children
• The ges process parent latch has one child for each GES process
• The ges process hash list does not have any children

Static kjp structures are also allocated for

• kjplmon_
• kjppmon_

A list of addresses of kjp structures can be obtained using

SQL> ORADEBUG LKDEBUG -a proc

For example

nproc = 30 proc 0 0x2f43a730 proc 1 0x2f435f50 proc 2 0x2f43a410 proc 3 0x2f4381b0 proc 4 0x2f43ad70 proc 5 0x2f436270 etc...

You can dump detailed information for each GES process using

SQL> ORADEBUG LKDEBUG -A proc

This command produces output in the following format for each GES process.

--------procp 0x2f43a730----------------- proc version : 0 Local node : 0 pid : 6480 lkp_node : 0 svr_mode : 0 proc state : KJP_NORMAL Last drm hb acked : 0 Total accesses : 69131 Imm. accesses : 69130 Locks on ASTQ : 0 Locks Pending AST : 0 Granted locks : 0

Possible values for the process state are probably KJP_NORMAL, KJP_FREEZE and KJP_UNFREEZE

The GES process structures also appear in the SYSTEMSTATE (level 10) dump:

SQL> ALTER SESSION SET EVENTS 'IMMEDIATE TRACE NAME SYSTEMSTATE LEVEL 10';

SO: 0x2f43a730, type: 19, owner: 0x30222a18, flag: INIT/-/-/0x00 GES MSG BUFFERS: st=emp chunk=0x(nil) hdr=0x(nil) lnk=0x(nil) flags=0x0 inc=4 outq=0 sndq=0 opid=36 prmb=0x0 mbg[i]=(1 6) mbg[b]=(0 0) mbg[r]=(0 0) fmq[i]=(4 1) fmq[b]=(0 0) fmq[r]=(0 0) mop[s]=7 mop[q]=0 pendq=0 zmbq=0 ------------process 0x0x2f43a730-------------------- proc version : 0 Local node : 0 pid : 6480 lkp_node : 0 svr_mode : 0 proc state : KJP_NORMAL Last drm hb acked : 0 Total accesses : 76137 Imm. accesses : 76135 Locks on ASTQ : 0 Locks Pending AST : 0 Granted locks : 0 AST_Q: PENDING_Q: GRANTED_Q:

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