Re: shared memory identification

From: <hailey_kyle_at_my-deja.com>
Date: Mon, 05 Feb 2001 23:28:47 GMT
Message-ID: <95ncv3$pbd$1@nnrp1.deja.com>

Pardon for the last blank messages ( I need a real newsreader!)

On v8

svrmgrl> connect internal
svrmgrl> oradebug setmypid
svrmgrl> oradebug ipc

edit trace file and you will have the shmid's for this db's shared memory

v7
od -X $ORACLE_HOME/dbs/sgadef${ORACLE_SID}.dbf this will give you the shmids of that SID. The first # is the # of shared memory segments. Skip a byte and then you have the addresses of the shared memory segments, continue reading until you hit all bytes of all FFs. When this ends you have the shmids. You can correlate this info using ipcs.

Example structure:
# OFFSET=2
# ---------------------------------------------------------------------
# | start_pos | end_pos | values
# ---------------------|-------------------|---------------------------
# | 1 | 1 | num of shared mem segs
# | OFFSET | OFFSET | ?
# | (OFFSET+1) | (OFFSET)+( SEGS) | (1) address of shared mem
segs
# | (OFFSET+1)+( SEGS)| (OFFSET)+(2*SEGS) | (2) sizes of shared mem
segs
# | (OFFSET+1)+(2*SEGS)| (OFFSET)+(3*SEGS) | (3) id of shared mem segs
# | (OFFSET+1)+(3*SEGS)| end of file | process - semaphore info
# ----------------------------------------------------------------------
#
# if you don't know the SEGS (max shared segs allowed) for the platform
version
# you can generaly tell the number by looking at the sgadef with od -X
# (1) is initialized to FFFFFFFF (value if slot not used)
# (2) is initialized to 00000000 (value if slot not used)
# (3) is initialized to FFFFFFFF (value if slot not used)
# so all the slots that are unused will have either 00000000 or FFFFFFFF
# by counting to the last position for (3) substracting the OFFSET and
# dividing by 3 you have max shared segs allowed - the value of SEG

The sige of SEGS depends on the platform and version. Typical values are 1, 25, 20, 32, 100

For example, Solaris was 20 in 7.3.3 and 100 before that.

Best
Kyle Hailey

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http://www.deja.com/ Received on Mon Feb 05 2001 - 17:28:47 CST