There’s a way to know the REAL memory usage by Oracle Instance, including all connecting processes and using the shell rather than a connection to oracle?<\/p>\n
The short answer is “I think so” \ud83d\ude42<\/p>\n
Summing up RSS column from ps output, is not reliable because Linux uses a copy-on-write on process forks and also doesn’t take into account correctly the shared memory and other shared allocations.<\/p>\n
I’ve come across this post on Pythian’s Blog from Marc Billette<\/a>.<\/p>\n While it seems good I’ve had discording results depending on platform and release.<\/p>\n Instead, I’ve tried to create a shell snippet that always uses pmap but works differently and SEEMS to work correctly on Linux ans Solaris.<\/p>\n Basically, using the pmap script I get a lot of information about the different memory areas allocated to the process:<\/p>\n <\/p>\n Initially I’ve tried to decode correctly the different kinds of memory the same way other scripts I’ve found online do:<\/p>\n but finally the ADDRESS is the same from different processes when the memory area is shared, so my script now just get a unique line for each address and sums up the memory size (not the rss one!):<\/p>\n This should give the total virtual memory allocated by the different Oracle instances.<\/p>\n The results I get are plausible both on Linux and Solaris.<\/p>\n Example:<\/p>\n If you find any error let me know and I’ll fix the script!<\/p>\n —<\/p>\n Ludovico<\/p>\n","protected":false},"excerpt":{"rendered":" There’s a way to know the REAL memory usage by Oracle Instance, including all connecting processes and using the shell rather than a connection to oracle? The short answer is “I think so” \ud83d\ude42 Summing up RSS column from ps … Continue reading 21010: ora_d000_db1p\r\n\r\n0000000000400000 208908K r-x-- \/ccv\/app\/oracle\/product\/11.2.0.3\/bin\/oracle\r\n\r\n000000000D012000 1536K rw--- \/ccv\/app\/oracle\/product\/11.2.0.3\/bin\/oracle\r\n\r\n000000000D192000 1040K rw--- [ heap ]\r\n\r\n0000000060000000 12288K rwxs- [ dism shmid=0x4300000e ]\r\n\r\n0000000080000000 1036288K rwxs- [ dism shmid=0x7600000f ]\r\n\r\n00000000C0000000 12K rwxs- [ dism shmid=0x4f000011 ]\r\n\r\nFFFFFD7FFC7A0000 64K rwx-- [ anon ]\r\n\r\nFFFFFD7FFC7BD000 704K rw--- [ anon ]\r\n\r\nFFFFFD7FFC86E000 200K rw--- [ anon ]\r\n\r\nFFFFFD7FFC8A0000 312K rw--- [ anon ]\r\n\r\nFFFFFD7FFC8EF000 1280K rw--- [ anon ]\r\n\r\nFFFFFD7FFCA30000 64K rwx-- [ anon ]\r\n\r\nFFFFFD7FFCA4F000 256K rw--- [ anon ]\r\n\r\nFFFFFD7FFCA90000 64K rwx-- [ anon ]\r\n\r\nFFFFFD7FFCAB0000 36K r-x-- \/lib\/amd64\/libuutil.so.1\r\n...<\/pre>\n
rwxs- = shared memory\r\n\r\nrw--- = private heap\r\n\r\nrwx-- = private code stack\r\n\r\nr-x-- = shared code stack (?)\r\n\r\netc...<\/pre>\n
username=`whoami`\r\n\r\nsids=`ps -eaf | grep \"^$username\" | grep pmon | grep -v \" grep \" | awk '{print substr($NF,10)}'`\r\n\r\n\r\ntotal=0\r\nfor sid in $sids ; do\r\n pids=`ps -eaf | grep \"^$username\" | grep -- \"$sid\" | grep -v \" grep \" | awk '{print $2}'`\r\n mem=`pmap $pids 2>&1 | grep \"K \" | sort | awk '{print $1 \" \" substr($2,1,length($2)-1)}' | uniq | awk ' BEGIN { sum=0 } { sum+=$2} END {print sum}' `\r\n\r\n echo \"$sid : $mem\"\r\n total=`expr $total + $mem`\r\ndone\r\n\r\necho \"total : $total\"<\/pre>\n$ .\/test_mem.ksh\r\n\r\ndb1p: 3334852\r\n\r\ndb2p: 2052048\r\n\r\ndb3p: 6765280\r\n\r\ndb4p: 2687928\r\n\r\ndb5p: 4385616\r\n\r\ntotal : 19225724<\/pre>\n