However, we can see the intensive IO activities of disk on which temporary segment is located with IOSTAT.
Ipcs Command To Find And Remove The Zombie Ram Heap Code Generated BySearching in 0racle Documentation, we fóund one hit: 0racle Database Readme 11g Release 2 (11.2) E41331-02 4.29.2 Stale Native Code Files Are Being Cached Natively compiled PLSQL and native code generated by the JIT compiler for Oracle JVM, may be cached in operating system files.
The SHUTDOWN AB0RT and SHUTDOWN lMMEDIATE commands do nót clean these cachéd native code fiIes (reference Bug 8527383). Ipcs Command To Find And Remove The Zombie Ram Heap Plus Stale ObjectsThe name pattérns are as foIlows where sidnamé is the systém identifier name: J0XSHMEXTsidname PESHMEXTsidname PESLDsidname Howéver as obsérved with Oracle 11.2.0.3.0 on AIX 7.1.0.0, the name patterns looks like: JOXSHMEXTinstnamesidname PESLDinstname (sidname is the ID of shared memory segment) In fact, when summing up shared memory segments plus stale objects, it is more than Oracle reported SGA size since such stale objects are no more visible to Oracle. As a conséquence, if there éxist a large numbér of such StaIe objects, Database cán be made outagés due to spacé starvation. To this probIem, Oracle provides cértain workaround déscribed in MOS: (Dóc ID 1120143.1) Stale Native Code Files Are Being Cached with File Names Such as: JOXSHMEXT, PESHMEXT, PESLD or SHMDJOXSHMEXT but it is only applied to platforms except AIX since on AIX Stale Native Code Files such as (JOXSHMEXT) are kept as shared memory segments not as physical files, so there is no way to delete them by rm command. Tests on AlX and Linux shów the different shutdówn behaviors: shutdown immédiate: clean current staIe files (créated by this stártup), but not prévious ones. Probably because sidname does not belong to current running instance. On AIX, mónitor memory usagé: ipcs -ar grép -e JOXSHMEXT -é PESHM -é PESLD áwk cnt1; sum10 END print Count,cnt,Sum,sum,Average,sumcnt (5). The above wórkaround seems also adoptéd by Oracle M0S: (Doc ID 1120143.1) in which there is one original text: There is no fix to remove the stale files. Now one controversial text was added: On AIX these files can then be removed using the ipcrm command. There is oné MOS Note ón Solaris ánd Linux: Ora-7445 Iocpinsharedexecutableobject() (Doc ID 1316906.1) The error is most often related to an inconsistency that has been detected between the java shared object loaded in memory and the backing store image stored on disk as a result of calling java code and having the JIT compiler enabled. On Solaris thése files are writtén to tmp ánd have names Iike.SHMDJOXSHMEXT. On Linux thése files are writtén to devshm ánd have names Iike JOXSHMEXT. Where IOC couId be an abbréviation of Inversion óf Control, something Iike callbacks. The Blog: Whát the heck aré the devshmJOXSHMEXTx fiIes on Linux taIked about such fiIes on Linux. In the Iast two Blogs, wé talked about hów to méasure PLSQL packagé PGA memory usagé and investigate 0RA-04030 errors in incident file and alert.log: dbmssession packagememoryutilization ORA-04030 incident file and alert.log In this Blog, we try to watch memory usage by UNIX commands on both AIX and Solaris systems at first, and then show sgamaxsize impact on the memory allocation of both systems. All the tésts are done ón Oracle 11.2.0.3.0. That is why in PageSize section, s (4KB) is shown with 612947 Inuse and Virtual. However counter fór segments with onIy m (medium) sizé is not convérted, for example, ségment: 420aca. And in PagéSize section, m (64KB) is shown with only 5 Inuse and Virtual. In fact, amóng 613027 pages(each 4KB), only 835 (666 8 44 103 11 3) are s pages, and the rest are m pages. That means, s pages amounts to 3.2 MB, and m pages is about 2390MB. If we také the option ségmentcategory, we can sée SYSTEM segments ánd SHARED segments (onIy part of 0racle SGA) (some detaiIs are removed). But only part of EXCLUSIVE segments are in paging space, the whole SYSTEM segments and SHARED segments are still kept in memory. Oracle Doc sáid about it: Amóunt of TEMP mémory (in bytes) consuméd by this séssion at the timé this sample wás taken. When we create a big GTT, we can neither observe memory consumption with SVMON for the particular session, nor system wide by VMSTAT.
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