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Oracle Castor Administration

Oracle Castor Administration. Nilo Segura Chinchilla Oracle Support IT/DES CERN. Agenda. Database Service Database Software Database Creation Performance/Tuning Backups Service evolution Q/A. Database Service. Standard CERN disk server Dual CPU, 2Gb memory and RAID 1+0

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Oracle Castor Administration

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  1. Oracle Castor Administration Nilo Segura Chinchilla Oracle Support IT/DES CERN

  2. Agenda • Database Service • Database Software • Database Creation • Performance/Tuning • Backups • Service evolution • Q/A

  3. Database Service • Standard CERN disk server • Dual CPU, 2Gb memory and RAID 1+0 • RDBMS 10.2.0.2 + CPU October 2006 • No one-off patches • Using RMAN for backups (full + incremental) • Enabling change block tracking to reduce load during incremental backup • Patch Set 10.2.0.3 should arrive before Christmas • To be installed in the new Castor DB infrastructure • Some tests with Oracle 11g Alpha.

  4. Database Software: Installation • Use Oracle’s standard(supported) runInstaller • Working on automatic scriptable installations • Rpm wrapper around runInstaller silent script ? • Custom: no spatial, no http, no EM Console • Unix oracle account with gid <> dba • Forces re-link of executables (always good idea..) • Oracle’s Enterprise Management Agent + CERN Lemon system

  5. Database creation I • 8k db block size • 16k for DLF looks o.k.. • spfile (no init.ora files any longer) • Tablespaces : extent management local + segment space management auto + autoextend off • Required for ENABLE ROW MOVEMENT + ALTER TABLE.. SHRINK…. • Automatic undo space management,Temporary tablespaces (tempfiles) • Four to five groups of redo log files, each 400-500Mb approx.

  6. Database creation II • sga_max_target for dynamic adjustment of several oracle caches • db_cache_size, shared_pool_size • pga_aggregate_target • workspace_policy=auto • sga_target disabled • db_cache_advice disabled in production • generates high contention on some internal latches with high load… • …but enabled until we get the right value for db_cache_size

  7. Peformance/Tuning • Most of the performance achieved via application tuning • Change of physical layout (iot,partitions) • Missing indexes (normal & Function based) • Automatic Workload Repository is the main tuning tool • $ORACLE_HOME/rdbms/admin/awrrpt • Top wait events, SQL ordered by consistent gets…

  8. Top 5 Timed Events Avg %Total ~~~~~~~~~~~~~~~~~~ wait Call Event Waits Time (s) (ms) Time WaitClass db file sequential read 1,431,831 4,707 3 50.6 User I/O resmgr:become active 5,045 2,891 573 31.1 Scheduler latch: cache buffers chains 31,616 750 24 8.1 Concurrency CPU time 670 7.2 log file sync 4,226 40 10 0.4 Commit

  9. SQL ordered by Gets DB/Inst: CASTORSG/CASTORSG Snaps: 26112-26113 -> Resources reported for PL/SQL code includes the resources used by all SQL statements called by the code. -> Total Buffer Gets: 184,550,148 -> Captured SQL account for 99.2% of Total Gets CPU Elapsed Buffer Gets Executions per Exec %Total Time (s) Time (s) SQL Id 182,937,840 963 189,966.6 99.1 651.46 6195.24 70hx3aq93qqw0 Module: stager@c2publicsrv03.cern.ch (TNS V1-V3) SELECT /*+ INDEX (CastorFile) INDEX (DiskCopy) INDEX (FileSystem) INDEX (DiskSer ver) INDEX (SubRequest) */ UNIQUE CASTORFILE.FILEID, CASTORFILE.NSHOST, DISKCOPY .ID, DISKCOPY.PATH, CASTORFILE.FILESIZE, NVL(DISKCOPY.STATUS, DECODE(SUBREQUEST. STATUS, 0,2, 3,2, -1)), DISKSERVER.NAME, FILESYSTEM.MOUNTPOINT, CASTORFILE.NBACC 31,837 2,889 11.0 0.0 0.81 2.66 2usn5f6wbc75r Module: stager@c2publicsrv03.cern.ch (TNS V1-V3) DELETE FROM Id2Type WHERE id = :1 24,780 1,180 21.0 0.0 0.50 1073.30 gn88ssqqfgtrv Module: stager@c2publicsrv03.cern.ch (TNS V1-V3) UPDATE SubRequest SET status = 3 WHERE (decode(status,0,status,1,status,2,statu s,NULL)) < 3 AND ROWNUM < 2 AND (SELECT type FROM Id2Type WHERE id = SubRequest. request) IN (35, 36, 119, 40, 37, 44, 38, 42, 95, 39) RETURNING id, retryCounter , fileName, protocol, xsize, priority, status, modeBits, flags INTO :1, :2, :3,

  10. LSegments by Logical Reads DB/Inst: CASTORSG/CASTORSG Snaps: 26112-26113 -> Total Logical Reads: 184,550,148 -> Captured Segments account for 99.5% of Total Tablespace Obj. Logical Owner Name Object Name Type Reads %Total CASTOR_STA STAGER_DAT SYS_C0015152 INDEX 46,968,912 25.45 CASTOR_STA STAGER_DAT SYS_C0015149 INDEX 46,965,456 25.45 CASTOR_STA STAGER_DAT SYS_C0015150 INDEX 30,657,792 16.61 CASTOR_STA STAGER_DAT SYS_C0015179 INDEX 15,050,080 8.16 CASTOR_STA STAGER_DAT SYS_C0015151 INDEX 14,613,504 7.92 Segments by Physical Reads DB/Inst: CASTORSG/CASTORSG Snaps: 26112-26113 -> Total Physical Reads: 1,441,997 -> Captured Segments account for 100.2% of Total Tablespace Obj. Physical Owner Name Object Name Type Reads %Total CASTOR_STA STAGER_DAT SUBREQUEST TABLE 738,205 51.19 CASTOR_STA STAGER_DAT STAGEPREPARETOGETREQ TABLE 432,335 29.98 CASTOR_STA STAGER_DAT STAGEGETREQUEST TABLE 243,535 16.89 CASTOR_STA STAGER_DAT CASTORFILE TABLE 13,454 .93 CASTOR_STA STAGER_DAT I_SUBREQUEST_CASTORF INDEX 6,458 .45

  11. Perf&Tuning: Statistics • Froze DB statistics once we were happy with the results • Disabled automatic DB statistics gathering • To avoid unpleasant changes in the execution plans • Moved statistics from one DB to another to obtain same execution plans • Neither system nor Dictionary statistics • To be added later on (needs testing)

  12. Perf&Tuning:Things we tested… • Resource Manager : bad… • Caused database locks up when the activity was high (not possible to login) • Online table redefinition : good… • Useful to change physical table structure or remove the fragmentation of key tables

  13. Perf&Tuning: Problems • DISKCOPY/SUBREQUESTs tables are the weakest point in the chain.. • Experiments Denial of service attacks (aka ooops!) can cause huge increase in their size • Tables become Emmental cheese (holes due to deletes) • High Water Mark does not move, index space not properly reused due to the use of sequences • Require regular de-fragmentation • DBMS_REDEFINITION for online reorganization • Do not use alter table move + alter table rebuild (only if you stop the Stagers first)

  14. Perf&Tuning: Problems • Application deadlocks cause sessions to be killed • Being addressed by the Castor Dev team • Emphasizes the importance of keeping up with current Castor releases • Require installation of hot fixes

  15. Perf&Tuning: Added problem • We (DB support team) do not know the Castor logic • More difficult for us to be helpful… • Can only offer improvements based on what it is written • But real optimized solution could mean to change the algorithm logic!!! • It is crucial to have close ties with the Castor Dev team

  16. Perf&Tuning: Working on… • Adding missing DB constraints • KEEP/RECYCLE buffer cache feature • Uniforms size extents in tablespaces • PL/SQL Native compilation (enabled in Test instance) • Further improvements on physical table layout • IOT, Partitioning, Cluster already applied to some tables • Materializev views for some quasi-static joins (filesystem,diskserver,diskpool2svclass) • PL/SQL code profiling

  17. Service evolution • Moving to Oracle certified RAC hardware (host + storage) on Red Hat Enterprise Edition 4 64bits • 2 Dual Core CPU + 8Gb memory • NAS storage (RAC certified filesystem) • No need of ASM :) • Expected to be in production 1Q07

  18. And now for something completely different… Questions? (ask first, shoot later)

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