Android应用性能优化

转载请注明出处http://blog.csdn.net/guoyjoe/article/details/18508283


有时我们想知道数据在SGA中的哪个池中,可以用下面的方法计算出各池的内存地址边界。


1、LOG BUFFER池内存地址边界


0x00000060222000 > LOG BUFFER池内存 <0x0000006682B000(0x00000060222000+6609000)


如下计算:
sys@DTRACE> oradebug setmypid
Statement processed.
sys@DTRACE> oradebug ipc
Information written to trace file.
sys@DTRACE> col value for a80
sys@DTRACE>  select value from v$diag_info where name=‘Default Trace File‘;


VALUE
--------------------------------------------------------------------------------
/export/home/oracle/diag/rdbms/dtrace/dtrace/trace/dtrace_ora_4103.trc


Area #2 `Redo Buffers‘ containing Subareas 1-1
  Total size 0000000006609000 Minimum Subarea size 00000000
   Area  Subarea    Shmid      Stable Addr      Actual Addr
      2        1   196612 0x00000060222000 0x00000060222000
                              Subarea size     Segment size
                          0000000006609000 0000000006c00000



2、BUFFER CACHE池内存地址的边界


0x0000000078A22000 > BUFFER CACHE池内存地址 < 0x000000007FBD6000




如下计算:
sys@DTRACE> select min(ba),max(ba) from x$bh;


MIN(BA)          MAX(BA)
---------------- ----------------
0000000078A22000 000000007FBD6000




3、SHARED POOL池内存地址边界


0x93800000> SHARED POOL池内存地址 <0x9bc00000 (0x9b800000+400000)




如下计算:
gyj@DTRACE> alter session set events ‘immediate trace name heapdump level 2‘;


Session altered.


gyj@DTRACE> col value for a80
gyj@DTRACE> select value from v$diag_info where name=‘Default Trace File‘;


VALUE
--------------------------------------------------------------------------------
/export/home/oracle/diag/rdbms/dtrace/dtrace/trace/dtrace_ora_4046.trc




more /export/home/oracle/diag/rdbms/dtrace/dtrace/trace/dtrace_ora_4046.trc
******************************************************
HEAP DUMP heap name="sga heap(1,0)"  desc=0x600551a0
 extent sz=0xfe0 alt=248 het=32767 rec=9 flg=-126 opc=0
 parent=(nil) owner=(nil) nex=(nil) xsz=0x400000 heap=(nil)
 fl2=0x20, nex=(nil), dsxvers=1, dsxflg=0x0
 dsx first ext=0x9a800000
 latch set 1 of 7
 durations disabled for this heap
 reserved granules for root 57 (granule size 4194304)
EXTENT 0 addr=0x93800000
.............................
EXTENT 5 addr=0x9b800000
  Chunk        09b800058 sz=       80    perm      "perm           "  alo=80
  Chunk        09b8000a8 sz=       48  R-freeable  "reserved stoppe"
  Chunk        09b8000d8 sz=   212728  R-free      "               "
  Chunk        09b833fd0 sz=       48  R-freeable  "reserved stoppe"
  Chunk        09b834000 sz=  2763512    perm      "perm           "  alo=2763512
  Chunk        09bad6af8 sz=  1209408    perm      "perm           "  alo=1209408
  Chunk        09bbfdf38 sz=       64    freeable  "KGI Session Sta"
  Chunk        09bbfdf78 sz=       40    freeable  "listener addres"
  Chunk        09bbfdfa0 sz=      128    freeable  "dbgefgHtAddSK-1"
  Chunk        09bbfe020 sz=      136    freeable  "dbgefgHtAddSK-1"
  Chunk        09bbfe0a8 sz=       40    freeable  "plwppwp:PLW_STR"
  Chunk        09bbfe0d0 sz=      160    freeable  "joxs heap      "
  Chunk        09bbfe170 sz=       32    freeable  "PRESENTATION EN"
  Chunk        09bbfe190 sz=     2072    freeable  "PRESENTATION TA"
  Chunk        09bbfe9a8 sz=     1168    freeable  "character set m"
  Chunk        09bbfee38 sz=     4552    freeable  "character set m"
Total heap size    = 25165296


看转储的DUMP日志一个区的大小是: xsz=0x400000



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