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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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