00 393216 2 dest
0x00000000 3440647 oracle 600 393216 2 dest
0x00000000 3473416 oracle 600 393216 2 dest
0x00000000 3506185 oracle 600 393216 2 dest
0x00000000 3538954 oracle 600 393216 2 dest
0x00000000 3571723 oracle 600 393216 2 dest
0x05a35eec 4194316 oracle 660 4096 0
0x038880a0 3735567 oracle 755 1079228 0
------ Semaphore Arrays --------
key semid owner perms nsems
0xed251740 622592 oracle 660 154
------ Message Queues --------
key msqid owner perms used-bytes messages
SQL> select * from v$sgainfo;
NAME BYTES RES
-------------------------------- ---------- ---
Fixed SGA Size 1336960 No
Redo Buffers 6094848 No
Buffer Cache Size 79691776 Yes
Shared Pool Size 176160768 Yes
Large Pool Size 4194304 Yes
Java Pool Size 4194304 Yes
Streams Pool Size 4194304 Yes
Shared IO Pool Size 0 Yes
Granule Size 4194304 No
Maximum SGA Size 422670336 No
Startup overhead in Shared Pool 58720256 No
NAME BYTES RES
-------------------------------- ---------- ---
Free SGA Memory Available 146800640
如果shmmax的大小小于SGA设置，那么sga任然可以创建成功，但是会被分配多个共享内存段，但是这个shmmax的大小要有底线，
否则OS资源被耗尽，Process J000 is dead
通常建议shmmax设置大些，把sga限制在一个共享内存段中。
官方文档：
Memory Resources
The resources provided by the UNIX default kernels are often inadequate for a medium or large instance of Oracle Database. The maximum size of a shared memory segment (SHMMAX) and maximum number of semaphores available (SEMMNS) may be too low for Oracle Database recommendations.
由UNIX默认内核提供的资源往往是不足的中型或大型的数据库实例。最大的共享内存段的大小（SHMMAX）和信号量可用的最大数目（SEMMNS）可能太低对Oracle数据库的建议。
On Windows, fewer resources are needed for interprocess communication (IPC), because the Oracle Database relational database management system is thread-based and not process-based. These resources, including shared memory and semaphores, are not adjustable by the user.
?
在Windows中，更少的资源用于进程间通信（IPC）所需要的，因为Oracle数据库的关系型数据库管理
系统是基于线程的而不是进程。这些资源，包括共享内存和信号量，都是用户不可修改的。