Oracle自动内存管理的几个小问题
1) 开启了自动内存管理之后，如果有pool的值设置为非0值会怎么处理？
比如，设置了sga_target=10G，但是java_pool_size设置为10m，这时，10m会作为java pool的最少分配内存空间。
If these automatically tuned memory pools had been set to nonzero values, those values are used as minimum levels by Automatic Shared Memory Management. You would set minimum values if an application component needs a minimum amount of memory to function properly.
2) 关闭自动管理后，相关pool的值会被自动设置。
If you dynamically disable SGA_TARGET by setting its value to 0 at instance startup, Automatic Shared Memory Management will be disabled and the current auto-tuned sizes will be used for each memory pool.
01 sys@HUA>show parameter memory; 02 03 NAME TYPE VALUE 04 ------------------------------------ ----------- ------------------------------ 05 hi_shared_memory_address integer 0 06 memory_max_target big integer 0 07 memory_target big integer 0 08 shared_memory_address integer 0 09 sys@HUA>show parameter sga 10 11 NAME TYPE VALUE 12 ------------------------------------ ----------- ------------------------------ 13 lock_sga boolean FALSE 14 pre_page_sga boolean FALSE 15 sga_max_size big integer 440M 16 sga_target big integer 440M 17 sys@HUA>alter system set sga_target=0; 18 19 System altered. 20 21 sys@HUA>show parameter pool; 22 23 NAME TYPE VALUE 24 ------------------------------------ ----------- ------------------------------ 25 _shared_io_pool_size big integer 0 26 buffer_pool_keep string 27 buffer_pool_recycle string 28 global_context_pool_size string 29 java_pool_size big integer 4M 30 large_pool_size big integer 8M 31 olap_page_pool_size big integer 0 32 shared_pool_reserved_size big integer 7549747 33 shared_pool_size big integer 208M 34 streams_pool_size big integer 0 35 sys@HUA>alter system set sga_target=440; 36 37 System altered. 38 39 sys@HUA>show parameter pool; 40 41 NAME TYPE VALUE 42 ------------------------------------ ----------- ------------------------------ 43 _shared_io_pool_size big integer 0 44 buffer_pool_keep string 45 buffer_pool_recycle string 46 global_context_pool_size string 47 java_pool_size big integer 4M 48 large_pool_size big integer 8M 49 olap_page_pool_size big integer 0 50 shared_pool_reserved_size big integer 7549747 51 shared_pool_size big integer 208M 52 streams_pool_size big integer 0 53 sys@HUA>alter system set java_pool_size=0; 54 55 System altered. 56 57 sys@HUA>alter system set large_pool_size=0; 58 59 System altered. 60 61 sys@HUA>alter system set shared_pool_size=0; 62 63 System altered. 64 65 sys@HUA> 66 sys@HUA>show parameter pool; 67 68 NAME TYPE VALUE 69 ------------------------------------ ----------- ------------------------------ 70 _shared_io_pool_size big integer 0 71 buffer_pool_keep string 72 buffer_pool_recycle string 73 global_context_pool_size string 74 java_pool_size big integer 0 75 large_pool_size big integer 0 76 olap_page_pool_size big integer 0 77 shared_pool_reserved_size big integer 7549747 78 shared_pool_size big integer 0 79 streams_pool_size big integer 0 80 sys@HUA