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undersized sga

James ManoharanSep 27 2016 — edited Sep 27 2016

Hello

I see undersized sga in addm report. it's on and off. what size of sga i need to set for this to go away. Any help is apperciated.

thanks

Jim.

here is the deails

Linux6  vm
cpu cores       : 6
MemTotal:       56658028 kB

Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production

Total System Global Area 3.3554E+10 bytes
Fixed Size                  4517232 bytes
Variable Size            5905580688 bytes
Database Buffers         2.7582E+10 bytes
Redo Buffers               62590976 bytes

sga_max_size                 32000M
sga_target                   30016M

SELECT size_for_estimate, buffers_for_estimate, estd_physical_read_factor,
       estd_physical_reads
  FROM V$DB_CACHE_ADVICE
WHERE name = 'DEFAULT'
   AND block_size = (SELECT value FROM V$PARAMETER WHERE name = 'db_block_size')
   AND advice_status = 'ON';SQL> SQL> SQL>   2    3    4    5    6

                                Estd Phys    Estd Phys
Cache Size (MB)      Buffers Read Factor        Reads
---------------- ------------ ----------- ------------
           2,560      315,000        2.85 ############
           5,120      630,000        2.42 ############
           7,680      945,000        2.11 ############
          10,240    1,260,000        1.86 ############
          12,800    1,575,000        1.65 ############
          15,360    1,890,000        1.48  905,386,873
          17,920    2,205,000        1.33  810,958,270
          20,480    2,520,000        1.20  733,667,131
          23,040    2,835,000        1.09  667,013,908
          25,600    3,150,000        1.01  613,595,734

                                Estd Phys    Estd Phys
Cache Size (MB)      Buffers Read Factor        Reads
---------------- ------------ ----------- ------------
          25,792    3,173,625        1.00  610,041,053
          28,160    3,465,000         .94  573,415,830
          30,720    3,780,000         .89  545,584,824
          33,280    4,095,000         .87  528,225,099
          35,840    4,410,000         .85  516,668,461
          38,400    4,725,000         .83  506,735,869
          40,960    5,040,000         .81  496,454,452
          43,520    5,355,000         .80  488,172,867
          46,080    5,670,000         .78  478,466,273
          48,640    5,985,000         .77  471,271,530

                                Estd Phys    Estd Phys
Cache Size (MB)      Buffers Read Factor        Reads
---------------- ------------ ----------- ------------
          51,200    6,300,000         .76  465,457,631

21 rows selected.

1* select * from v$sga_target_advice order by sga_size
SQL> /

                                                               Estd Phys
  SGA_SIZE SGA_SIZE_FACTOR ESTD_DB_TIME ESTD_DB_TIME_FACTOR        Reads ESTD_BUFFER_CACHE_SIZE ESTD_SHARED_POOL_SIZE     CON_ID
---------- --------------- ------------ ------------------- ------------ ---------------------- --------------------- ----------
      3752            .125       462620               .4612  610,084,320                  28160                  2240          0
      7504             .25      2331958              2.3248 ############                   5120                  1600          0
     11256            .375      1982887              1.9768 ############                   7680                  3008          0
     15008              .5      1598306              1.5934 ############                  12800                  1920          0
     18760            .625      1458176              1.4537  963,262,133                  15360                  3328          0
     22512             .75      1223255              1.2195  780,541,879                  20480                  2240          0
     26264            .875      1130671              1.1272  709,650,081                  23040                  3584          0
     30016               1      1003079                   1  610,084,320                  28160                  2240          0
     33768           1.125       963758               .9608  580,495,230                  30720                  3840          0
     37520            1.25       924839                .922  549,685,972                  35840                  2816          0

                                                               Estd Phys
  SGA_SIZE SGA_SIZE_FACTOR ESTD_DB_TIME ESTD_DB_TIME_FACTOR        Reads ESTD_BUFFER_CACHE_SIZE ESTD_SHARED_POOL_SIZE     CON_ID
---------- --------------- ------------ ------------------- ------------ ---------------------- --------------------- ----------
     41272           1.375       910395               .9076  539,131,514                  38400                  4160          0
     45024             1.5       885518               .8828  519,425,790                  43520                  3072          0
     48776           1.625       863149               .8605  501,428,303                  48640                  1920          0
     52528            1.75       853821               .8512  495,205,443                  51200                  3328          0
     56280           1.875       853420               .8508  495,205,443                  51200                  6400          0
     60032               2       853420               .8508  495,205,443                  51200                  6400          0

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