Explanation of memory block SGA and background processes in oracle (sqlplus) and sgasqlplus

Explanation of memory block SGA and background processes in oracle (sqlplus) and sgasqlplus

Oracle has a large memory block called the system global zone (SGA). here it will do the following:

Maintain various internal data structures that all processes need to access

Cache data on the disk, and cache data here before redoing data to the disk

Save resolved SQL plans

And so on.

Oralce has a group of processes "appended to" SAGde, And the attaching mechanism is only for the operating system.

In windows, these processes only use the C call (malloc) to allocate memory. Because they are actually threads in a large process, they will share the same virtual memory space. Oralce also has a set of files for the database process/thread to read and write (only the oralce process can read and write these files ). These files store all the table data, indexes, temporary space, and redo logs.

The oracle background processes constitute the persistent processes of the instance. Starting from the instance, these processes will continue to run until the instance is closed.

Note that these are processes, not individual programs. There is only one binary executable file, that is, oracle.

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Download pstools, decompress pstools.zip, and run pslist.exe.

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Solution: copy the pslist.exe file to the C: \ Windows \ System32 directory.

Verify: Enter the command line and enter pslist:

C:\Users\Administrator>pslistPsList v1.4 - Process information listerCopyright (C) 2000-2016 Mark RussinovichSysinternals - www.sysinternals.comProcess information for 20180314-120628:Name                Pid Pri Thd  Hnd   Priv        CPU Time    Elapsed TimeIdle                  0   0   4    0      0    24:50:24.047     6:26:57.402System                4   8 139  705    124     0:03:20.757     6:26:57.402smss                296  11   3   32    700     0:00:00.093     6:26:57.324csrss               508  13   9  723   2716     0:00:02.558     6:26:51.910wininit             636  13   3   86   1964     0:00:00.140     6:26:50.616csrss               656  13  13  999   4052     0:00:18.220     6:26:50.600services            692   9   5  245   6024     0:00:01.622     6:26:50.506lsass               716   9   8  787   5676     0:00:05.226     6:26:50.460lsm                 724   8  10  155   2640     0:00:00.046     6:26:50.460svchost             820   8  11  391   4896     0:00:03.946     6:26:49.914nvvsvc              880   8   4  122   3112     0:00:00.109     6:26:49.789svchost             920   8  11  371   5144     0:00:00.811     6:26:49.773svchost             984   8  23  575  24888     0:00:04.243     6:26:49.742svchost            1016   8  20  474 125612     0:01:11.744     6:26:49.711svchost             336   8  24  708  14216     0:00:01.107     6:26:49.695svchost             516   8  34 1268  23428     0:00:03.541     6:26:49.680winlogon            768  13   3  114   3452     0:00:00.265     6:26:49.383igfxCUIService     1136   8   6  122   2608     0:00:00.062     6:26:48.244svchost            1204   8  17  495  15148     0:00:05.366     6:26:48.198nvxdsync           1388   8  13  292  12812     0:00:04.118     6:26:47.137spoolsv            1644   8  19  396  24084     0:00:00.265     6:26:46.022svchost            1676   8  18  325  15308     0:00:01.528     6:26:46.002armsvc             1804   8   4   77   1264     0:00:00.015     6:26:45.742svchost            1828   8  10  148   3672     0:00:00.046     6:26:45.282IMEDICTUPDATE      1892   8   4   62   1632     0:00:00.000     6:26:44.882oracle             2044   8  31  652 1128724     0:00:26.629     6:26:42.942OSPPSVC            1128   8   3  155   6260     0:00:05.148     6:26:41.732QQProtect          1752   8  20  370  15900     0:00:01.092     6:26:33.132Service_KMS        1760   8   8  482  25864     0:00:00.967     6:26:31.682TeamViewer_Service  2008   8  19  364   5156     0:00:00.577     6:26:30.636WmiPrvSE           2408   8   6  214   6900     0:00:00.405     6:26:06.503dwm                2688  13   5  156  35240     0:01:18.889     6:26:02.650explorer           2744   8  36 1203  56432     0:00:28.470     6:26:02.619taskhost           2780   8  13  291  30576     0:00:03.712     6:26:02.588PresentationFontCache  2936   8   6  156  26684     0:00:00.156     6:26:01.433rundll32           2968   8   3   79   2212     0:00:00.015     6:26:01.355RAVCpl64           1484   8  11  266   9184     0:00:00.156     6:26:00.934RAVBg64            2324   8  10  209  15096     0:00:00.078     6:26:00.903RAVBg64            2576   8  10  204  15100     0:00:00.109     6:26:00.887YunDetectService   3128   8  15  198   5640     0:00:00.109     6:26:00.435TSVNCache          3468   8  25  112   4204     0:00:00.202     6:25:57.985jusched            3740   8   2   87   2332     0:00:00.015     6:25:54.556WmiPrvSE           3800   8   6  128   3616     0:00:00.078     6:25:53.889svchost            3952   8   6   97   1924     0:00:00.046     6:25:53.530svchost            4000   8   5  102   2568     0:00:00.078     6:25:53.515SearchIndexer      1300   8  14  894  50588     0:00:20.030     6:25:52.142igfxEM             3200   8   5  129   4588     0:00:00.124     6:25:51.814wmpnetwk           3516   8   9  282   8532     0:00:05.428     6:25:51.752igfxHK             3908   8   7  288  11644     0:00:00.249     6:25:51.533igfxTray           3764   8   4  114   3888     0:00:00.062     6:25:51.533svchost            4128   8  19  342   7292     0:00:16.239     6:25:50.363bee                5060   8  71 1375 106664     0:00:31.449     6:24:15.078bee.worker         5112   8  10  274  63416     0:00:49.935     6:23:48.364bee.worker         2372   8  10  180  33672     0:00:01.014     6:23:46.674OUTLOOK            2716   8  43 4505 128100     0:00:32.370     6:23:06.948idea64             1600   8  39  761 1016380     0:07:52.277     6:22:34.805fsnotifier64       4100   8   4   28   3828     0:00:04.305     6:21:59.924conhost            3704   8   1   36   1716     0:00:00.015     6:21:59.924chrome              996   8  44 1514  76576     0:02:16.110     6:21:05.199chrome             1332   8   7  109   2808     0:00:00.015     6:21:04.963chrome             3044   8   2   66   3200     0:00:00.046     6:21:04.074chrome             1376   8  20  303  96184     0:02:50.446     6:21:03.154SogouCloud         3732   8  22  288  11588     0:00:35.693     6:14:57.895taskhost           5760   8   6  231   7432     0:00:00.140     6:11:40.326rundll32           1692   8   2  119   3352     0:00:00.062     6:03:15.150chrome             6732   4  18  386 189812     0:03:41.521     5:43:45.876AcroRd32           3604   8  11  276   9212     0:00:01.934     5:41:29.087AcroRd32           6320   8  18  445 148364     0:00:15.241     5:41:28.116cmd                4624   8   1   25   2312     0:00:00.015     5:38:22.396conhost            5116   8   2   64   2260     0:00:01.482     5:38:22.336java               6808   8  13  317  79604     0:00:02.542     4:37:03.609conhost            6724   8   1   37   1716     0:00:00.015     4:37:03.600navicat            5524   8   3  201  15616     0:00:11.481     2:17:32.728uedit64            5956   8  11  210  48388     0:00:03.868     0:10:41.103chrome             2840   4  16  232  43636     0:00:03.525     0:10:10.922chrome             7136   4  18  250  60104     0:00:08.470     0:09:56.386chrome             6604   4  16  245  46376     0:00:02.605     0:09:04.193chrome             3280   8  24  381  82884     0:00:24.507     0:08:01.450audiodg            3476   8   6  146  17164     0:00:00.514     0:04:09.356SGTool             6680   8  15  392  10972     0:00:02.667     0:03:30.078SGPicFaceTool      2672   8  21  295   5320     0:00:00.062     0:01:31.659pslist             5000  13   1  164   2576     0:00:00.093     0:00:00.125

Pslist nameDisplay process information with the specified name, for example, pslist oracle

C:\Users\Administrator>pslist oraclePsList v1.4 - Process information listerCopyright (C) 2000-2016 Mark RussinovichSysinternals - www.sysinternals.comProcess information for 20180314-120628:Name                Pid Pri Thd  Hnd   Priv        CPU Time    Elapsed Timeoracle             2044   8  31  654 1128740     0:00:29.343     7:05:24.242

This oracle process has 19 threads (the Thd column shown above). You can also use pslist to view more details about each thread:

C:\Users\Administrator>pslist -d oraclePsList v1.4 - Process information listerCopyright (C) 2000-2016 Mark RussinovichSysinternals - www.sysinternals.comThread detail for 20180314-120628:oracle 2044: Tid Pri    Cswtch            State     User Time   Kernel Time   Elapsed Time 352   9       170     Wait:UserReq  0:00:00.031   0:00:00.093    7:49:47.6361060   8         8     Wait:UserReq  0:00:00.000   0:00:00.000    7:49:47.1361104   9       287     Wait:UserReq  0:00:00.187   0:00:00.062    7:49:47.1261228  10        11     Wait:UserReq  0:00:00.000   0:00:00.000    7:49:45.5011480   8     26595     Wait:UserReq  0:00:00.031   0:00:00.000    7:49:39.2771448  15   2119637   Wait:DelayExec  0:00:00.000   0:00:00.015    7:49:39.2611468   8     23621     Wait:UserReq  0:00:00.015   0:00:00.000    7:49:39.2461476   8     38570     Wait:UserReq  0:00:00.000   0:00:00.000    7:49:39.2301472   8     19605     Wait:UserReq  0:00:00.000   0:00:00.000    7:49:39.2301444   8     22768     Wait:UserReq  0:00:00.015   0:00:00.031    7:49:39.2301464   8     66808     Wait:UserReq  0:00:00.624   0:00:00.015    7:49:39.2151456   8     24398     Wait:UserReq  0:00:00.031   0:00:00.015    7:49:39.2151548   8     33397     Wait:UserReq  0:00:00.156   0:00:00.093    7:49:39.2151588   8     33704     Wait:UserReq  0:00:00.234   0:00:00.156    7:49:39.1991596   9     85007     Wait:UserReq  0:00:00.577   0:00:00.546    7:49:39.1991592   8     19276     Wait:UserReq  0:00:00.530   0:00:00.124    7:49:39.1991608   8     12189     Wait:UserReq  0:00:00.000   0:00:00.000    7:49:39.1831612   8     45782     Wait:UserReq  0:00:00.655   0:00:00.187    7:49:39.1831616   8    109049     Wait:UserReq  0:00:00.062   0:00:00.015    7:49:39.1831704   8     18566     Wait:UserReq  0:00:00.015   0:00:00.000    7:49:39.1681708   8     12453     Wait:UserReq  0:00:00.031   0:00:00.015    7:49:39.168 156  11       520       Wait:Queue  0:00:00.000   0:00:00.000    7:49:38.0132264   8     14156     Wait:UserReq  0:00:00.000   0:00:00.000    7:49:23.4122340   8     27361     Wait:UserReq  0:00:00.780   0:00:00.015    7:49:14.9252344   8     16580     Wait:UserReq  0:00:00.015   0:00:00.000    7:49:13.3502352   9     13742     Wait:UserReq  0:00:00.015   0:00:00.000    7:49:13.3343692   8     34862     Wait:UserReq  0:00:00.015   0:00:00.000    7:44:19.3706660   8       354       Wait:Queue  0:00:00.000   0:00:00.000    6:10:44.0625628   8       134     Wait:UserReq  0:00:00.015   0:00:00.000    0:02:58.5836020   8        92     Wait:UserReq  0:00:00.015   0:00:00.000    0:00:20.6984828   8        86     Wait:UserReq  0:00:00.000   0:00:00.000    0:00:20.698

Pslist

-D: The display thread is obvious;

-M: The memory size is obvious;

-T displays the process tree;

-X displays process, memory, and thread details;

Name: displays information about the specified process;

-E precisely matches the specified process name;