Shulou(Shulou.com)05/31 Report--

The main content of this article is "how to understand the performance of Iripple O". Interested friends may wish to take a look. The method introduced in this paper is simple, fast and practical. Let's let the editor take you to learn "how to understand the performance of Iripple O".

In order to understand the performance of Icano, you must have a detailed understanding of the storage hierarchy of the stored files. Oracle provides a set of dynamic performance depending on the country to display the mapping information from the file to the middle tier of the logical volume to the actual physical device. Using these dynamic performance views, you can find the actual physical disk built into any block of data in a file. The Oracle database uses a background process called FMON to manage mapping information. Oracle provides the PL/SQL dbms_storage_map package to populate the mapping operation into the mapping view. Oracle database file mapping does not require the use of third-party dynamic libraries when mapping Oracle ASM files. In addition, the Oracle database supports mapping Oracle ASM files on all operating system platforms.

Enable file mapping for Oracle ASM files

To enable file mapping, the parameter file_mapping needs to be set to true. The database instance does not have to be closed to set this parameter. You can set this parameter using the following alter system statement:

SQL > alter system set file_mapping=true scope=both sid='*';System altered.

Perform the appropriate dbms_storage_map mapping process

. In the case of a cold start, no mapping operation is invoked when the Oracle database is just started. You can execute the dbms_storage_map.map_all procedure to build mapping information for the entire database-related Imax O subsystem. For example, the following command builds the mapping information and provides the 10000 event:

SQL > execute dbms_storage_map.map_all (10000); PL/SQL procedure successfully completed.

. In the case of warm startup, the Oracle database has built the mapping information, and you can choose to execute the dbms_storage_map.map_save process to save the mapping information in the data dictionary. By default, this procedure will be called by the dbms_storage_map.map_all procedure, which forces all mapping information in SGA to be flushed to disk. By default, the dbms_storage_map.map_save procedure will be dbms_storage_map.map_all (). After restarting the database, use the dbms_storage_map.restore () procedure to restore the mapping information to SGA. Dbms_storage_map.map_all () can be used to refresh the mapping information if needed.

The mapping information generated by the dbms_storage_map package is captured in the dynamic performance view. These views include the vicious mappings compounding listings, recording mappings, listing, recording, mapping, recording, recording, mapping, mapping, filewriting, listing, listing, recording, mapping, mapping, filewriting, mapping, listing, listing, recording, mapping, mapping, listing, mapping, listing, listing, mapping, listing, recording, mapping, mapping, listing, and, v$map_subelement.

You can use v$map_file to query file mapping information:

SQL > select file_map_idx, substr (file_name,1,45), file_type, file_structure from v$map_file FILE_MAP_IDX SUBSTR (FILE_NAME 1pc45) FILE_TYPE FILE_STRU-- -0 + DATA/CS/DATAFILE/system.272.970601831 DATAFILE ASMFILE 1 + DATA/CS/DATAFILE/sysaux.273.970601881 DATAFILE ASMFILE 2 + DATA/CS/DATAFILE/undotbs1.274.970601905 DATAFILE ASMFILE 3 + DATA/CS/4700A987085B3DFAE05387E5E50A8C7B/DAT DATAFILE ASMFILE 4 + DATA/CS/4700A987085B3DFAE05387E5E50A8C7B/DAT DATAFILE ASMFILE 5 + DATA/CS/DATAFILE/users.275.970601909 DATAFILE ASMFILE 6 + DATA/CS/4700A987085B3DFAE05387E5E50A8C7B/DAT DATAFILE ASMFILE 7 + DATA/CS/DATAFILE/undotbs2.284 .970602381 DATAFILE ASMFILE 8 + DATA/CS/DATAFILE/test.326.976211663 DATAFILE ASMFILE 9 + DATA/CS/DATAFILE/jy.331.976296525 DATAFILE ASMFILE 10 + DATA/CS/6C61AD7B443C2CD2E053BE828A0A2A74/DAT DATAFILE ASMFILE 11 + DATA/CS/6C61AD7B443C2CD2E053BE828A0A2A74/DAT DATAFILE ASMFILE 12 + DATA/CS/6C61AD7B443C2CD2E053BE828A0A2A74/DAT DATAFILE ASMFILE 13 + DATA/CS/ONLINELOG/group_2.277.970601985 LOGFILE ASMFILE 14 + DATA/CS/ONLINELOG/group_1.278.970601985 LOGFILE ASMFILE 15 + DATA/CS/ONLINELOG/group_3.285.970602759 LOGFILE ASMFILE 16 + DATA/CS/ONLINELOG/group_4.286.970602761 LOGFILE ASMFILE 17 + DATA/CS/ONLINELOG/redo05.log LOGFILE ASMFILE 18 + DATA/CS / ONLINELOG/redo06.log LOGFILE ASMFILE 19 + DATA/CS/ONLINELOG/redo07.log LOGFILE ASMFILE 20 + DATA/CS/ONLINELOG/redo08.log LOGFILE ASMFILE 21 + DATA/CS/ONLINELOG/redo09.log LOGFILE ASMFILE 22 + DATA/CS/ONLINELOG/redo10.log LOGFILE ASMFILE 23 + DATA/CS / TEMPFILE/temp.279.970602003 TEMPFILE ASMFILE 24 + DATA/CS/67369AA1C9AA3E71E053BE828A0A8262/TEM TEMPFILE ASMFILE 25 + DATA/CS/6C61AD7B443C2CD2E053BE828A0A2A74/TEM TEMPFILE ASMFILE 26 + DATA/arch / 1_222_970601983.dbf ARCHIVEFILE ASMFILE 27 + DATA/arch/1_223_970601983.dbf ARCHIVEFILE ASMFILE 28 + DATA/arch/2_277_970601983.dbf ARCHIVEFILE ASMFILE 29 + DATA/arch/2_278_970601983.dbf ARCHIVEFILE ASMFILE 30 + DATA/arch/2_279_970601983.dbf ARCHIVEFILE ASMFILE 31 + DATA/CS / CONTROLFILE/current.276.970601979 CONTROLFILE ASMFILE31 rows selected.

You can use the procedures in the dbms_storage_map PL/SQL package to control the mapping operation. For example, you can use the dbms_storage_map.map_object procedure to build mapping information against database objects by specifying the object name, owner, and type. After the dbms_storage_map.map_object process runs, you can query the mapping information by querying the map_object view

SQL > execute dbms_storage_map.map_object ('T _ 1','T _ 1', T _ 1, T _ 1, T, etc.) PL/SQL procedure successfully completed.SQL > select io.object_name o_name, io.object_owner o_owner, io.object_type o_type, 2 mf.file_name, me.elem_name, io.depth, 3 (sum (io.cu_size * (io.num_cu-decode (io.parity_period, 0,0,4 trunc (io.num_cu / io.parity_period) / 2) o_size 5 from map_object io, v$map_element me V$map_file mf 6 where io.object_name = 'T17 and io.object_owner =' C##TEST'and io.object_type = 'TABLE' 8 9 and me.elem_idx = io.elem_idx 10 and mf.file_map_idx = io.file_map_idx 11 group by io.elem_idx, io.file_map_idx, me.elem_name, mf.file_name, io.depth, 12 io.object_name, io.object_owner, io.object_type 13 order by io.depth O_NAME O_OWNER O_TYP FILE_NAME ELEM_NAME DEPTH Odyssey-- -T1 C##TEST TABLE + DATA/CS/DATAFILE/users.275.970601909 + / dev/asmdisk04 0 64 to this I believe that you have a deeper understanding of "how to understand the performance of Ithumb O". You might as well do it in practice. Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.