{"id":4177,"date":"2021-04-29T08:48:38","date_gmt":"2021-04-29T08:48:38","guid":{"rendered":"https:\/\/swiv.com.br\/rman-precompression-block-processing\/"},"modified":"2026-05-27T20:02:32","modified_gmt":"2026-05-27T19:02:32","slug":"rman-precompression-block-processing","status":"publish","type":"post","link":"https:\/\/swiv.com.br\/index.php\/2021\/04\/29\/rman-precompression-block-processing\/","title":{"rendered":"RMAN Precompression Block Processing"},"content":{"rendered":"<p>Segundo a documenta\u00e7\u00e3o da Oracle sobre este assunto em espec\u00edfico (link <a rel=\"\\&quot;noreferrer noopener\" noopener=\"\" href=\"https:\/\/docs.oracle.com\/cd\/E11882_01\/backup.112\/e10642\/rcmconfa.htm#BRADV89466\" target=\"\\&quot;_blank\\&quot;\">AQUI<\/a>), \u00e9 poss\u00edvel atingir uma melhor taxa de compress\u00e3o nos backups executados via RMAN caso o recurso de Precompression Block seja utilizado. Ele realiza uma manobra interna de consolidar os espa\u00e7os livres de cada bloco de dados, marcando-os com bin\u00e1rios em 0. Essa caracter\u00edstica \u00e9 relevante nos ambientes mais vol\u00e1teis, que executam inserts e deletes constantes.<\/p>\n\n\n<p>A op\u00e7\u00e3o &#8220;OPTIMIZE FOR LOAD&#8221; que \u00e9 respons\u00e1vel por controlar este recurso. Seu valor padr\u00e3o est\u00e1 configurado como TRUE, o que significa que o Precompression n\u00e3o est\u00e1 sendo utilizado. Para os casos de habilit\u00e1-lo, basta mudar o valor para FALSE, obviamente sabendo que o processamento no servidor ser\u00e1 um pouco mais exigido.<\/p>\n\n\n\n<p>Para simularmos sua execu\u00e7\u00e3o, configurando o algoritmo de compress\u00e3o do RMAN em BASIC, por\u00e9m sem habilitar o Precompression:<\/p>\n\n\n<div class=\"wp-block-syntaxhighlighter-code \\&quot;wp-block-syntaxhighlighter-code\\&quot;\"><pre class=\"brush: plain; title: ; notranslate\" title=\"\">\n&#x5B;oracle@oel8 ~]$ rman target \/\n \nRecovery Manager: Release 18.0.0.0.0 - Production on Thu Apr 29 05:47:14 2021\nVersion 18.13.0.0.0\n \nCopyright (c) 1982, 2018, Oracle and\/or its affiliates.  All rights reserved.\n \nconnected to target database: RMANDB (DBID=3825250984)\n \nRMAN&gt; SHOW COMPRESSION ALGORITHM;\n \nusing target database control file instead of recovery catalog\nRMAN configuration parameters for database with db_unique_name RMANDB are:\nCONFIGURE COMPRESSION ALGORITHM &#039;BASIC&#039; AS OF RELEASE &#039;DEFAULT&#039; OPTIMIZE FOR LOAD TRUE ; # default\n<\/pre><\/div>\n\n\n<p>Backup do banco e seus dados:<\/p>\n\n\n<div class=\"wp-block-syntaxhighlighter-code \\&quot;wp-block-syntaxhighlighter-code\\&quot;\"><pre class=\"brush: plain; title: ; notranslate\" title=\"\">\nRMAN&gt; BACKUP DATABASE;\n \nStarting backup at 2021-04-29:05:16:40\nusing channel ORA_DISK_1\nchannel ORA_DISK_1: starting full datafile backup set\nchannel ORA_DISK_1: specifying datafile(s) in backup set\ninput datafile file number=00001 name=\/oracle\/dados\/RMANDB\/datafile\/o1_mf_system_h8nynqfx_.dbf\ninput datafile file number=00003 name=\/oracle\/dados\/RMANDB\/datafile\/o1_mf_sysaux_h8nyq35q_.dbf\ninput datafile file number=00004 name=\/oracle\/dados\/RMANDB\/datafile\/o1_mf_undotbs1_h8nyrjdr_.dbf\ninput datafile file number=00005 name=\/oracle\/dados\/RMANDB\/datafile\/ts_cortex_catalog.dbf\ninput datafile file number=00007 name=\/oracle\/dados\/RMANDB\/datafile\/o1_mf_users_h8nyrkn7_.dbf\nchannel ORA_DISK_1: starting piece 1 at 2021-04-29:05:16:40\nchannel ORA_DISK_1: finished piece 1 at 2021-04-29:05:16:56\npiece handle=\/oracle\/fra\/RMANDB\/backupset\/2021_04_29\/o1_mf_nnndf_TAG20210429T051640_j8ntv90s_.bkp tag=TAG20210429T051640 comment=NONE\nchannel ORA_DISK_1: backup set complete, elapsed time: 00:00:16\nFinished backup at 2021-04-29:05:16:56\n \nStarting Control File and SPFILE Autobackup at 2021-04-29:05:16:56\npiece handle=\/oracle\/fra\/RMANDB\/autobackup\/2021_04_29\/o1_mf_s_1071119816_j8ntvrkl_.bkp comment=NONE\nFinished Control File and SPFILE Autobackup at 2021-04-29:05:16:57\n \nRMAN&gt; LIST BACKUP OF DATABASE;\n \n \nList of Backup Sets\n===================\n \n \nBS Key  Type LV Size       Device Type Elapsed Time Completion Time\n------- ---- -- ---------- ----------- ------------ -------------------\n246     Full    1.22G      DISK        00:00:09     2021-04-29:05:16:49\n        BP Key: 246   Status: AVAILABLE  Compressed: NO  Tag: TAG20210429T051640\n        Piece Name: \/oracle\/fra\/RMANDB\/backupset\/2021_04_29\/o1_mf_nnndf_TAG20210429T051640_j8ntv90s_.bkp\n  List of Datafiles in backup set 246\n  File LV Type Ckp SCN    Ckp Time            Abs Fuz SCN Sparse Name\n  ---- -- ---- ---------- ------------------- ----------- ------ ----\n  1       Full 2505025    2021-04-29:05:16:40              NO    \/oracle\/dados\/RMANDB\/datafile\/o1_mf_system_h8nynqfx_.dbf\n  3       Full 2505025    2021-04-29:05:16:40              NO    \/oracle\/dados\/RMANDB\/datafile\/o1_mf_sysaux_h8nyq35q_.dbf\n  4       Full 2505025    2021-04-29:05:16:40              NO    \/oracle\/dados\/RMANDB\/datafile\/o1_mf_undotbs1_h8nyrjdr_.dbf\n  5       Full 2505025    2021-04-29:05:16:40              NO    \/oracle\/dados\/RMANDB\/datafile\/ts_cortex_catalog.dbf\n  7       Full 2505025    2021-04-29:05:16:40              NO    \/oracle\/dados\/RMANDB\/datafile\/o1_mf_users_h8nyrkn7_.dbf\n<\/pre><\/div>\n\n\n<p>Alterando algoritmo de compress\u00e3o do RMAN para HIGH, sem habilitar o precompression:<\/p>\n\n\n<div class=\"wp-block-syntaxhighlighter-code \\&quot;wp-block-syntaxhighlighter-code\\&quot;\"><pre class=\"brush: plain; title: ; notranslate\" title=\"\">\nRMAN&gt; SHOW COMPRESSION ALGORITHM;\n \nusing target database control file instead of recovery catalog\nRMAN configuration parameters for database with db_unique_name RMANDB are:\nCONFIGURE COMPRESSION ALGORITHM &#039;HIGH&#039; AS OF RELEASE &#039;DEFAULT&#039; OPTIMIZE FOR LOAD TRUE;\n<\/pre><\/div>\n\n\n<p>Backup e informa\u00e7\u00f5es:<\/p>\n\n\n<div class=\"wp-block-syntaxhighlighter-code \\&quot;wp-block-syntaxhighlighter-code\\&quot;\"><pre class=\"brush: plain; title: ; notranslate\" title=\"\">\nRMAN&gt; BACKUP AS COMPRESSED BACKUPSET DATABASE;\n \nStarting backup at 2021-04-29:05:36:40\nusing channel ORA_DISK_1\nchannel ORA_DISK_1: starting compressed full datafile backup set\nchannel ORA_DISK_1: specifying datafile(s) in backup set\ninput datafile file number=00001 name=\/oracle\/dados\/RMANDB\/datafile\/o1_mf_system_h8nynqfx_.dbf\ninput datafile file number=00003 name=\/oracle\/dados\/RMANDB\/datafile\/o1_mf_sysaux_h8nyq35q_.dbf\ninput datafile file number=00004 name=\/oracle\/dados\/RMANDB\/datafile\/o1_mf_undotbs1_h8nyrjdr_.dbf\ninput datafile file number=00005 name=\/oracle\/dados\/RMANDB\/datafile\/ts_cortex_catalog.dbf\ninput datafile file number=00007 name=\/oracle\/dados\/RMANDB\/datafile\/o1_mf_users_h8nyrkn7_.dbf\nchannel ORA_DISK_1: starting piece 1 at 2021-04-29:05:36:40\nchannel ORA_DISK_1: finished piece 1 at 2021-04-29:05:38:35\npiece handle=\/oracle\/fra\/RMANDB\/backupset\/2021_04_29\/o1_mf_nnndf_TAG20210429T053640_j8nw0r7r_.bkp tag=TAG20210429T053640 comment=NONE\nchannel ORA_DISK_1: backup set complete, elapsed time: 00:01:55\nFinished backup at 2021-04-29:05:38:35\n \nStarting Control File and SPFILE Autobackup at 2021-04-29:05:38:35\npiece handle=\/oracle\/fra\/RMANDB\/autobackup\/2021_04_29\/o1_mf_s_1071121115_j8nw4cn8_.bkp comment=NONE\nFinished Control File and SPFILE Autobackup at 2021-04-29:05:38:36\n \nRMAN&gt; LIST BACKUP OF DATABASE;\n \n \nList of Backup Sets\n===================\n \n \nBS Key  Type LV Size       Device Type Elapsed Time Completion Time\n------- ---- -- ---------- ----------- ------------ -------------------\n256     Full    294.33M    DISK        00:01:45     2021-04-29:05:38:25\n        BP Key: 256   Status: AVAILABLE  Compressed: YES  Tag: TAG20210429T053640\n        Piece Name: \/oracle\/fra\/RMANDB\/backupset\/2021_04_29\/o1_mf_nnndf_TAG20210429T053640_j8nw0r7r_.bkp\n  List of Datafiles in backup set 256\n  File LV Type Ckp SCN    Ckp Time            Abs Fuz SCN Sparse Name\n  ---- -- ---- ---------- ------------------- ----------- ------ ----\n  1       Full 2506811    2021-04-29:05:36:40              NO    \/oracle\/dados\/RMANDB\/datafile\/o1_mf_system_h8nynqfx_.dbf\n  3       Full 2506811    2021-04-29:05:36:40              NO    \/oracle\/dados\/RMANDB\/datafile\/o1_mf_sysaux_h8nyq35q_.dbf\n  4       Full 2506811    2021-04-29:05:36:40              NO    \/oracle\/dados\/RMANDB\/datafile\/o1_mf_undotbs1_h8nyrjdr_.dbf\n  5       Full 2506811    2021-04-29:05:36:40              NO    \/oracle\/dados\/RMANDB\/datafile\/ts_cortex_catalog.dbf\n  7       Full 2506811    2021-04-29:05:36:40              NO    \/oracle\/dados\/RMANDB\/datafile\/o1_mf_users_h8nyrkn7_.dbf\n<\/pre><\/div>\n\n\n<p>Habilitando o recurso de Precompression:<\/p>\n\n\n<div class=\"wp-block-syntaxhighlighter-code \\&quot;wp-block-syntaxhighlighter-code\\&quot;\"><pre class=\"brush: plain; title: ; notranslate\" title=\"\">\nRMAN&gt; CONFIGURE COMPRESSION ALGORITHM &#039;HIGH&#039; AS OF RELEASE &#039;DEFAULT&#039; OPTIMIZE FOR LOAD FALSE;\n \nold RMAN configuration parameters:\nCONFIGURE COMPRESSION ALGORITHM &#039;HIGH&#039; AS OF RELEASE &#039;DEFAULT&#039; OPTIMIZE FOR LOAD TRUE;\nnew RMAN configuration parameters:\nCONFIGURE COMPRESSION ALGORITHM &#039;HIGH&#039; AS OF RELEASE &#039;DEFAULT&#039; OPTIMIZE FOR LOAD FALSE;\nnew RMAN configuration parameters are successfully stored\n<\/pre><\/div>\n\n\n<p>Realizando backup e coletando informa\u00e7\u00f5es:<\/p>\n\n\n<div class=\"wp-block-syntaxhighlighter-code \\&quot;wp-block-syntaxhighlighter-code\\&quot;\"><pre class=\"brush: plain; title: ; notranslate\" title=\"\">\n&#x5B;oracle@oel8 ~]$ rman target \/\n \nRecovery Manager: Release 18.0.0.0.0 - Production on Thu Apr 29 05:40:11 2021\nVersion 18.13.0.0.0\n \nCopyright (c) 1982, 2018, Oracle and\/or its affiliates.  All rights reserved.\n \nconnected to target database: RMANDB (DBID=3825250984)\n \nRMAN&gt; BACKUP AS COMPRESSED BACKUPSET DATABASE;\n \nStarting backup at 2021-04-29:05:40:15\nusing target database control file instead of recovery catalog\nallocated channel: ORA_DISK_1\nchannel ORA_DISK_1: SID=69 device type=DISK\nchannel ORA_DISK_1: starting compressed full datafile backup set\nchannel ORA_DISK_1: specifying datafile(s) in backup set\ninput datafile file number=00001 name=\/oracle\/dados\/RMANDB\/datafile\/o1_mf_system_h8nynqfx_.dbf\ninput datafile file number=00003 name=\/oracle\/dados\/RMANDB\/datafile\/o1_mf_sysaux_h8nyq35q_.dbf\ninput datafile file number=00004 name=\/oracle\/dados\/RMANDB\/datafile\/o1_mf_undotbs1_h8nyrjdr_.dbf\ninput datafile file number=00005 name=\/oracle\/dados\/RMANDB\/datafile\/ts_cortex_catalog.dbf\ninput datafile file number=00007 name=\/oracle\/dados\/RMANDB\/datafile\/o1_mf_users_h8nyrkn7_.dbf\nchannel ORA_DISK_1: starting piece 1 at 2021-04-29:05:40:16\nchannel ORA_DISK_1: finished piece 1 at 2021-04-29:05:42:11\npiece handle=\/oracle\/fra\/RMANDB\/backupset\/2021_04_29\/o1_mf_nnndf_TAG20210429T054015_j8nw7j61_.bkp tag=TAG20210429T054015 comment=NONE\nchannel ORA_DISK_1: backup set complete, elapsed time: 00:01:55\nFinished backup at 2021-04-29:05:42:11\n \nStarting Control File and SPFILE Autobackup at 2021-04-29:05:42:11\npiece handle=\/oracle\/fra\/RMANDB\/autobackup\/2021_04_29\/o1_mf_s_1071121331_j8nwc3qd_.bkp comment=NONE\nFinished Control File and SPFILE Autobackup at 2021-04-29:05:42:12\n \nRMAN&gt; LIST BACKUP OF DATABASE;\n \n \nList of Backup Sets\n===================\n \n \nBS Key  Type LV Size       Device Type Elapsed Time Completion Time\n------- ---- -- ---------- ----------- ------------ -------------------\n258     Full    238.70M    DISK        00:01:47     2021-04-29:05:42:03\n        BP Key: 258   Status: AVAILABLE  Compressed: YES  Tag: TAG20210429T054015\n        Piece Name: \/oracle\/fra\/RMANDB\/backupset\/2021_04_29\/o1_mf_nnndf_TAG20210429T054015_j8nw7j61_.bkp\n  List of Datafiles in backup set 258\n  File LV Type Ckp SCN    Ckp Time            Abs Fuz SCN Sparse Name\n  ---- -- ---- ---------- ------------------- ----------- ------ ----\n  1       Full 2507015    2021-04-29:05:40:16              NO    \/oracle\/dados\/RMANDB\/datafile\/o1_mf_system_h8nynqfx_.dbf\n  3       Full 2507015    2021-04-29:05:40:16              NO    \/oracle\/dados\/RMANDB\/datafile\/o1_mf_sysaux_h8nyq35q_.dbf\n  4       Full 2507015    2021-04-29:05:40:16              NO    \/oracle\/dados\/RMANDB\/datafile\/o1_mf_undotbs1_h8nyrjdr_.dbf\n  5       Full 2507015    2021-04-29:05:40:16              NO    \/oracle\/dados\/RMANDB\/datafile\/ts_cortex_catalog.dbf\n  7       Full 2507015    2021-04-29:05:40:16              NO    \/oracle\/dados\/RMANDB\/datafile\/o1_mf_users_h8nyrkn7_.dbf\n<\/pre><\/div>\n\n\n<p>A taxa de compress\u00e3o foi um pouco maior no \u00faltimo exemplo, mesmo considerando que meu banco de laborat\u00f3rio n\u00e3o tem caracter\u00edstica de sofrer muitos deletes e inserts, e possuir um tamanho muito menor que os bancos corporativos. Mas j\u00e1 podemos ter uma no\u00e7\u00e3o da diferen\u00e7a que este recurso pode prover, logicamente sendo aplicado com crit\u00e9rio e cuidado em nossos ambientes.<\/p>\n\n\n\n<p>Obs: Este procedimento foi criado pelo senhor Ahmed Baraka (www.ahmedbaraka.com) e foi apenas reproduzido por mim em um laborat\u00f3rio pessoal para fins de aprendizado.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Segundo a documenta\u00e7\u00e3o da Oracle sobre este assunto em espec\u00edfico (link AQUI), \u00e9 poss\u00edvel atingir uma melhor taxa de compress\u00e3o nos backups executados via RMAN caso o recurso de Precompression Block seja utilizado. Ele realiza uma manobra interna de consolidar os espa\u00e7os livres de cada bloco de dados, marcando-os com bin\u00e1rios em 0. Essa caracter\u00edstica [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"class_list":["post-4177","post","type-post","status-publish","format-standard","hentry","category-backup-recovery"],"_links":{"self":[{"href":"https:\/\/swiv.com.br\/index.php\/wp-json\/wp\/v2\/posts\/4177","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/swiv.com.br\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/swiv.com.br\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/swiv.com.br\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/swiv.com.br\/index.php\/wp-json\/wp\/v2\/comments?post=4177"}],"version-history":[{"count":1,"href":"https:\/\/swiv.com.br\/index.php\/wp-json\/wp\/v2\/posts\/4177\/revisions"}],"predecessor-version":[{"id":9155,"href":"https:\/\/swiv.com.br\/index.php\/wp-json\/wp\/v2\/posts\/4177\/revisions\/9155"}],"wp:attachment":[{"href":"https:\/\/swiv.com.br\/index.php\/wp-json\/wp\/v2\/media?parent=4177"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/swiv.com.br\/index.php\/wp-json\/wp\/v2\/categories?post=4177"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/swiv.com.br\/index.php\/wp-json\/wp\/v2\/tags?post=4177"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}