{"id":2101,"date":"2011-01-03T14:10:00","date_gmt":"2011-01-03T13:10:00","guid":{"rendered":"https:\/\/www.dbi-services.com\/blog\/problem-strange-figures-while-collecting-the-oracle-optimizer-system-statistics\/"},"modified":"2011-01-03T14:10:00","modified_gmt":"2011-01-03T13:10:00","slug":"problem-strange-figures-while-collecting-the-oracle-optimizer-system-statistics","status":"publish","type":"post","link":"https:\/\/www.dbi-services.com\/blog\/problem-strange-figures-while-collecting-the-oracle-optimizer-system-statistics\/","title":{"rendered":"How to avoid strange figures in the Oracle optimizer system statistics"},"content":{"rendered":"<p>Have you ever noticed strange figures while collecting the Oracle optimizer system statistics ? If so, you need to provide the optimizer with the correct number, as explained in this posting.<br \/>\nMess in the System statistics with Oracle 11.2: while collecting the system statistics during 30 minutes on an Oracle 11.2.0.1 database on Linux&#8230;<\/p>\n<p><samp>exec dbms_stats.gather_system_stats (gathering_mode =&gt; &#8216;interval&#8217;,interval =&gt; 30);<\/samp><\/p>\n<p>&#8230;we get really strange results in the system stats table:<\/p>\n<pre class=\"brush: sql; gutter: true; first-line: 1\">SQL&gt; select * from sys.aux_stats$;\n\nSNAME\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 PNAME\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 PVAL1 PVAL2\n------------------- ------------------------------ ---------- -------------------\nSYSSTATS_INFO\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 STATUS\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 COMPLETED\nSYSSTATS_INFO\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 DSTART\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 07-07-2010 16:35\nSYSSTATS_INFO\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 DSTOP\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 07-07-2010 17:05\nSYSSTATS_MAIN\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SREADTIM\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 17204.089 &lt;==== in ms !!\nSYSSTATS_MAIN\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 MREADTIM\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 20661.538 &lt;==== in ms !!\nSREADTIM - single block read time : 17204 miliseconds\nMREADTIM - single block read time : 20661 miliseconds<\/pre>\n<p>An acceptable value for a single block read (SREADTIM) is about 2 to 6 ms. A little bit higher for Multi block reads.<\/p>\n<p>If your applications suffers from this bug (9842771 and 9701256), a workaround will be to set the values to acceptable ranges, for instance 4 ms for a single access and 10 ms for a multi block access :<\/p>\n<p><samp>exec dbms_stats.set_system_stats(pname =&gt;&#8217;sreadtim&#8217;, pvalue =&gt;4);<br \/>\nexec dbms_stats.set_system_stats(pname =&gt;&#8217;mreadtim&#8217;, pvalue =&gt;10);<\/samp><\/p>\n<p>Now, as a last step, you just need to verify:<\/p>\n<pre class=\"brush: sql; gutter: true; first-line: 1\">SQL&gt; select * from sys.aux_stats$;\nSNAME\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 PNAME\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 PVAL1 PVAL2\n------------------------------ ------------------------------ ---------- ---------\nSYSSTATS_MAIN\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SREADTIM\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 4\nSYSSTATS_MAIN\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 MREADTIM\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 10<\/pre>\n<p>Good luck with collecting your Oracle system statistics!<\/p>\n<p>Best regards,<br \/>\nYann<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Have you ever noticed strange figures while collecting the Oracle optimizer system statistics ? If so, you need to provide the optimizer with the correct number. In this posting, I will show you how.<\/p>\n","protected":false},"author":9,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[197],"tags":[14,15,16,17,18,19,20],"type_dbi":[],"class_list":["post-2101","post","type-post","status-publish","format-standard","hentry","category-application-integration-middleware","tag-i-o","tag-migration","tag-multi-block-read","tag-oracle-11g","tag-oracle-optimizer","tag-single-block-read","tag-system-statistics"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v27.2 (Yoast SEO v27.2) - https:\/\/yoast.com\/product\/yoast-seo-premium-wordpress\/ -->\n<title>How to avoid strange figures in the Oracle optimizer system statistics - dbi Blog<\/title>\n<meta name=\"description\" content=\"This posting will show you how to avoid strange figures in the Oracle optimizer system statistics.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.dbi-services.com\/blog\/problem-strange-figures-while-collecting-the-oracle-optimizer-system-statistics\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"How to avoid strange figures in the Oracle optimizer system statistics\" \/>\n<meta property=\"og:description\" content=\"This posting will show you how to avoid strange figures in the Oracle optimizer system statistics.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.dbi-services.com\/blog\/problem-strange-figures-while-collecting-the-oracle-optimizer-system-statistics\/\" \/>\n<meta property=\"og:site_name\" content=\"dbi Blog\" \/>\n<meta property=\"article:published_time\" content=\"2011-01-03T13:10:00+00:00\" \/>\n<meta name=\"author\" content=\"Yann Neuhaus\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Yann Neuhaus\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"1 minute\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\/\/www.dbi-services.com\/blog\/problem-strange-figures-while-collecting-the-oracle-optimizer-system-statistics\/#article\",\"isPartOf\":{\"@id\":\"https:\/\/www.dbi-services.com\/blog\/problem-strange-figures-while-collecting-the-oracle-optimizer-system-statistics\/\"},\"author\":{\"name\":\"Yann Neuhaus\",\"@id\":\"https:\/\/www.dbi-services.com\/blog\/#\/schema\/person\/5bfc203607127a4915b7950c4a108681\"},\"headline\":\"How to avoid strange figures in the Oracle optimizer system statistics\",\"datePublished\":\"2011-01-03T13:10:00+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\/\/www.dbi-services.com\/blog\/problem-strange-figures-while-collecting-the-oracle-optimizer-system-statistics\/\"},\"wordCount\":180,\"commentCount\":0,\"keywords\":[\"I\/O\",\"Migration\",\"Multi block read\",\"Oracle 11g\",\"Oracle optimizer\",\"Single block read\",\"System statistics\"],\"articleSection\":[\"Application integration &amp; Middleware\"],\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"CommentAction\",\"name\":\"Comment\",\"target\":[\"https:\/\/www.dbi-services.com\/blog\/problem-strange-figures-while-collecting-the-oracle-optimizer-system-statistics\/#respond\"]}]},{\"@type\":\"WebPage\",\"@id\":\"https:\/\/www.dbi-services.com\/blog\/problem-strange-figures-while-collecting-the-oracle-optimizer-system-statistics\/\",\"url\":\"https:\/\/www.dbi-services.com\/blog\/problem-strange-figures-while-collecting-the-oracle-optimizer-system-statistics\/\",\"name\":\"How to avoid strange figures in the Oracle optimizer system statistics - dbi Blog\",\"isPartOf\":{\"@id\":\"https:\/\/www.dbi-services.com\/blog\/#website\"},\"datePublished\":\"2011-01-03T13:10:00+00:00\",\"author\":{\"@id\":\"https:\/\/www.dbi-services.com\/blog\/#\/schema\/person\/5bfc203607127a4915b7950c4a108681\"},\"description\":\"This posting will show you how to avoid strange figures in the Oracle optimizer system statistics.\",\"breadcrumb\":{\"@id\":\"https:\/\/www.dbi-services.com\/blog\/problem-strange-figures-while-collecting-the-oracle-optimizer-system-statistics\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/www.dbi-services.com\/blog\/problem-strange-figures-while-collecting-the-oracle-optimizer-system-statistics\/\"]}]},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/www.dbi-services.com\/blog\/problem-strange-figures-while-collecting-the-oracle-optimizer-system-statistics\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Accueil\",\"item\":\"https:\/\/www.dbi-services.com\/blog\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"How to avoid strange figures in the Oracle optimizer system statistics\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/www.dbi-services.com\/blog\/#website\",\"url\":\"https:\/\/www.dbi-services.com\/blog\/\",\"name\":\"dbi Blog\",\"description\":\"\",\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/www.dbi-services.com\/blog\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-US\"},{\"@type\":\"Person\",\"@id\":\"https:\/\/www.dbi-services.com\/blog\/#\/schema\/person\/5bfc203607127a4915b7950c4a108681\",\"name\":\"Yann Neuhaus\",\"image\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/secure.gravatar.com\/avatar\/d2729b4bbf77b0fe6f6d2b9fb1b2686404c89a16ce2701e860bfd1406212f796?s=96&d=mm&r=g\",\"url\":\"https:\/\/secure.gravatar.com\/avatar\/d2729b4bbf77b0fe6f6d2b9fb1b2686404c89a16ce2701e860bfd1406212f796?s=96&d=mm&r=g\",\"contentUrl\":\"https:\/\/secure.gravatar.com\/avatar\/d2729b4bbf77b0fe6f6d2b9fb1b2686404c89a16ce2701e860bfd1406212f796?s=96&d=mm&r=g\",\"caption\":\"Yann Neuhaus\"},\"url\":\"https:\/\/www.dbi-services.com\/blog\/author\/yann-neuhaus\/\"}]}<\/script>\n<!-- \/ Yoast SEO Premium plugin. -->","yoast_head_json":{"title":"How to avoid strange figures in the Oracle optimizer system statistics - dbi Blog","description":"This posting will show you how to avoid strange figures in the Oracle optimizer system statistics.","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/www.dbi-services.com\/blog\/problem-strange-figures-while-collecting-the-oracle-optimizer-system-statistics\/","og_locale":"en_US","og_type":"article","og_title":"How to avoid strange figures in the Oracle optimizer system statistics","og_description":"This posting will show you how to avoid strange figures in the Oracle optimizer system statistics.","og_url":"https:\/\/www.dbi-services.com\/blog\/problem-strange-figures-while-collecting-the-oracle-optimizer-system-statistics\/","og_site_name":"dbi Blog","article_published_time":"2011-01-03T13:10:00+00:00","author":"Yann Neuhaus","twitter_card":"summary_large_image","twitter_misc":{"Written by":"Yann Neuhaus","Est. reading time":"1 minute"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/www.dbi-services.com\/blog\/problem-strange-figures-while-collecting-the-oracle-optimizer-system-statistics\/#article","isPartOf":{"@id":"https:\/\/www.dbi-services.com\/blog\/problem-strange-figures-while-collecting-the-oracle-optimizer-system-statistics\/"},"author":{"name":"Yann Neuhaus","@id":"https:\/\/www.dbi-services.com\/blog\/#\/schema\/person\/5bfc203607127a4915b7950c4a108681"},"headline":"How to avoid strange figures in the Oracle optimizer system statistics","datePublished":"2011-01-03T13:10:00+00:00","mainEntityOfPage":{"@id":"https:\/\/www.dbi-services.com\/blog\/problem-strange-figures-while-collecting-the-oracle-optimizer-system-statistics\/"},"wordCount":180,"commentCount":0,"keywords":["I\/O","Migration","Multi block read","Oracle 11g","Oracle optimizer","Single block read","System statistics"],"articleSection":["Application integration &amp; Middleware"],"inLanguage":"en-US","potentialAction":[{"@type":"CommentAction","name":"Comment","target":["https:\/\/www.dbi-services.com\/blog\/problem-strange-figures-while-collecting-the-oracle-optimizer-system-statistics\/#respond"]}]},{"@type":"WebPage","@id":"https:\/\/www.dbi-services.com\/blog\/problem-strange-figures-while-collecting-the-oracle-optimizer-system-statistics\/","url":"https:\/\/www.dbi-services.com\/blog\/problem-strange-figures-while-collecting-the-oracle-optimizer-system-statistics\/","name":"How to avoid strange figures in the Oracle optimizer system statistics - dbi Blog","isPartOf":{"@id":"https:\/\/www.dbi-services.com\/blog\/#website"},"datePublished":"2011-01-03T13:10:00+00:00","author":{"@id":"https:\/\/www.dbi-services.com\/blog\/#\/schema\/person\/5bfc203607127a4915b7950c4a108681"},"description":"This posting will show you how to avoid strange figures in the Oracle optimizer system statistics.","breadcrumb":{"@id":"https:\/\/www.dbi-services.com\/blog\/problem-strange-figures-while-collecting-the-oracle-optimizer-system-statistics\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/www.dbi-services.com\/blog\/problem-strange-figures-while-collecting-the-oracle-optimizer-system-statistics\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/www.dbi-services.com\/blog\/problem-strange-figures-while-collecting-the-oracle-optimizer-system-statistics\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Accueil","item":"https:\/\/www.dbi-services.com\/blog\/"},{"@type":"ListItem","position":2,"name":"How to avoid strange figures in the Oracle optimizer system statistics"}]},{"@type":"WebSite","@id":"https:\/\/www.dbi-services.com\/blog\/#website","url":"https:\/\/www.dbi-services.com\/blog\/","name":"dbi Blog","description":"","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/www.dbi-services.com\/blog\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-US"},{"@type":"Person","@id":"https:\/\/www.dbi-services.com\/blog\/#\/schema\/person\/5bfc203607127a4915b7950c4a108681","name":"Yann Neuhaus","image":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/secure.gravatar.com\/avatar\/d2729b4bbf77b0fe6f6d2b9fb1b2686404c89a16ce2701e860bfd1406212f796?s=96&d=mm&r=g","url":"https:\/\/secure.gravatar.com\/avatar\/d2729b4bbf77b0fe6f6d2b9fb1b2686404c89a16ce2701e860bfd1406212f796?s=96&d=mm&r=g","contentUrl":"https:\/\/secure.gravatar.com\/avatar\/d2729b4bbf77b0fe6f6d2b9fb1b2686404c89a16ce2701e860bfd1406212f796?s=96&d=mm&r=g","caption":"Yann Neuhaus"},"url":"https:\/\/www.dbi-services.com\/blog\/author\/yann-neuhaus\/"}]}},"_links":{"self":[{"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/posts\/2101","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/users\/9"}],"replies":[{"embeddable":true,"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/comments?post=2101"}],"version-history":[{"count":0,"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/posts\/2101\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/media?parent=2101"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/categories?post=2101"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/tags?post=2101"},{"taxonomy":"type","embeddable":true,"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/type_dbi?post=2101"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}