{"id":3720,"date":"2025-05-29T17:28:42","date_gmt":"2025-05-29T17:28:42","guid":{"rendered":"https:\/\/w3buddy.com\/?post_type=cposts&#038;p=3720"},"modified":"2025-05-29T17:28:43","modified_gmt":"2025-05-29T17:28:43","slug":"process-monitor-pmon","status":"publish","type":"cposts","link":"https:\/\/w3buddy.com\/blog\/notes\/getting-started-with-oracle-dba\/process-monitor-pmon\/","title":{"rendered":"Process Monitor (PMON)"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">\ud83e\udde0 <strong>What Is PMON?<\/strong><br>The <strong>Process Monitor (PMON)<\/strong> is one of Oracle\u2019s background processes, quietly ensuring that failed processes and sessions are cleaned up properly. It helps maintain the health of the instance by cleaning up after crashes or disconnections.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\ud83e\uddf9 What PMON Does<\/h3>\n\n\n\n<figure class=\"wp-block-table has-small-font-size\"><table><thead><tr><th><strong>Component<\/strong><\/th><th><strong>Description<\/strong><\/th><\/tr><\/thead><tbody><tr><td><strong>PMON<\/strong> \ud83d\udd0d<\/td><td>Scans all processes regularly to detect abnormally terminated sessions. Delegates actual cleanup tasks to CLMN and runs as an OS-level process.<\/td><\/tr><tr><td><strong>CLMN<\/strong> \ud83e\uddfc<\/td><td>The <strong>Cleanup Main Process<\/strong>. Handles the actual cleanup of resources like memory, locks, and session entries.<\/td><\/tr><tr><td><strong>CLnn (Workers)<\/strong> \ud83e\uddd1\u200d\ud83d\udd27<\/td><td><strong>Cleanup Worker Processes<\/strong>. CLMN assigns detailed cleanup tasks (like releasing resources) to these helper processes for efficiency and scalability.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\">\ud83d\udcbb Where PMON Runs<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\ud83d\udee0\ufe0f <strong>Database Instances<\/strong> \u2013 Ensures session\/process cleanup for terminated sessions.<\/li>\n\n\n\n<li>\ud83d\udcbe <strong>Oracle ASM Instances<\/strong> \u2013 Manages resource cleanup related to storage.<\/li>\n\n\n\n<li>\ud83d\udce1 <strong>Oracle ASM Proxy Instances<\/strong> \u2013 Same role as above, but for proxy-managed environments.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">\ud83d\udca1 <strong>DBA Tip of the Day<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">If you notice <strong>hanging sessions<\/strong> or <strong>resource contention<\/strong>, check PMON and related cleanup processes in the diagnostic logs. A sluggish PMON can indicate deeper system-level problems.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\ud83e\udde0 What Is PMON?The Process Monitor (PMON) is one of Oracle\u2019s background processes, quietly ensuring that failed processes and sessions are cleaned up properly. It helps maintain the health of the instance by cleaning up after crashes or disconnections. \ud83e\uddf9 What PMON Does Component Description PMON \ud83d\udd0d Scans all processes regularly to detect abnormally terminated [&hellip;]<\/p>\n","protected":false},"template":"","meta":{"googlesitekit_rrm_CAowu461DA:productID":""},"categories":[960,952],"class_list":["post-3720","cposts","type-cposts","status-publish","hentry","category-getting-started-with-oracle-dba","category-notes"],"_links":{"self":[{"href":"https:\/\/w3buddy.com\/blog\/wp-json\/wp\/v2\/cposts\/3720","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/w3buddy.com\/blog\/wp-json\/wp\/v2\/cposts"}],"about":[{"href":"https:\/\/w3buddy.com\/blog\/wp-json\/wp\/v2\/types\/cposts"}],"wp:attachment":[{"href":"https:\/\/w3buddy.com\/blog\/wp-json\/wp\/v2\/media?parent=3720"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/w3buddy.com\/blog\/wp-json\/wp\/v2\/categories?post=3720"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}