{"id":2300,"date":"2026-01-29T14:29:39","date_gmt":"2026-01-29T12:29:39","guid":{"rendered":"https:\/\/www.ludovicocaldara.net\/dba\/?p=2300"},"modified":"2026-01-29T14:29:39","modified_gmt":"2026-01-29T12:29:39","slug":"dg26ai-lag-type","status":"publish","type":"post","link":"https:\/\/www.ludovicocaldara.net\/dba\/dg26ai-lag-type\/","title":{"rendered":"Data Guard 26ai &#8211; #3: Choice of Lag Type for Fast-Start Failover"},"content":{"rendered":"<p><span class=\"\"><a href=\"https:\/\/www.ludovicocaldara.net\/dba\/dg-26ai-series\/\">This post is part of a blog series.<\/a><\/span><\/p>\n<p><span class=\"\">In <\/span><span class=\"\">Data <\/span><span class=\"\">Guard, <\/span><span class=\"\">when <\/span><span class=\"\">Fast-Start <\/span><span class=\"\">Failover <\/span><span class=\"\">runs <\/span><span class=\"\">in <\/span><span class=\"\">Maximum <\/span><span class=\"\">Performance <\/span><span class=\"\">mode, <\/span><span class=\"\">the <\/span><span class=\"\">FSFP <\/span><span class=\"\">process <\/span><span class=\"\">tracks <\/span><span class=\"\">lag <\/span><span class=\"\">to <\/span><span class=\"\">keep <\/span><span class=\"\">the <\/span><span class=\"\">primary <\/span><span class=\"\">database <\/span><span class=\"\">within <\/span><span class=\"\">safe <\/span><span class=\"\">limits.<\/span><br \/>\n<span class=\"\">Traditionally, <\/span><span class=\"\">FSFP <\/span><span class=\"\">used <\/span><span class=\"\">APPLY <\/span><span class=\"\">LAG <\/span><span class=\"\">to <\/span><span class=\"\">measure <\/span><span class=\"\">lag, <\/span><span class=\"\">a <\/span><span class=\"\">legacy <\/span><span class=\"\">from <\/span><span class=\"\">older <\/span><span class=\"\">redo <\/span><span class=\"\">transport. <\/span><span class=\"\">But <\/span><span class=\"\">APPLY <\/span><span class=\"\">LAG <\/span><span class=\"\">may <\/span><span class=\"\">not <\/span><span class=\"\">reflect <\/span><span class=\"\">real <\/span><span class=\"\">data <\/span><span class=\"\">loss <\/span><span class=\"\">risk: TRANSPORT <\/span><span class=\"\">LAG <\/span><span class=\"\">shows <\/span><span class=\"\">how <\/span><span class=\"\">much <\/span><span class=\"\">data <\/span><span class=\"\">hasn&#8217;t <\/span><span class=\"\">reached <\/span><span class=\"\">the <\/span><span class=\"\">standby.<\/span><br \/>\n<span class=\"\">With <\/span><span class=\"\">26ai, <\/span><span class=\"\">you <\/span><span class=\"\">can <\/span><span class=\"\">set <\/span><a href=\"https:\/\/docs.oracle.com\/en\/database\/oracle\/oracle-database\/26\/dgbkr\/faststartfailoverlagtype.html\"><span class=\"\">FastStartFailoverLagType <\/span><\/a><span class=\"\">to <\/span><span class=\"\">APPLY <\/span><span class=\"\">(default) <\/span><span class=\"\">or <\/span><span class=\"\">TRANSPORT.<\/span><br \/>\n<span class=\"\">Consider <\/span><span class=\"\">switching <\/span><span class=\"\">this <\/span><span class=\"\">property <\/span><span class=\"\">to <\/span><span class=\"\">TRANSPORT <\/span><span class=\"\">to <\/span><span class=\"\">track real data loss exposure<\/span><span class=\"\">.<\/span><\/p>\n<p><a href=\"https:\/\/www.ludovicocaldara.net\/dba\/wp-content\/uploads\/2026\/01\/dg26ai-apply-lag-type-scaled.png\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-large wp-image-2306\" src=\"https:\/\/www.ludovicocaldara.net\/dba\/wp-content\/uploads\/2026\/01\/dg26ai-apply-lag-type-1024x203.png\" alt=\"a table shows that before 26ai &quot;APPLY&quot; is the only lag type, while in 26ai it can also be TRANSPORT.\" width=\"584\" height=\"116\" srcset=\"https:\/\/www.ludovicocaldara.net\/dba\/wp-content\/uploads\/2026\/01\/dg26ai-apply-lag-type-1024x203.png 1024w, https:\/\/www.ludovicocaldara.net\/dba\/wp-content\/uploads\/2026\/01\/dg26ai-apply-lag-type-300x59.png 300w, https:\/\/www.ludovicocaldara.net\/dba\/wp-content\/uploads\/2026\/01\/dg26ai-apply-lag-type-768x152.png 768w, https:\/\/www.ludovicocaldara.net\/dba\/wp-content\/uploads\/2026\/01\/dg26ai-apply-lag-type-1536x305.png 1536w, https:\/\/www.ludovicocaldara.net\/dba\/wp-content\/uploads\/2026\/01\/dg26ai-apply-lag-type-2048x406.png 2048w, https:\/\/www.ludovicocaldara.net\/dba\/wp-content\/uploads\/2026\/01\/dg26ai-apply-lag-type-500x99.png 500w\" sizes=\"auto, (max-width: 584px) 100vw, 584px\" \/><\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>With 26ai, you can set FastStartFailoverLagType to APPLY (default) or TRANSPORT to track data loss exposure. <a href=\"https:\/\/www.ludovicocaldara.net\/dba\/dg26ai-lag-type\/\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[375,329],"tags":[],"class_list":["post-2300","post","type-post","status-publish","format-standard","hentry","category-oracle-ai-database-26ai","category-oracle-dg"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.ludovicocaldara.net\/dba\/wp-json\/wp\/v2\/posts\/2300","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ludovicocaldara.net\/dba\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ludovicocaldara.net\/dba\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ludovicocaldara.net\/dba\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ludovicocaldara.net\/dba\/wp-json\/wp\/v2\/comments?post=2300"}],"version-history":[{"count":4,"href":"https:\/\/www.ludovicocaldara.net\/dba\/wp-json\/wp\/v2\/posts\/2300\/revisions"}],"predecessor-version":[{"id":2394,"href":"https:\/\/www.ludovicocaldara.net\/dba\/wp-json\/wp\/v2\/posts\/2300\/revisions\/2394"}],"wp:attachment":[{"href":"https:\/\/www.ludovicocaldara.net\/dba\/wp-json\/wp\/v2\/media?parent=2300"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ludovicocaldara.net\/dba\/wp-json\/wp\/v2\/categories?post=2300"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ludovicocaldara.net\/dba\/wp-json\/wp\/v2\/tags?post=2300"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}