{"id":11046,"date":"2018-03-27T14:37:55","date_gmt":"2018-03-27T12:37:55","guid":{"rendered":"https:\/\/www.dbi-services.com\/blog\/the-wal-segement-size-becomes-changeable-in-postgresql-11\/"},"modified":"2018-03-27T14:37:55","modified_gmt":"2018-03-27T12:37:55","slug":"the-wal-segement-size-becomes-changeable-in-postgresql-11","status":"publish","type":"post","link":"https:\/\/www.dbi-services.com\/blog\/the-wal-segement-size-becomes-changeable-in-postgresql-11\/","title":{"rendered":"The WAL segment size becomes changeable in PostgreSQL 11"},"content":{"rendered":"<p>Up to PostgreSQL 10 the wal segment size was fixed once PostgreSQL was compiled and installed. When you wanted to have something else than the default you needed to tell that to the configure command when building from source, e.g.<\/p>\n<pre class=\"brush: bash; gutter: true; first-line: 1\">\npostgres@pgbox:\/home\/postgres\/postgresql\/ [PGDEV] .\/configure --with-wal-segsize=64MB\n<\/pre>\n<p>For PostgreSQL 11 two commits landed (<a href=\"https:\/\/git.postgresql.org\/gitweb\/?p=postgresql.git;a=commit;h=fc49e24fa69a15efacd5b8958115ed9c43c48f9a\" target=\"_blank\" rel=\"noopener\">1<\/a> and <a href=\"https:\/\/git.postgresql.org\/gitweb\/?p=postgresql.git;a=commit;h=bf4a8676c316c177f395b54d3305ea4ccc838a66\" target=\"_blank\" rel=\"noopener\">2<\/a>) which change this. Lets have a look.<\/p>\n<p><!--more--><\/p>\n<p>When you check the <a href=\"https:\/\/www.postgresql.org\/docs\/devel\/static\/app-initdb.html\" target=\"_blank\" rel=\"noopener\">current development documentation for initdb<\/a> you&#8217;ll notice a new parameter called &#8220;&#8211;wal-segsize&#8221;. This allows to change the WAL segment size from the default of 16MB when you initialize you new cluster:<\/p>\n<pre class=\"brush: bash; gutter: true; first-line: 1; highlight: [1]\">\npostgres@pgbox:\/home\/postgres\/ [PGDEV] initdb --wal-segsize=32 \/var\/tmp\/aa\nThe files belonging to this database system will be owned by user \"postgres\".\nThis user must also own the server process.\n\nThe database cluster will be initialized with locales\n  COLLATE:  en_US.utf8\n  CTYPE:    en_US.utf8\n  MESSAGES: en_US.utf8\n  MONETARY: de_CH.UTF-8\n  NUMERIC:  de_CH.UTF-8\n  TIME:     en_US.UTF-8\nThe default database encoding has accordingly been set to \"UTF8\".\nThe default text search configuration will be set to \"english\".\n\nData page checksums are disabled.\n\ncreating directory \/var\/tmp\/aa ... ok\ncreating subdirectories ... ok\nselecting default max_connections ... 100\nselecting default shared_buffers ... 128MB\nselecting dynamic shared memory implementation ... posix\ncreating configuration files ... ok\nrunning bootstrap script ... ok\nperforming post-bootstrap initialization ... ok\nsyncing data to disk ... ok\n\nWARNING: enabling \"trust\" authentication for local connections\nYou can change this by editing pg_hba.conf or using the option -A, or\n--auth-local and --auth-host, the next time you run initdb.\n\nSuccess. You can now start the database server using:\n\n    pg_ctl -D \/var\/tmp\/aa -l logfile start\n<\/pre>\n<p>Btw: You can also use <a href=\"https:\/\/www.postgresql.org\/docs\/devel\/static\/app-pgcontroldata.html\" target=\"_blank\" rel=\"noopener\">pg_controldata<\/a> to get the size of the WAL segments:<\/p>\n<pre class=\"brush: bash; gutter: true; first-line: 1\">\npostgres@pgbox:\/home\/postgres\/ [PGDEV] pg_controldata | grep \"Bytes per WAL segment\"\nBytes per WAL segment:                33554432\npostgres@pgbox:\/home\/postgres\/ [PGDEV] echo \"33554432\/1024\/1024\" | bc\n32\n<\/pre>\n<p>The other commit added the same option to <a href=\"https:\/\/www.postgresql.org\/docs\/devel\/static\/app-pgresetwal.html\" target=\"_blank\" rel=\"noopener\">pg_resetwal<\/a>. <\/p>\n<pre class=\"brush: bash; gutter: true; first-line: 1\">\npostgres@pgbox:\/home\/postgres\/ [PGDEV] pg_resetwal -D \/var\/tmp\/aa\/ --wal-segsize=64\nWrite-ahead log reset\npostgres@pgbox:\/home\/postgres\/ [PGDEV] pg_controldata | grep \"Bytes per WAL segment\"\nBytes per WAL segment:                67108864\npostgres@pgbox:\/home\/postgres\/ [PGDEV] echo \"67108864\/1024\/1024\" | bc\n64\n<\/pre>\n<p>So, hopefully this September when PostgreSQL 11 should be released, you do not need to install additional binaries for changing the WAL segment size. This will also allow major upgrades with pg_upgrade to a new cluster with a different WAL segment size. Nice, makes things easier.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Up to PostgreSQL 10 the wal segment size was fixed once PostgreSQL was compiled and installed. When you wanted to have something else than the default you needed to tell that to the configure command when building from source, e.g. postgres@pgbox:\/home\/postgres\/postgresql\/ [PGDEV] .\/configure &#8211;with-wal-segsize=64MB For PostgreSQL 11 two commits landed (1 and 2) which change [&hellip;]<\/p>\n","protected":false},"author":29,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[229],"tags":[77],"type_dbi":[],"class_list":["post-11046","post","type-post","status-publish","format-standard","hentry","category-database-administration-monitoring","tag-postgresql"],"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>The WAL segment size becomes changeable in PostgreSQL 11 - dbi Blog<\/title>\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\/the-wal-segement-size-becomes-changeable-in-postgresql-11\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"The WAL segment size becomes changeable in PostgreSQL 11\" \/>\n<meta property=\"og:description\" content=\"Up to PostgreSQL 10 the wal segment size was fixed once PostgreSQL was compiled and installed. When you wanted to have something else than the default you needed to tell that to the configure command when building from source, e.g. postgres@pgbox:\/home\/postgres\/postgresql\/ [PGDEV] .\/configure --with-wal-segsize=64MB For PostgreSQL 11 two commits landed (1 and 2) which change [&hellip;]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.dbi-services.com\/blog\/the-wal-segement-size-becomes-changeable-in-postgresql-11\/\" \/>\n<meta property=\"og:site_name\" content=\"dbi Blog\" \/>\n<meta property=\"article:published_time\" content=\"2018-03-27T12:37:55+00:00\" \/>\n<meta name=\"author\" content=\"Daniel Westermann\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:creator\" content=\"@westermanndanie\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Daniel Westermann\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"2 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\/\/www.dbi-services.com\/blog\/the-wal-segement-size-becomes-changeable-in-postgresql-11\/#article\",\"isPartOf\":{\"@id\":\"https:\/\/www.dbi-services.com\/blog\/the-wal-segement-size-becomes-changeable-in-postgresql-11\/\"},\"author\":{\"name\":\"Daniel Westermann\",\"@id\":\"https:\/\/www.dbi-services.com\/blog\/#\/schema\/person\/8d08e9bd996a89bd75c0286cbabf3c66\"},\"headline\":\"The WAL segment size becomes changeable in PostgreSQL 11\",\"datePublished\":\"2018-03-27T12:37:55+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\/\/www.dbi-services.com\/blog\/the-wal-segement-size-becomes-changeable-in-postgresql-11\/\"},\"wordCount\":168,\"commentCount\":0,\"keywords\":[\"PostgreSQL\"],\"articleSection\":[\"Database Administration &amp; Monitoring\"],\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"CommentAction\",\"name\":\"Comment\",\"target\":[\"https:\/\/www.dbi-services.com\/blog\/the-wal-segement-size-becomes-changeable-in-postgresql-11\/#respond\"]}]},{\"@type\":\"WebPage\",\"@id\":\"https:\/\/www.dbi-services.com\/blog\/the-wal-segement-size-becomes-changeable-in-postgresql-11\/\",\"url\":\"https:\/\/www.dbi-services.com\/blog\/the-wal-segement-size-becomes-changeable-in-postgresql-11\/\",\"name\":\"The WAL segment size becomes changeable in PostgreSQL 11 - dbi Blog\",\"isPartOf\":{\"@id\":\"https:\/\/www.dbi-services.com\/blog\/#website\"},\"datePublished\":\"2018-03-27T12:37:55+00:00\",\"author\":{\"@id\":\"https:\/\/www.dbi-services.com\/blog\/#\/schema\/person\/8d08e9bd996a89bd75c0286cbabf3c66\"},\"breadcrumb\":{\"@id\":\"https:\/\/www.dbi-services.com\/blog\/the-wal-segement-size-becomes-changeable-in-postgresql-11\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/www.dbi-services.com\/blog\/the-wal-segement-size-becomes-changeable-in-postgresql-11\/\"]}]},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/www.dbi-services.com\/blog\/the-wal-segement-size-becomes-changeable-in-postgresql-11\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Accueil\",\"item\":\"https:\/\/www.dbi-services.com\/blog\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"The WAL segment size becomes changeable in PostgreSQL 11\"}]},{\"@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\/8d08e9bd996a89bd75c0286cbabf3c66\",\"name\":\"Daniel Westermann\",\"image\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/secure.gravatar.com\/avatar\/31350ceeecb1dd8986339a29bf040d4cd3cd087d410deccd8f55234466d6c317?s=96&d=mm&r=g\",\"url\":\"https:\/\/secure.gravatar.com\/avatar\/31350ceeecb1dd8986339a29bf040d4cd3cd087d410deccd8f55234466d6c317?s=96&d=mm&r=g\",\"contentUrl\":\"https:\/\/secure.gravatar.com\/avatar\/31350ceeecb1dd8986339a29bf040d4cd3cd087d410deccd8f55234466d6c317?s=96&d=mm&r=g\",\"caption\":\"Daniel Westermann\"},\"description\":\"Daniel Westermann is Principal Consultant and Technology Leader Open Infrastructure at dbi services. He has more than 15 years of experience in management, engineering and optimization of databases and infrastructures, especially on Oracle and PostgreSQL. Since the beginning of his career, he has specialized in Oracle Technologies and is Oracle Certified Professional 12c and Oracle Certified Expert RAC\/GridInfra. Over time, Daniel has become increasingly interested in open source technologies, becoming \u201cTechnology Leader Open Infrastructure\u201d and PostgreSQL expert. \u00a0Based on community or EnterpriseDB tools, he develops and installs complex high available solutions with PostgreSQL. He is also a certified PostgreSQL Plus 9.0 Professional and a Postgres Advanced Server 9.4 Professional. He is a regular speaker at PostgreSQL conferences in Switzerland and Europe. Today Daniel is also supporting our customers on AWS services such as AWS RDS, database migrations into the cloud, EC2 and automated infrastructure management with AWS SSM (System Manager). He is a certified AWS Solutions Architect Professional. Prior to dbi services, Daniel was Management System Engineer at LC SYSTEMS-Engineering AG in Basel. Before that, he worked as Oracle Developper &amp;\u00a0Project Manager at Delta Energy Solutions AG in Basel (today Powel AG). Daniel holds a diploma in Business Informatics (DHBW, Germany). His branch-related experience mainly covers the pharma industry, the financial sector, energy, lottery and telecommunications.\",\"sameAs\":[\"https:\/\/x.com\/westermanndanie\"],\"url\":\"https:\/\/www.dbi-services.com\/blog\/author\/daniel-westermann\/\"}]}<\/script>\n<!-- \/ Yoast SEO Premium plugin. -->","yoast_head_json":{"title":"The WAL segment size becomes changeable in PostgreSQL 11 - dbi Blog","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\/the-wal-segement-size-becomes-changeable-in-postgresql-11\/","og_locale":"en_US","og_type":"article","og_title":"The WAL segment size becomes changeable in PostgreSQL 11","og_description":"Up to PostgreSQL 10 the wal segment size was fixed once PostgreSQL was compiled and installed. 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He has more than 15 years of experience in management, engineering and optimization of databases and infrastructures, especially on Oracle and PostgreSQL. Since the beginning of his career, he has specialized in Oracle Technologies and is Oracle Certified Professional 12c and Oracle Certified Expert RAC\/GridInfra. Over time, Daniel has become increasingly interested in open source technologies, becoming \u201cTechnology Leader Open Infrastructure\u201d and PostgreSQL expert. \u00a0Based on community or EnterpriseDB tools, he develops and installs complex high available solutions with PostgreSQL. He is also a certified PostgreSQL Plus 9.0 Professional and a Postgres Advanced Server 9.4 Professional. He is a regular speaker at PostgreSQL conferences in Switzerland and Europe. Today Daniel is also supporting our customers on AWS services such as AWS RDS, database migrations into the cloud, EC2 and automated infrastructure management with AWS SSM (System Manager). He is a certified AWS Solutions Architect Professional. Prior to dbi services, Daniel was Management System Engineer at LC SYSTEMS-Engineering AG in Basel. Before that, he worked as Oracle Developper &amp;\u00a0Project Manager at Delta Energy Solutions AG in Basel (today Powel AG). Daniel holds a diploma in Business Informatics (DHBW, Germany). His branch-related experience mainly covers the pharma industry, the financial sector, energy, lottery and telecommunications.","sameAs":["https:\/\/x.com\/westermanndanie"],"url":"https:\/\/www.dbi-services.com\/blog\/author\/daniel-westermann\/"}]}},"_links":{"self":[{"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/posts\/11046","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\/29"}],"replies":[{"embeddable":true,"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/comments?post=11046"}],"version-history":[{"count":0,"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/posts\/11046\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/media?parent=11046"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/categories?post=11046"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/tags?post=11046"},{"taxonomy":"type","embeddable":true,"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/type_dbi?post=11046"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}