{"id":5159,"date":"2015-06-15T12:48:16","date_gmt":"2015-06-15T10:48:16","guid":{"rendered":"https:\/\/www.dbi-services.com\/blog\/what-is-more-efficient-arrays-or-single-column-values\/"},"modified":"2015-06-15T12:48:16","modified_gmt":"2015-06-15T10:48:16","slug":"what-is-more-efficient-arrays-or-single-column-values","status":"publish","type":"post","link":"https:\/\/www.dbi-services.com\/blog\/what-is-more-efficient-arrays-or-single-column-values\/","title":{"rendered":"What is more efficient: arrays or single column values?"},"content":{"rendered":"

In PostgreSQL ( as well as in other rdbms ) you can define columns as arrays. What I wondered is: What is more efficient when it comes to space: Creating several columns or just creating once column as array? The result, at least for me, is rather surprising.<\/p>\n

\"Read<\/p>\n

First, let’s create a table with columns of type int:<\/p>\n

postgres=# create table single_values ( a int, b int, c int, d int, e int, f int, g int, h int, i int, j int );\nCREATE TABLE\npostgres=# \\d single_values\n Table \"public.single_values\"\n Column |  Type   | Modifiers \n--------+---------+-----------\n a      | integer | \n b      | integer | \n c      | integer | \n d      | integer | \n e      | integer | \n f      | integer | \n g      | integer | \n h      | integer | \n i      | integer | \n j      | integer | \n<\/pre>\n
Next create a table with just one column of type array[int]:<\/p>\n
postgres=# create table arr_values ( a int[] );\nCREATE TABLE\n<\/pre>\n
Ready for populating the first table;<\/p>\n
truncate table single_values;\n\\timing on\nTiming is on.\nDO $$DECLARE\n  ln int := 1000;\nBEGIN\n  for i in 0..1e6 loop\n    insert into single_values (a,b,c,d,e,f,g,h,i,j)\n           values (ln,ln,ln,ln,ln,ln,ln,ln,ln,ln);\n  end loop;\nEND$$;\nDO\nTime: 4225.313 ms\npostgres=# \n<\/pre>\n
And the table with the array column:<\/p>\n
truncate table arr_values;\n \\timing on\n Timing is on.\n DO $$DECLARE\n larr int[] := '{1000,1000,1000,1000,1000,1000,1000,1000,1000,1000}';\n BEGIN\n for i in 0..1e6 loop\n insert into arr_values (a)\n values (larr);\n end loop;\n END$$;<\/pre>\n
postgres=# \\i populate_arr_values.sql\n TRUNCATE TABLE\n DO\n Time: 4033.523 ms\n postgres=#<\/pre>\n
Now, what about the size?<\/p>\n
postgres=# select pg_size_pretty(pg_relation_size('single_values'));\n pg_size_pretty \n----------------\n 65 MB\n(1 row)\n\nTime: 0.227 ms\npostgres=# select pg_size_pretty(pg_relation_size('arr_values'));\n pg_size_pretty \n----------------\n 89 MB\n(1 row)\n\nTime: 0.737 ms<\/pre>\n
I did expect the table with the array to be smaller but it is the other way around. The table with the 10 columns is smaller. In the next post I’ll do the same for oracle.<\/p>\n","protected":false},"excerpt":{"rendered":"
In PostgreSQL ( as well as in other rdbms ) you can define columns as arrays. What I wondered is: What is more efficient when it comes to space: Creating several columns or just creating once column as array? The result, at least for me, is rather surprising. First, let’s create a table with columns […]<\/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-5159","post","type-post","status-publish","format-standard","hentry","category-database-administration-monitoring","tag-postgresql"],"acf":[],"yoast_head":"\nWhat is more efficient: arrays or single column values? - 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\/what-is-more-efficient-arrays-or-single-column-values\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"What is more efficient: arrays or single column values?\" \/>\n<meta property=\"og:description\" content=\"In PostgreSQL ( as well as in other rdbms ) you can define columns as arrays. What I wondered is: What is more efficient when it comes to space: Creating several columns or just creating once column as array? The result, at least for me, is rather surprising. First, let’s create a table with columns […]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.dbi-services.com\/blog\/what-is-more-efficient-arrays-or-single-column-values\/\" \/>\n<meta property=\"og:site_name\" content=\"dbi Blog\" \/>\n<meta property=\"article:published_time\" content=\"2015-06-15T10:48:16+00:00\" \/>\n<meta property=\"og:image\" content=\"http:\/\/wwwold.dbi-services.com\/plugins\/editors\/jce\/tiny_mce\/plugins\/article\/img\/trans.gif\" \/>\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\/what-is-more-efficient-arrays-or-single-column-values\/#article\",\"isPartOf\":{\"@id\":\"https:\/\/www.dbi-services.com\/blog\/what-is-more-efficient-arrays-or-single-column-values\/\"},\"author\":{\"name\":\"Daniel Westermann\",\"@id\":\"https:\/\/www.dbi-services.com\/blog\/#\/schema\/person\/8d08e9bd996a89bd75c0286cbabf3c66\"},\"headline\":\"What is more efficient: arrays or single column values?\",\"datePublished\":\"2015-06-15T10:48:16+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\/\/www.dbi-services.com\/blog\/what-is-more-efficient-arrays-or-single-column-values\/\"},\"wordCount\":132,\"commentCount\":0,\"image\":{\"@id\":\"https:\/\/www.dbi-services.com\/blog\/what-is-more-efficient-arrays-or-single-column-values\/#primaryimage\"},\"thumbnailUrl\":\"http:\/\/wwwold.dbi-services.com\/plugins\/editors\/jce\/tiny_mce\/plugins\/article\/img\/trans.gif\",\"keywords\":[\"PostgreSQL\"],\"articleSection\":[\"Database Administration & Monitoring\"],\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"CommentAction\",\"name\":\"Comment\",\"target\":[\"https:\/\/www.dbi-services.com\/blog\/what-is-more-efficient-arrays-or-single-column-values\/#respond\"]}]},{\"@type\":\"WebPage\",\"@id\":\"https:\/\/www.dbi-services.com\/blog\/what-is-more-efficient-arrays-or-single-column-values\/\",\"url\":\"https:\/\/www.dbi-services.com\/blog\/what-is-more-efficient-arrays-or-single-column-values\/\",\"name\":\"What is more efficient: arrays or single column values? 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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 &\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":"What is more efficient: arrays or single column values? - 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\/what-is-more-efficient-arrays-or-single-column-values\/","og_locale":"en_US","og_type":"article","og_title":"What is more efficient: arrays or single column values?","og_description":"In PostgreSQL ( as well as in other rdbms ) you can define columns as arrays. 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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 &\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\/5159","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=5159"}],"version-history":[{"count":0,"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/posts\/5159\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/media?parent=5159"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/categories?post=5159"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/tags?post=5159"},{"taxonomy":"type","embeddable":true,"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/type_dbi?post=5159"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}