{"id":4792,"date":"2015-05-18T15:05:22","date_gmt":"2015-05-18T13:05:22","guid":{"rendered":"https:\/\/www.dbi-services.com\/blog\/does-impdb-into-a-compressed-table-really-compress-data\/"},"modified":"2015-05-18T15:05:22","modified_gmt":"2015-05-18T13:05:22","slug":"does-impdb-into-a-compressed-table-really-compress-data","status":"publish","type":"post","link":"https:\/\/www.dbi-services.com\/blog\/does-impdb-into-a-compressed-table-really-compress-data\/","title":{"rendered":"does impdb into a compressed table really compress data?"},"content":{"rendered":"<p>Today at a customer we discussed the following scenario: To refresh a test database a datapump export and import was implemented. To save space on the test system the idea came up to compress the data on the test system. When we checked the <a href=\"http:\/\/docs.oracle.com\/database\/121\/ADMIN\/tables.htm#ADMIN13948\" target=\"_blank\" rel=\"noopener\">documentation<\/a> we came across the following statement:<\/p>\n<p>&#8220;When you use basic table compression, warehouse compression, or archive compression, compression only occurs when data is bulk loaded into a table.&#8221;<\/p>\n<p>So the question was: Is datapump loading data in bulk in the sense of the sentence above? Needs to be tested:<\/p>\n<pre class=\"brush: actionscript3; gutter: true; first-line: 1\">connect \/ as sysdba\ndrop user demo cascade;\ndrop user demo2 cascade;\ncreate or replace directory dir_tmp as '\/var\/tmp';\ncreate user demo identified by demo default tablespace users;\ncreate user demo2 identified by demo default tablespace users;\ngrant dba to demo;\ngrant dba to demo2;\ncreate table demo.DEMO (\"id\" number primary key, \"text\" varchar2(15), \"number\" number) ;\ncreate table demo2.demo compress basic as select * from demo.demo;\nset timing on\n declare\n  type people_array is varray(12) of varchar(15);\n  people people_array := people_array( 'Marc', 'Bill', 'George', 'Eliot', 'Matt', 'Trey', 'Tracy','Greg', 'Steve', 'Kristina', 'Katie', 'Jeff' );\n  people_count number :=people.COUNT;\n  type DEMO_record_type is record (\"user_id\" number , \"name\" varchar2(15), \"number\" number) ;\n  type DEMO_collection_type is table of DEMO_record_type index by binary_integer;\n  DEMO_collection DEMO_collection_type;\n begin\n  -- fill the collection\n  for i in 1..1e6 loop\n   DEMO_collection(i).\"user_id\":=i;\n   DEMO_collection(i).\"name\":=people( dbms_random.value(1,people.count) );\n   DEMO_collection(i).\"number\":=trunc(dbms_random.value(0,10000));\n   null;\n  end loop;\n  forall i in 1..DEMO_collection.count insert \/*+ append_values *\/ into demo.DEMO values DEMO_collection(i);\n  commit;\n end;\n \/\nselect sum(bytes)\/1024\/1024 mb_used from dba_extents where segment_name='DEMO' and owner='DEMO';\n!rm -f \/var\/tmp\/demo.*\n!expdp userid=\"'\/ as sysdba'\" schemas=demo directory=dir_tmp dumpfile=demo.dmp logfile=demo.log\n!impdp userid=\"'\/ as sysdba'\" directory=dir_tmp dumpfile=demo.dmp logfile=demo.log remap_schema=demo:demo2 TABLE_EXISTS_ACTION=APPEND\nselect sum(bytes)\/1024\/1024 mb_used from dba_extents where segment_name='DEMO' and owner='DEMO2';\n<\/pre>\n<p>The important output of the script for the uncompressed table is:<\/p>\n<pre class=\"brush: actionscript3; gutter: true; first-line: 1\">MB_USED\n ----------\n 22<\/pre>\n<p>.. and for the compressed table:<\/p>\n<pre class=\"brush: actionscript3; gutter: true; first-line: 1\">MB_USED\n ----------\n 16\n So, the answer is: Yes.<\/pre>\n<p>Btw: In 12c there is a <a href=\"http:\/\/docs.oracle.com\/database\/121\/SUTIL\/dp_import.htm\" target=\"_blank\" rel=\"noopener\">transform switch<\/a> to enable table compression without pre-creating the table:<\/p>\n<pre class=\"brush: actionscript3; gutter: true; first-line: 1\">impdp userid=\"'\/ as sysdba'\" directory=dir_tmp dumpfile=demo.dmp logfile=demo.log remap_schema=demo:demo2 TRANSFORM=TABLE_COMPRESSION_CLAUSE:COMPRESS<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>Today at a customer we discussed the following scenario: To refresh a test database a datapump export and import was implemented. To save space on the test system the idea came up to compress the data on the test system. When we checked the documentation we came across the following statement: &#8220;When you use basic [&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":[198],"tags":[240,246,96],"type_dbi":[],"class_list":["post-4792","post","type-post","status-publish","format-standard","hentry","category-database-management","tag-data-pump","tag-dbms-compression","tag-oracle"],"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>does impdb into a compressed table really compress data? - 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\/does-impdb-into-a-compressed-table-really-compress-data\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"does impdb into a compressed table really compress data?\" \/>\n<meta property=\"og:description\" content=\"Today at a customer we discussed the following scenario: To refresh a test database a datapump export and import was implemented. To save space on the test system the idea came up to compress the data on the test system. When we checked the documentation we came across the following statement: &#8220;When you use basic [&hellip;]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.dbi-services.com\/blog\/does-impdb-into-a-compressed-table-really-compress-data\/\" \/>\n<meta property=\"og:site_name\" content=\"dbi Blog\" \/>\n<meta property=\"article:published_time\" content=\"2015-05-18T13:05:22+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\/does-impdb-into-a-compressed-table-really-compress-data\/#article\",\"isPartOf\":{\"@id\":\"https:\/\/www.dbi-services.com\/blog\/does-impdb-into-a-compressed-table-really-compress-data\/\"},\"author\":{\"name\":\"Daniel Westermann\",\"@id\":\"https:\/\/www.dbi-services.com\/blog\/#\/schema\/person\/8d08e9bd996a89bd75c0286cbabf3c66\"},\"headline\":\"does impdb into a compressed table really compress data?\",\"datePublished\":\"2015-05-18T13:05:22+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\/\/www.dbi-services.com\/blog\/does-impdb-into-a-compressed-table-really-compress-data\/\"},\"wordCount\":135,\"commentCount\":0,\"keywords\":[\"Data pump\",\"DBMS compression\",\"Oracle\"],\"articleSection\":[\"Database management\"],\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"CommentAction\",\"name\":\"Comment\",\"target\":[\"https:\/\/www.dbi-services.com\/blog\/does-impdb-into-a-compressed-table-really-compress-data\/#respond\"]}]},{\"@type\":\"WebPage\",\"@id\":\"https:\/\/www.dbi-services.com\/blog\/does-impdb-into-a-compressed-table-really-compress-data\/\",\"url\":\"https:\/\/www.dbi-services.com\/blog\/does-impdb-into-a-compressed-table-really-compress-data\/\",\"name\":\"does impdb into a compressed table really compress data? - dbi Blog\",\"isPartOf\":{\"@id\":\"https:\/\/www.dbi-services.com\/blog\/#website\"},\"datePublished\":\"2015-05-18T13:05:22+00:00\",\"author\":{\"@id\":\"https:\/\/www.dbi-services.com\/blog\/#\/schema\/person\/8d08e9bd996a89bd75c0286cbabf3c66\"},\"breadcrumb\":{\"@id\":\"https:\/\/www.dbi-services.com\/blog\/does-impdb-into-a-compressed-table-really-compress-data\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/www.dbi-services.com\/blog\/does-impdb-into-a-compressed-table-really-compress-data\/\"]}]},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/www.dbi-services.com\/blog\/does-impdb-into-a-compressed-table-really-compress-data\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Accueil\",\"item\":\"https:\/\/www.dbi-services.com\/blog\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"does impdb into a compressed table really compress data?\"}]},{\"@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":"does impdb into a compressed table really compress data? - 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\/does-impdb-into-a-compressed-table-really-compress-data\/","og_locale":"en_US","og_type":"article","og_title":"does impdb into a compressed table really compress data?","og_description":"Today at a customer we discussed the following scenario: To refresh a test database a datapump export and import was implemented. 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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). 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