\u884c\u7684\u94fe\u63a5:\u662f\u8868\u7ed3\u6784\u8bbe\u8ba1\u95ee\u9898(\u8868\u592a\u5bbd)\uff01\u4e0d\u53ef\u6d88\u9664\uff01\u5c06\u8868\u5782\u76f4\u5206\u5272\uff01<\/p>\n
\u884c\u7684\u8fc1\u79fb:insert<\/p>\n
char(20) –><\/p>\n
drop table t purge;
\ncreate table t (x varchar2(20));<\/p>\n
begin
\nfor i in 1..1000 loop
\ninsert into t values (‘A’);
\nend loop;
\ncommit;
\nend;
\n\/<\/p>\n
\u6536\u96c6\u5bf9\u8c61\u7684\u7edf\u8ba1\u4fe1\u606f:
\nanalyze table t compute statistics;<\/p>\n
\u67e5\u770b\u7edf\u8ba1\u4fe1\u606f:
\nselect TABLE_NAME,BLOCKS,EMPTY_BLOCKS,NUM_ROWS,AVG_ROW_LEN,CHAIN_CNT
\nfrom user_tables where table_name=’T’;<\/p>\n
TABLE_NAME BLOCKS EMPTY_BLOCKS NUM_ROWS AVG_ROW_LEN CHAIN_CNT
\n———- ———- ———— ———- ———– ———-
\nT 5 3 1000 5 0 –\u6ca1\u6709\u8fc1\u79fb<\/p>\n
\u66f4\u65b0\u8868\u4ea7\u751f\u8fc1\u79fb:
\nupdate t set x=’AAAAAAAAAAAAAAAAAAAA’;
\ncommit;<\/p>\n
\u91cd\u65b0\u6536\u96c6\u5bf9\u8c61\u7684\u7edf\u8ba1\u4fe1\u606f:
\nanalyze table t compute statistics;<\/p>\n
select TABLE_NAME,BLOCKS,EMPTY_BLOCKS,NUM_ROWS,AVG_ROW_LEN,CHAIN_CNT from user_tables where table_name=’T’;<\/p>\n
TABLE_NAME BLOCKS EMPTY_BLOCKS NUM_ROWS AVG_ROW_LEN CHAIN_CNT
\n———- ———- ———— ———- ———– ———-
\nT 13 3 1000 28 659–\u4ea7\u751f\u8fc1\u79fb<\/p>\n
\u6d88\u9664\u8fc1\u79fb:
\n1.exp –> drop –> imp
\n2.alter table t move; –>\u7d22\u5f15\u5168\u5931\u6548–>alter index xxxx rebuild;
\n3.\u627e\u5230\u8fc1\u79fb\u7684\u884c\u5bfc\u51fa\uff0c\u5220\u9664\uff0c\u5bfc\u5165
\n@?\/rdbms\/admin\/utlchain –>create table chained_rows ();<\/p>\n
\u4f7f\u7528\u5206\u6790\u547d\u4ee4\u5c06\u4ea7\u751f\u8fc1\u79fb\u7684\u884c\u7684rowid\u63d2\u5165\u5230chained_rows\u8868:
\nanalyze table t list chained rows into chained_rows;<\/p>\n
create table tmp as select * from t where rowid in (select head_rowid from chained_rows);
\ndelete t where rowid in (select head_rowid from chained_rows);
\ninsert into t select * from tmp;
\ndrop table tmp purge;
\nanalyze table t compute statistics;
\nselect TABLE_NAME,BLOCKS,EMPTY_BLOCKS,NUM_ROWS,AVG_ROW_LEN,CHAIN_CNT
\nfrom user_tables where table_name=’T’;<\/p>\n","protected":false},"excerpt":{"rendered":"
\u884c\u7684\u94fe\u63a5:\u662f\u8868\u7ed3\u6784\u8bbe\u8ba1\u95ee\u9898(\u8868\u592a\u5bbd)\uff01\u4e0d\u53ef\u6d88\u9664\uff01\u5c06\u8868\u5782\u76f4\u5206\u5272 …<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"enabled":false},"version":2}},"categories":[6],"tags":[],"class_list":["post-13","post","type-post","status-publish","format-standard","hentry","category-6"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p7zRbQ-d","_links":{"self":[{"href":"https:\/\/www.lisq.net\/index.php?rest_route=\/wp\/v2\/posts\/13","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.lisq.net\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.lisq.net\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.lisq.net\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.lisq.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=13"}],"version-history":[{"count":1,"href":"https:\/\/www.lisq.net\/index.php?rest_route=\/wp\/v2\/posts\/13\/revisions"}],"predecessor-version":[{"id":14,"href":"https:\/\/www.lisq.net\/index.php?rest_route=\/wp\/v2\/posts\/13\/revisions\/14"}],"wp:attachment":[{"href":"https:\/\/www.lisq.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=13"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.lisq.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=13"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.lisq.net\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=13"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}