Posted by admin on 31st October 2012
最近做了一次文描系统的迁移,涉及到大量的lob表,对于这种文描表的处理,其实不建议放在oracle 的lob字段中.对于LOB相信大家肯定遇到过各种问题
LOB的直接读写往往会对存储层面造成很大的压力,瞬间的并发严重的可能导致系统的崩溃.相信维护过秒杀系统的同学深有感触。
鉴于这次的迁移.总[......]
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Tags: LOB
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Posted by admin on 20th December 2011
16号早上10点左右发现系统变慢，查看等待事件 发现大量i/o salve wait, load 比值增加，等待语句sql_id为 38wm92jbxu0vf
09:59:30 up 80 days, 8:00, 2 users, load average: 16.02, 4.67, 2.95
SID USERNAME MACHINE EVENT SQL ST LT LOGON_TIME
------ ---------- ---------------------- ------------------------------ ---------------------------- -- ------ ----------
1753 USER_DATA2 JDBC Thin Client log file sync /cqy9u8yvwhftq A 0 22175
2250 USER_DATA2 JDBC Thin Client SQL*Net more data from client /3s4uqa7n9z9hf I 0 22087
2115 USER_DATA2 JDBC Thin Client SQL*Net more data from client /3s4uqa7n9z9hf I 0 22746
2096 PROD_DATA2 JDBC Thin Client SQL*Net message from client 30hsdmcf9zyhq/34vfybbn2m7bc A 0 27989
835 USER_DATA2 JDBC Thin Client direct path read 38wm92jbxu0vf/3s4uqa7n9z9hf A 0 22194
928 USER_DATA2 JDBC Thin Client i/o slave wait 38wm92jbxu0vf/3s4uqa7n9z9hf A 0 22749
947 USER_DATA2 JDBC Thin Client SQL*Net more data to client 38wm92jbxu0vf/3s4uqa7n9z9hf A 0 22682
957 USER_DATA2 JDBC Thin Client i/o slave wait 38wm92jbxu0vf/3s4uqa7n9z9hf A 0 22754
961 USER_DATA2 JDBC Thin Client i/o slave wait 38wm92jbxu0vf/3s4uqa7n9z9hf A 0 22751
972 USER_DATA2 JDBC Thin Client SQL*Net message from client 38wm92jbxu0vf/3s4uqa7n9z9hf A 0 22172
981 USER_DATA2 JDBC Thin Client i/o slave wait 38wm92jbxu0vf/3s4uqa7n9z9hf A 0 22177
985 USER_DATA2 JDBC Thin Client i/o slave wait 38wm92jbxu0vf/3s4uqa7n9z9hf A 0 22174
991 USER_DATA2 JDBC Thin Client i/o slave wait 38wm92jbxu0vf/3s4uqa7n9z9hf A 0 22172
992 USER_DATA2 JDBC Thin Client i/o slave wait 38wm92jbxu0vf/3s4uqa7n9z9hf A 0 22176
994 USER_DATA2 JDBC Thin Client i/o slave wait
OSW报告显示系统在9:58-10:00之间经历了大量的io wait，从下面的数[......]
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Tags: LOB
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