DB2 中varchar 与 char在使用时有什么性能差？

some simple test :)

$ vim test.sh
"test.sh" 36 lines, 1039 characters
    +1  #!/bin/ksh
    +2  integer i=0
    +3  db2 connect to sample > /dev/null
    +4  db2 drop table t3 > /dev/null
    +5  db2 drop table t4 > /dev/null
    +6  db2 "create table t3 (c1 char(5))" > /dev/null
    +7  db2 "create table t4 (c1 varchar(5))" > /dev/null
    +8  echo "before insert to char table:"
    +9  date
   +10  while (( $i <= 100 ))
   +11  do
   +12    db2 +c "insert into t3 values ('12345')"  > /dev/null
   +13    db2 +c "insert into t3 values ('23456')"  > /dev/null
   +14    db2 +c "insert into t3 values ('34567')"  > /dev/null
   +15    db2 +c "insert into t3 values ('45678')"  > /dev/null
   +16    db2 +c "insert into t3 select * from t3" > /dev/null
   +17    db2 +c "insert into t3 select * from t3" > /dev/null
   +18    db2 +c "insert into t3 select * from t3" > /dev/null
   +19    db2 +c "insert into t3 select * from t3" > /dev/null
   +20    db2 +c "insert into t3 select * from t3" > /dev/null
   +21    db2 +c "insert into t3 select * from t3" > /dev/null
   +22    db2 +c "insert into t3 select * from t3" > /dev/null
   +23    db2 +c "insert into t3 select * from t3" > /dev/null
   +24    db2 commit  > /dev/null
   +25    db2 delete from t3  > /dev/null
   +26    i=$i+1
   +27  done
   +28  echo "after insert to char table:"
   +29  date
   +30  echo "before insert to varchar table:"
   +31  date
   +32  i=0
   +33  while (( $i <= 100 ))
   +34  do
   +35     db2 +c "insert into t4 values ('12345')"  > /dev/null
   +36     db2 +c "insert into t4 values ('23456')"  > /dev/null
   +37     db2 +c "insert into t4 values ('34567')"  > /dev/null
   +38     db2 +c "insert into t4 values ('45678')"  > /dev/null
   +39     db2 +c "insert into t4 select * from t4" > /dev/null
   +40     db2 +c "insert into t4 select * from t4" > /dev/null
   +41     db2 +c "insert into t4 select * from t4" > /dev/null
   +42     db2 +c "insert into t4 select * from t4" > /dev/null
   +43     db2 +c "insert into t4 select * from t4" > /dev/null
   +44     db2 +c "insert into t4 select * from t4" > /dev/null
   +45     db2 +c "insert into t4 select * from t4" > /dev/null
   +46     db2 +c "insert into t4 select * from t4" > /dev/null
   +47     db2 commit  > /dev/null
   +48     db2 delete from t4  > /dev/null
   +49     i=$i+1
   +50  done
   +51  echo "after insert to varchar table:"
   +52  date
"test.sh" 52 lines, 1927 characters
$ test.sh
before insert to char table:
Wed Mar 18 10:55:28 EDT 2009
after insert to char table:
Wed Mar 18 10:56:34 EDT 2009
before insert to varchar table:
Wed Mar 18 10:56:34 EDT 2009
after insert to varchar table:
Wed Mar 18 10:57:42 EDT 2009
$收起

勤劳的wangzhonnew版主，赞一个！收起

实践说明一切，谢谢专家的实验收起

CHAR性能优于VARCHAR   看你场景了~~~能用CHAR尽量就是CHAR啦~~收起

:victory:收起

确实，要根据具体业务来使用char 和varchar字段收起

char直接取。
varchar第一步判断长度，第二步取内容收起

Thanks share information收起

各有利弊！收起

:lol :lol :lol ................
学习了收起