Oracle Linux 操作系統及數據庫的時區機制分析

1. /etc/localtime

這個文件記錄的是系統的時區，缺省的數據庫由此獲得時區信息

這個文件是二進制文件，修改該文件的方法是拷貝/usr/share/zoneinfo下的相應時區文件覆蓋 localtime 文件。

/etc/sysconfig/clock 與 localtime 配置，定義的是時區名稱區域信息等。

2./usr/share/zoneinfo/

該目錄存儲所有合法的時區信息,如果會話設置的時區和系統時區不一致，則由此讀取時區信息。

3.$ORACLE_HOME/oracore/zoneinfo

這里存儲的文件記錄數據庫的合法時區，和操作系統提供的信息會進行對比。

-rw-rw-r--. 1 oracle oinstall?? 1407 Jun? 1? 2009 readme.txt

-rw-rw-r--. 1 oracle oinstall 408315 Apr 14? 2010 timezlrg.dat

-rw-rw-r--. 1 oracle oinstall 160733 Apr 14? 2010 timezone.dat4.Linux上的時區信息可以通過 tzselect 命令查看，使用 timeconfig 進行配置修改

5.會話級別的時區設置可以如下進行

TZ='Asia/Shanghai';export TZ

6.hwclock -w

保存時區設置使之重啟系統后仍生效

關于Oracle的時區選項與時區關系，可以通過strace跟蹤進程，清晰的獲得整個流程：

分析整個過程中的文件讀取：

open("/etc/ld.so.preload", O_RDONLY)??? = 3

open("/u01/app/oracle/product/10.2.0/db_1/lib/tls/x86_64/libsqlplus.so", O_RDONLY) = -1 ENOENT (No such file or directory)

open("/u01/app/oracle/product/10.2.0/db_1/lib/tls/libsqlplus.so", O_RDONLY) = -1 ENOENT (No such file or directory)

open("/u01/app/oracle/product/10.2.0/db_1/lib/x86_64/libsqlplus.so", O_RDONLY) = -1 ENOENT (No such file or directory)

open("/u01/app/oracle/product/10.2.0/db_1/lib/libsqlplus.so", O_RDONLY) = 3

open("/u01/app/oracle/product/10.2.0/db_1/lib/libclntsh.so.10.1", O_RDONLY) = 3

open("/u01/app/oracle/product/10.2.0/db_1/lib/libnnz10.so", O_RDONLY) = 3

open("/u01/app/oracle/product/10.2.0/db_1/lib/libdl.so.2", O_RDONLY) = -1 ENOENT (No such file or directory)

open("/etc/ld.so.cache", O_RDONLY)????? = 3

open("/lib64/libdl.so.2", O_RDONLY)???? = 3

open("/u01/app/oracle/product/10.2.0/db_1/lib/libm.so.6", O_RDONLY) = -1 ENOENT (No such file or directory)

open("/lib64/libm.so.6", O_RDONLY)????? = 3

open("/u01/app/oracle/product/10.2.0/db_1/lib/libpthread.so.0", O_RDONLY) = -1 ENOENT (No such file or directory)

open("/lib64/libpthread.so.0", O_RDONLY) = 3

open("/u01/app/oracle/product/10.2.0/db_1/lib/libnsl.so.1", O_RDONLY) = -1 ENOENT (No such file or directory)

open("/lib64/libnsl.so.1", O_RDONLY)??? = 3

open("/u01/app/oracle/product/10.2.0/db_1/lib/libc.so.6", O_RDONLY) = -1 ENOENT (No such file or directory)

open("/lib64/libc.so.6", O_RDONLY)????? = 3

open("/u01/app/oracle/product/10.2.0/db_1/lib/libsqlplusic.so", O_RDONLY) = -1 ENOENT (No such file or directory)

open("/u01/app/oracle/product/10.2.0/db_1/lib/libociicus.so", O_RDONLY) = -1 ENOENT (No such file or directory)

open("/u01/app/oracle/product/10.2.0/db_1/lib/libociei.so", O_RDONLY) = -1 ENOENT (No such file or directory)

open("/u01/app/oracle/product/10.2.0/db_1/nls/data/lx1boot.nlb", O_RDONLY) = 3

open("/u01/app/oracle/product/10.2.0/db_1/nls/data/lx00001.nlb", O_RDONLY) = 3

open("/u01/app/oracle/product/10.2.0/db_1/nls/data/lx20354.nlb", O_RDONLY) = 3

open("/u01/app/oracle/product/10.2.0/db_1/nls/data/lx10001.nlb", O_RDONLY) = 3

open("/u01/app/oracle/product/10.2.0/db_1/nls/data/lx40011.nlb", O_RDONLY) = 3

open("/u01/app/oracle/product/10.2.0/db_1/nls/data/lx20001.nlb", O_RDONLY) = 3

open("/u01/app/oracle/product/10.2.0/db_1/nls/data/lx40001.nlb", O_RDONLY) = 3

open("/u01/app/oracle/product/10.2.0/db_1/sqlplus/mesg/sp1us.msb", O_RDONLY) = 3

open("/u01/app/oracle/product/10.2.0/db_1/sqlplus/mesg/sp2us.msb", O_RDONLY) = 4

open("/u01/app/oracle/product/10.2.0/db_1/sqlplus/mesg/cpyus.msb", O_RDONLY) = 5

open("/usr/share/zoneinfo/Asia/Shanghai", O_RDONLY) = 6

open("/u01/app/oracle/product/10.2.0/db_1/oracore/zoneinfo/timezlrg.dat", O_RDONLY) = 6

open("/u01/app/oracle/product/10.2.0/db_1/rdbms/mesg/ocius.msb", O_RDONLY) = 6可以看到Oracle讀取的操作系統時區文件：

/usr/share/zoneinfo/Asia/Shanghai

這是跟進環境變量的設置讀取的，數據庫的時區文件則是：

/u01/app/oracle/product/10.2.0/db_1/oracore/zoneinfo/timezlrg.dat

這整個驗證過程和Oracle的字符集完全相同，很有意思。

By eygle on 2012-03-20 16:31 |

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