UKoom » Database

Register table issue caused by using wrong column type in SQL

ukoom — Tue, 07 Dec 2010 03:54:26 +0000

Wow, how long the title is!

I came across one strange issue today (actually I found this last Friday, but you know weekend coming, hehehe).

When using the update DQL to fill up one new column in the registered table, there are always lots of blanks appended.

The root cause after doing some investigation, what I found:

We are adding the column in type – char rather than varchar2 which is the normal one.

CHAR should be used for storing fix length character strings. String values will be space/blank padded before stored on disk.

Baiqing, one of my colleges , wrote the DQL to add the new column. I believe that:

1. He should be more careful

2. The DQL used to register table in Documentum are defining the type as ‘char’. Documentum is using ‘char’ type to define variable length character strings. there is no type to define fix length strings. That make developer confused.

Anyway, the cause was found. Happy Monday!!!!

Reference:

http://www.orafaq.com/faq/what_is_the_difference_between_varchar_varchar2_and_char_data_types

SQL Server Profiler – Only TrueType fonts are supported

ukoom — Sun, 22 Aug 2010 05:12:27 +0000

Error message – “Only TrueType fonts are supported. This is not a TrueType font.” was thrown when using SQL Server Profiler.

Solution：

1. Open SQL Server Profilr

2. Go to ‘ Tool’Menu

3. Select Options

4. Change the font name to “Arial”

5. Click OK.

Get definition for view in Oracle

ukoom — Fri, 23 Apr 2010 01:19:36 +0000

set LONG 10000
select TEXT from ALL_VIEWS where view_name = ‘MY_VIEW‘;

Line one must be at least the size of the statement used to create the view. Either pick a really big number if you think the view is large or use the following to determine how long it is first. If it isn’t, the text will be truncated

select text_length from all_views where view_name = ‘MY_VIEW’

NOTE: name of the view is case sensitive as are most every thing in Oracle.

If you want to capture output to something other than a SQL Plus window such as a file, be sure to include do the following before you execute the select statement.

spool c:\v_person.sql

To close the file when you are done writing output to it, call the following:

spool off

To summarize:

select text_length from all_views where view_name = ‘MY_VIEW’

10000

– whatever value you get back, use on the next statement.

set LONG 10000

spool c:\v_person.sql

select TEXT from ALL_VIEWS where view_name = ‘MY_VIEW‘;

spool off

PowerDesigner Non SQLError

ukoom — Fri, 05 Feb 2010 05:35:56 +0000

The error “Non SQLError Could not load class Driver_name” was thrown when using PowerDesigner to generate the hibernate mapping files.

This error occurs if you enter an incorrect Driver and URL in the Database Profile.

PowerDesigner Reverse Engineer

ukoom — Fri, 05 Feb 2010 05:34:06 +0000

Get the Physical Data Model
1. Menu Operation
File, Reverse Engineer , Database, New Phycial Data Model
2. Connection
Add a connect to the target database
3. Choose tables to generate the models

Generate the Java Code
1. Menu Operation
Tools , Generate Object-Oriented Model, Detail, O/R Mapping,
Enable Transformations, Extended Model Definitions, O/R Mapping, Hibernate

To be continued.

Import MySQL dumpfile

ukoom — Wed, 27 Jan 2010 05:55:32 +0000

how to correctly import a MySQL dumpfile through a command line.

mysql -p -h DBSERVER dbname < dbname.sql

DateDiff 用法

ukoom — Wed, 13 Jan 2010 08:17:04 +0000

DateDiff 用法
DateDiff: SQL server函数

返回 Variant (Long) 的值，表示两个指定日期间的时间间隔数目。

语法

DateDiff(interval, date1, date2[, firstdayofweek[, firstweekofyear]])

DateDiff 函数语法中有下列命名参数：

部分描述

interval 必要。字符串表达式，表示用来计算date1 和 date2 的时间差的时间间隔

Date1□date2 必要；Variant (Date)。计算中要用到的两个日期。

Firstdayofweek 可选。指定一个星期的第一天的常数。如果未予指定，则以星期日为第一天。

firstweekofyear 可选。指定一年的第一周的常数。如果未予指定，则以包含 1 月 1 日的星期为第一周。

设置

interval 参数的设定值如下：

设置描述

yyyy 年

q 季

m 月

y 一年的日数

d 日

w 一周的日数

ww 周

hh 时

n 分钟

s 秒

firstdayofweek 参数的设定值如下：

常数值描述

vbUseSystem 0 使用 NLS API 设置。

vbSunday 1 星期日（缺省值）

vbMonday 2 星期一

vbTuesday 3 星期二

vbWednesday 4 星期三

vbThursday 5 星期四

vbFriday 6 星期五

vbSaturday 7 星期六

常数值描述

vbUseSystem 0 用 NLS API 设置。

vbFirstJan1 1 从包含 1 月 1 日的星期开始（缺省值）。

vbFirstFourDays 2 从第一个其大半个星期在新的一年的一周开始。

vbFirstFullWeek 3 从第一个无跨年度的星期开始。

说明

DateDiff 函数可用来决定两个日期之间所指定的时间间隔数目。例如，可以使用 DateDiff 来计算两个日期之间相隔几日，或计算从今天起到年底还有多少个星期。

为了计算 date1 与 date2 相差的日数，可以使用“一年的日数”(y) 或“日”(d)。当 interval 是“一周的日数”(w) 时，DateDiff 返回两日期间的周数。如果 date1 是星期一，DateDiff 计算到 date2 为止的星期一的个数。这个数包含 date2 但不包含 date1。不过，如果 interval 是“周”(ww)，则 DateDiff 函数返回两日期间的“日历周”数。由计算 date1 与 date2 之间星期日的个数而得。如果 date2 刚好是星期日，则 date2 也会被加进 DateDiff 的计数结果中；但不论 date1 是否为星期日，都不将它算进去。

如果 date1 比 date2 来得晚，则 DateDiff 函数的返回值为负数。date2-data10

firstdayofweek 参数会影响使用时间间隔符号 “W” 或 “WW” 计算的结果。

如果 date1 或 date2 是日期文字，则指定的年份成为该日期的固定部分。但是，如果 date1 或 date2 用双引号 (” “) 括起来，且年份略而不提，则在每次计算表达式 date1 或 date2 时，当前年份都会插入到代码之中。这样就可以书写适用于不同年份的程序代码。

在计算 12 月 31 日和来年的 1 月 1 日的年份差时，DateDiff 返回 1 表示相差一个年份，虽然实际上只相差一天而已。

示例

此示例确定在 pubs 数据库中标题发布日期和当前日期间的天数。

USE pubsGOSELECT DATEDIFF(day, pubdate, getdate()) AS no_of_daysFROM titlesGO

DATEDIFF函数在Access和MSSQL中的使用区别

ACCESS中用法：DATEDIFF(‘day’, pubdate, Now())

MSSQL中用法：DATEDIFF(day, pubdate, getdate())

SQL Server JDBC Connection Errors: Error establishing socket, connection refused…

ukoom — Wed, 06 Jan 2010 12:29:27 +0000

SQL Server JDBC Connection Errors: Error establishing socket, connection refused…
java.sql.SQLException: [Microsoft][SQLServer 2000 Driver for JDBC]Error establishing socket.
at com.microsoft.jdbc.base.BaseExceptions.createException(Unknown Source)
at com.microsoft.jdbc.base.BaseExceptions.getException(Unknown Source)
at com.microsoft.jdbc.base.BaseExceptions.getException(Unknown Source)
at com.microsoft.jdbc.sqlserver.tds.TDSConnection.(Unknown Source)
at com.microsoft.jdbc.sqlserver.SQLServerImplConnection.open(Unknown Source)
at com.microsoft.jdbc.base.BaseConnection.getNewImplConnection(Unknown Source)
at com.microsoft.jdbc.base.BaseConnection.open(Unknown Source)
at com.microsoft.jdbc.base.BaseDriver.connect(Unknown Source)

SQL server 2005 JDBC Driver:
com.microsoft.sqlserver.jdbc.SQLServerException: The TCP/IP connection to the host has failed.
java.net.ConnectionException: Connection refused: connect
at com.microsoft.sqlserver.jdbc.SQLServerException.makeFromDriverError(Unknown Source)
at com.microsoft.sqlserver.jdbc.SQLServerException.connect(Unknown Source)
at com.microsoft.sqlserver.jdbc.SQLServerDriver.connect(Unknown Source)

For this kind of database connection problem, there are always two distinct issues:
The SQL server itself is not running or TCP/IP is disabled. That can be confirmed by run
netstat

and see it is listed there. And then run

telnet localhost 1433

and see it can connect (or whatever port number).

Even if the server is running, a client program such like jdbc may still fail to connect to it because of a
firewall

For testing, you can turn off the XP firewall. And if you have other firewall running, check the firewall log and see any activities that might be related.

You can also verify whether or not your server is running from the

SQL Server Network Utility
on the server, or from another client utility such as

SQL Query Analyzer

or a command line utility such as

osql

To check the enabled protocols for a server, follow these steps:
In SQL Server 2000, start the SQL Server Network Utility (svrnetcn.exe).
On the General tab, select the instance of Microsoft SQL Server on which to load an installed server network library.
Make sure that TCP/IP appears in the Enabled Protocols list.
To find the port number, in the Enabled Protocols list, click TCP/IP, and then click Properties. The Properties dialog box displays the port number.
There is an known bug: SQL Server May Not Listen on TCP/IP Sockets When TCP/IP is the Only Protocol
In a SQL Server 2000 custom installation, if TCP/IP is the only selected protocol and all other protocols are disabled, SQL Server may not initialize and listen on TCP/IP sockets. The Server Network Utility shows that it is listening only on TCP/IP port 1433 even though it is not. To identify if SQL Server is not listening on TCP/IP, check to see if the value for TcpPort in the following registry key is incorrectly set to blank or empty:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server\ [Instance Name]\MSSQLServer\SuperSocketNetLib\Tcp\REG_SZ TcpPort=

To work around this problem, follow these steps:

Start Registry Editor (Regedt32.exe).
Locate the TcpPort value in the following key in the registry:
Named instance:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server\[InstanceName]\MSSQLServer\SuperSocketNetLib\Tcp\TcpPort

Default instance:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MSSQLServer
\MSSQLServer\SuperSocketNetLib\TCP\TcpPort

. On the Edit menu, click String. Enter either of the following values:
a. Type the port number you want. -or-
b. Enter a value of 0 to have SQL Server dynamically detect and assign a port the next time SQL Server starts.

Click OK.
Quit Registry Editor.
SQL Server 2000 Service Pack 4 (SP4):

You are running a version of Microsoft SQL Server 2000 or Microsoft SQL Server 2000 Desktop Engine (also called MSDE) that has known security vulnerabilities when used in conjunction with the Microsoft Windows Server 2003 family. To reduce your computer’s vulnerability to certain virus attacks, the TCP/IP and UDP network ports of Microsoft SQL Server 2000, MSDE, or both have been disabled. To enable these ports, you must install SQL Server 2000 Service Pack 3a, or the most recent service pack for Microsoft SQL Server 2000 or MSDE from http://www.microsoft.com/sql/downloads/2000/sp4.mspx.

Oracle Tuning Documentum Server

ukoom — Mon, 07 Dec 2009 06:44:56 +0000

Modifying the dmcl.ini File on the Oracle WebCenter Content Service for Documentum Host

On all computers that host the Oracle WebCenter Content Service for Documentum, you can increase the max_session_count variable in the dmcl.ini file to allow for additional concurrent sessions. By default, the max_session_count is set to 10, meaning there can be 10 concurrent sessions to Documentum.

The number of Documentum sessions depends on the number of content crawlers you expect to run concurrently, as well as the number of users you expect to click through links concurrently. We recommend you set the max_session_count parameter accordingly. You can increase this setting later if you find that you run out of sessions or want to increase the number of content crawlers running simultaneously.
A session is started for each user with a unique user name/password that tries to click through to a Documentum document in the portal. The max_session_count must accommodate the estimated number of click through users to be handled concurrently.

Modifying the server.ini File on the Documentum Server

On the Documentum Server computer, you can change the settings in the server.ini file to allow for additional concurrent sessions.

The concurrent_sessions variable controls the number of connections the Documentum server can handle concurrently. This parameter should accommodate for the sum of all the max_session_count values in your environment.

If you plan to use the Oracle WebCenter Content Service for Documentum with several different docbases, you must modify the server.ini for each docbase. When making these configuration changes, consider the following:

As with any configuration changes, take into account any hardware limitations.
The configuration settings depend on both existing and projected Documentum usage.

Oracle Session Statistics

ukoom — Mon, 07 Dec 2009 05:55:32 +0000

Here are some scripts related to Session Statistics .

Session I/O By User

SESSION I/O BY USER NOTES:

Username – Name of the Oracle process user

OS User – Name of the operating system user

PID – Process ID of the session

SID – Session ID of the session

Serial# – Serial# of the session

Physical Reads – Physical reads for the session

Block Gets – Block gets for the session

Consistent Gets – Consistent gets for the session

Block Changes – Block changes for the session

Consistent Changes – Consistent changes for the session

select	nvl(ses.USERNAME,'ORACLE PROC') username,
	OSUSER os_user,
	PROCESS pid,
	ses.SID sid,
	SERIAL#,
	PHYSICAL_READS,
	BLOCK_GETS,
	CONSISTENT_GETS,
	BLOCK_CHANGES,
	CONSISTENT_CHANGES
from	v$session ses,
	v$sess_io sio
where 	ses.SID = sio.SID
order 	by PHYSICAL_READS, ses.USERNAME

CPU Usage By Session

CPU USAGE BY SESSION NOTES:

Username – Name of the user

SID – Session id

CPU Usage – CPU centiseconds used by this session (divide by 100 to get real CPU seconds)

select 	nvl(ss.USERNAME,'ORACLE PROC') username,
	se.SID,
	VALUE cpu_usage
from 	v$session ss,
	v$sesstat se,
	v$statname sn
where  	se.STATISTIC# = sn.STATISTIC#
and  	NAME like '%CPU used by this session%'
and  	se.SID = ss.SID
order  	by VALUE desc

Resource Usage By User

RESOURCE USAGE BY USER NOTES:

SID – Session ID

Username – Name of the user

Statistic – Name of the statistic

Value – Current value

select 	ses.SID,
	nvl(ses.USERNAME,'ORACLE PROC') username,
	sn.NAME statistic,
	sest.VALUE
from 	v$session ses,
	v$statname sn,
	v$sesstat sest
where 	ses.SID = sest.SID
and 	sn.STATISTIC# = sest.STATISTIC#
and 	sest.VALUE is not null
and 	sest.VALUE != 0
order 	by ses.USERNAME, ses.SID, sn.NAME

Session Stats By Session

SESSION STAT NOTES:

Username – Name of the user

SID – Session ID

Statistic – Name of the statistic

Usage – Usage according to Oracle

select  nvl(ss.USERNAME,'ORACLE PROC') username,
	se.SID,
	sn.NAME stastic,
	VALUE usage
from 	v$session ss,
	v$sesstat se,
	v$statname sn
where  	se.STATISTIC# = sn.STATISTIC#
and  	se.SID = ss.SID
and	se.VALUE > 0
order  	by sn.NAME, se.SID, se.VALUE desc

Cursor Usage By Session

CURSOR USAGE BY SESSION NOTES:

Username – Name of the user

Recursive Calls – Total number of recursive calls

Opened Cursors – Total number of opened cursors

Current Cursors – Number of cursor currently in use

select 	user_process username,
	"Recursive Calls",
	"Opened Cursors",
	"Current Cursors"
from  (
	select 	nvl(ss.USERNAME,'ORACLE PROC')||'('||se.sid||') ' user_process,
			sum(decode(NAME,'recursive calls',value)) "Recursive Calls",
			sum(decode(NAME,'opened cursors cumulative',value)) "Opened Cursors",
			sum(decode(NAME,'opened cursors current',value)) "Current Cursors"
	from 	v$session ss,
		v$sesstat se,
		v$statname sn
	where 	se.STATISTIC# = sn.STATISTIC#
	and 	(NAME  like '%opened cursors current%'
	or 	 NAME  like '%recursive calls%'
	or 	 NAME  like '%opened cursors cumulative%')
	and 	se.SID = ss.SID
	and 	ss.USERNAME is not null
	group 	by nvl(ss.USERNAME,'ORACLE PROC')||'('||se.SID||') '
)
orasnap_user_cursors
order 	by USER_PROCESS,"Recursive Calls"

User Hit Ratios

USER HIT RATIO NOTES:

Username – Name of the user

Consistent Gets – The number of accesses made to the block buffer to retrieve data in a consistent mode.

DB Blk Gets – The number of blocks accessed via single block gets (i.e. not through the consistent get mechanism).

Physical Reads – The cumulative number of blocks read from disk.

Logical reads are the sum of consistent gets and db block gets.

The db block gets statistic value is incremented when a block is read for update and when segment header blocks are accessed.

Hit ratio should be > 90%

select	USERNAME,
	CONSISTENT_GETS,
        BLOCK_GETS,
        PHYSICAL_READS,
        ((CONSISTENT_GETS+BLOCK_GETS-PHYSICAL_READS) / (CONSISTENT_GETS+BLOCK_GETS)) Ratio
from 	v$session, v$sess_io
where 	v$session.SID = v$sess_io.SID
and 	(CONSISTENT_GETS+BLOCK_GETS) > 0
and 	USERNAME is not null
order	by ((CONSISTENT_GETS+BLOCK_GETS-PHYSICAL_READS) / (CONSISTENT_GETS+BLOCK_GETS))