Performance Of CHAR Versus VARCHAR2 In VLDB DW
Jul 20, 2010
With a very large database (VLDB) for a data warehouse (DW) using primarily a STAR based schema in an environment in which time (both human and CPU) is orders of magnitude more valuable than storage capacity, is there any signficant difference in query performance when tables have all fixed length (CHAR) columns compared to tables with variable length (VARCHAR2) columns?
I realize this is one of those "in general" questions so considering "a given VLDB DW environment" with all other things being equal, what, if any, is the time based performance difference between a database of tables with all fixed sized columns versus one of tables with variable length columns ?
View 2 Replies
ADVERTISEMENT
Dec 9, 2008
Environment Setup
Oracle Server 11g on HP-UX
Oracle Client on Windows
I am using swingbench tool to generate load on DB and using OLTP like benchmark i am comparing the performance of plain data and encrypted data.
I have created two different database. one for tde and other for plain. I have populated same number of rows in both databases. Then i start running the benchmark and i use SAR to collect disk I/O's, VSAR to CPU usage.
From the sar report it seems that,
Oracle plain has faster transactions, it uses minimum CPU. But when look in tot the Reads/Writes TDE has lower than the plain.
If TDE needs to encrypt the data to store in the disks it should occupy more space than the plain data. Then the I/O should be more in TDE..
Note: Bcz the DB parameters are same, number of rows in the tables are same. File system and its block size are same. I will run the swingbench seperately for both the databases.
I am attaching the excel sheet for sar results. Let me know if you need more information
View 7 Replies
View Related
Sep 7, 2011
I am using ORacle 10g R2.
SELECT key_value
FROM PARAMETERS
WHERE company_id = '01'
AND key_code = 'SHRINK'
AND key_desc <= 3888
AND key1 > 3888
Data type of Key_Desc and Key1 is CHAR.
The above query used to run in 9.2.0.5 and now in 10.2.0.4 i am getting invalid identified error..
View 16 Replies
View Related
Nov 10, 2010
I did a search on this topic and did see the ASK TOM response that storing all varchar2 fields as (2000) or what not is a bad idea based on an array fetch that developers may use etc. However I'm not sure that applies to my specific question, and the other examples he gave certainly didn't apply. So I'll pose the question a different way:
Question #1: Is there, for example, a performance difference between setting a field as varchar(2000) and varchar(25) if I was just running a native SQL query using a front end tool like TOAD?
Question #2: If I also need to index that field, will it take longer to index a varchar(2000) field than a varchar(25) field, assuming the same data is in both fields?
View 2 Replies
View Related
Jan 27, 2011
I was comparing cost of rebuild vs create index...I carried out the following test
SQL> create table t4 as select * from t1;
Table created.
SQL> create table t5 as select * from t1 where 1=2;
Table created.
SQL> create index i5 on t5(id);
Index created. SQL> select bytes,extents,blocks from user_segments where segment_name='I5';
BYTES EXTENTS BLOCKS
---------- ---------- ----------
65536 1 8
SQL> alter index i5 unusable;
Index altered.
SQL> alter table t5 nologging;
Table altered.
SQL> Alter session set skip_unusable_indexes=True;
Session altered.
SQL> insert /*+ append */ into t5 select * from t1;
563904 rows created.
SQL> commit;
Commit complete.
Now I compared the cost (elapsed time, logical I/O) of the operations
create index i4 on t4(id);
Vs
alter index i5 rebuild online;
Following is the related trace of above 2 steps
create index i4 on t4(id)
call count cpu elapsed disk query current rows
------- ------ -------- ---------- ---------- ---------- ---------- ----------
Parse 1 0.00 0.00 0 1 0 0
Execute 1 1.17 3.38 9497 7869 335 0
Fetch 0 0.00 0.00 0 0 0 0
------- ------ -------- ---------- ---------- ---------- ---------- ----------
total 2 1.17 3.38 9497 7870 335 0
Misses in library cache during parse: 1
Optimizer goal: CHOOSE
Parsing user id: 5
[code]....
So which option we shall pick in such cases? {Of course I haven't set 'nologging' for the indices but it is same for both indices we are comparing}
View 2 Replies
View Related
May 7, 2011
I am currently in the favorable situation in which I have excess amounts of memory available on the database server - a single node setup. The server only serves the single instance and no other processing. Database size is around 2.3tb and memory is 50gb. For the majority of processing, AIX is allocating a significant amount (anywhere from 30-40%) of the memory to the AIX file system cache (persistent pages).
I've been trying to find documentation about this, but have not had any luck yet. My guess is that it would be better to allow Oracle to cache this data - meaning increase the SGA target and max size to allow for a larger buffer cache. However, the nice thing about the AIX cache is if process memory is needed, the file system cache gives up pages. If the memory was allocated to the SGA, its pretty much locked in.
I have read several articles stating that a larger buffer cache is not always better, as a larger cache takes more management. But having both of the caches active seem to be a waste of memory, effectively storing the data twice - once in AIX persistent pages and a second time in Oracle database buffer cache.
View 4 Replies
View Related
Dec 9, 2011
If you have 3 tables (yr09, yr10,yr11) one with 2009 data, 2010 and 2011 data respectively. And a view (vw_yr091011) with a "union all" on all three.
Question: Will the performance be same for the following two queries ?
Question: Will Oracle read all 3 tables in the view when we search for only one year ?
select count(*) from yr09
where year = 2009;
-- vs
select count(*) from vw_yr091011
where year = 2009;
The following link says yes, the performance remains the same.
Link: [URL]..........
when I tried on a volume of 14000 records. The count came out same but the view took 50 more sec. And the explain plan shows it accessed all three tables.
View 9 Replies
View Related
Nov 6, 2012
I have been used to the consciousness that we should use the minimum length for varchar2 field that can store the data we need manipulate. But recently I was told that it has little impact on performance if we assign a much longer size.
View 13 Replies
View Related
Aug 18, 2010
How does standard vs advanced handle index compression? Is there an advantage to having one vs the other besides the incurred cost?
View 3 Replies
View Related
Oct 27, 2010
I want to pass english character as a parameter and search a string that having swedish character, this needs to be done for all the swedish characters.
test _t table having the below 3 values
päiväp
metervara
flerfärgad
1. If user searches based on english char like below then they should get all the 3 values bcz fist & last have swedish ä and second one having english a.
Query : select name from test_t where name like '%a%'
Regsult:
päiväp
metervara
fräg
2. If user searches based on swedish char like below then they should get only 2 values bcz fist & last have swedish ä and second one having english a.
select name from test_t where name like '%ä%'
päiväp
fräg
Is any in-built function available, for Text alternative string search. If not how to search the string based on the query.
View 6 Replies
View Related
Aug 15, 2011
I have two design alternatives and need to understand how expensive (speed) is one of them against the other for a medium size table (100K-200K records):
create table xyz
(
f1 number not null,
f2 varchar2(20) not null,
f3 number not null,
f4 varchar2(50),
[code]....
the idea is to optimize the design by using a PK instead of the 3 keys and there is a debate that searching a unique index field(2nd scenario) is of the same speed than searching a PK field (1st scenario).
View 5 Replies
View Related
Jul 22, 2009
I have a table with column val1 having data's starting with 0920 and 4 digit char values.
so we have the query to find
select * from table
where val1 between '0920' and 'ZZZZ'
will it work fine?
View 1 Replies
View Related
Jun 28, 2011
I have a huge table (about 60 gb) partition over range. The index on this table is global index created on 4 columns together. I have a query which is running very slowly. The explain plan is showing the use of this global index.Explain plan is not showing pstart and pend because the index is global.
View 6 Replies
View Related
Oct 24, 2007
i am fairly new in the oracle arena, but what would cause a statement such as
ALTER TABLE TEST_TABLE MODIFY text_field1 varchar2(100) DEFAULT 'testval' NULL
to change a column's type from VARCHAR2(100) to VARCHAR2(100 byte)? i found a few mentions of the 100 byte concept online but nothing that jumped out at me.
View 2 Replies
View Related
Dec 13, 2012
oracle 11 g xe
1) I want to pass date in '12 Dec 2012'(CHARECTER) while calling SP and in side SP i have declared parameter as DATE so I think it should not create any problem in any condition whether it is passed from oracle client or any other front end?
2) I have date in (date type variable) , how to convert it into char but it should be in iso format (i want iso format , so that it should not create any problem in any condition).
3) How to convert (date in char- in iso or any good format) into (date type variable) (so that it should not create problem and this is why i wanted char date in iso format).
4) If there is any good format and function to convert (date to char) and (char to date)?
View 5 Replies
View Related
Feb 11, 2009
Well the company i work for has just recently upgraded from Oracle 9i to 10g. We are having various problems with the migration, and with certain code breaking. My question regards this piece of code;
[code]
to_number(to_char('a_date','YYYY'))
[code]
There are various statements like the one above scattered throughout a query i am trying to fix. When run, the query returns an "invalid number ora-01722" error, which i know is caused by the above code.
if this method of converting from date, to character was discontinued from 9i to 10g?it just seems strange as there are a lot of statements like the one above and they must have worked at some point, but now i cant even get one to work on its own.
View 3 Replies
View Related
Feb 7, 2013
converting a string to date, my string looks like '01022013' '04022013', I tried to_date('01022013', 'dd-mm-yyyy') but couldn't work.
View 6 Replies
View Related
Mar 16, 2011
I've got a table with varchar records and I need to separate numerical value and convert into the number datatype.
create table tmp_mape
(remark varchar2(100) )
insert into tmp_mape values ('Dobitie zdarma 3,32EUR 0910105067 02/02')
insert into tmp_mape values ( 'Dobitie pravidelné 9,00EUR' )
I just need to get values 3.32 and 9 from that example into the new column.
The select below returns ORA-01722: invalid number
how to solve it?
select remark,
to_number( to_number(REGEXP_SUBSTR (remark, '[[:digit:]]+', 1) ) ||','|| to_number(substr(REGEXP_SUBSTR (remark, ',[^EUR]+', 1) ,2) ) )
from tmp_mape
View 7 Replies
View Related
Dec 23, 2012
i have a problem with my SQL programming which i am learning at the moment. Currently here is my Show how many orders were placed in each month of 2012. (group by question, to char function)
select count(orderdate)
from csorder
group by orderdate;
where the to char function would occur?
tables for reference
CSPRODUCT contains (PRODCODE, PRODNAME, CATCODE, PRICE, PARTOF_PRODCODE)
CSCATEGORY contains (CATECODE, CATNAME)
CSORDER contains (ORDERID, ORDERDATE, CUSTID, PAID)
CSORDERLINE contains (ORDERID, PRODCODE, QUANTITY)
View 3 Replies
View Related
Oct 9, 2013
I have been tasked with producing a list of all non standard characters that are not one of 0-9, a-z, A-Z from a parts table. The list should capture any non-English characters i.e. áóú etc as well as !"£$%^&* etc. These are a small example of the data.
Part_Description
Probengefäss kompl.
Stützring zu Probenehmer
Zargendichtung m.2 Ventillöcher
Pneumatikdichtung m.2 Ventillöcher
Result from above example
ä.üö
View 8 Replies
View Related
Aug 18, 2011
I am trying to compare 2 char columns using trim to avoid space padding
CREATE TABLE TRIAL_A
(ABC CHAR(6));
INSERT ALL
[Code]....
View 11 Replies
View Related
Apr 9, 2013
i trying to pass the char varible to the cursor but it is not taking ,,, if i hardcode the values to the cursor it is taking
here is the detailed program ... why this is not taking and tell me how to pass the values through it..
declare
v_name char(6) ;
cursor c1(c_name char) is
select name, parent,child,status from relation
start with name='%'
connect by prior parent=child
union
[Code]...
View 9 Replies
View Related
Apr 1, 2011
I am using forms 6i and oracle 10g. i want to display a char from database. that means a database string 'Bangladesh' is display from by one char to one char.
and display view right to left first display "B" then "BA" then 'BAN' etc.
View 2 Replies
View Related
May 16, 2008
How to find out lowercase char in a String in a SQL query
for example
"ORAclE" here c and l are lowercase so how can i find out this condition... is there any build in function in oracle?
View 13 Replies
View Related
Oct 28, 2011
using listagg function for more than 8000 char.I did the below sample SQL and in "e_orig" and "d_orig" for upto 4000 char it is working fine but I have to use it for more than 8000 char. and it is giving error,I checked the listagg function is having limitation of 4000 char.I tried but I am unable to achieve this.
select d.dname,d.loc,e.hiredate
,listagg(e.ename,',' ) within group (order by e.deptno) over (partition by e.deptno) as e_orig
,listagg(e.ename, ',') within group (order by e.sal) over (partition by e.deptno) as d_orig
from emp e, dept d
where e.deptno=d.deptno;
[code]....
View 17 Replies
View Related
Jul 6, 2011
I am using an portuguese(brazil) Oracle 11g db,which should have ',' as decimal char. it seems to be working fine when i m trying to get numerical data via select query,but when i am trying to retrive the same data using out parameter of an sproc.I am getting data with '.' as decimal char.
View 2 Replies
View Related
Jul 26, 2012
I want to get the last month of my table “a” (Which is in number format) and after that I want to change it to a date format and insert into my table “b”.
I have already done the max month query:
SELECT MAX(MONTH_ID) FROM Table_a;
SELECT DISTINCT MONTH_ID ---This data is the one that I would like to change format "mon-yyyy"
FROM Table_a
WHERE MONTH_ID = (SELECT MAX(MONTH_ID) FROM Table_a);
I am getting trouble with the to_char function, I have been reviewing how it works and how to handle it.
View 3 Replies
View Related
Oct 12, 2012
From a list of values from a number column, I need to verify is there any values not satisfying number(3).
Ex- I have a column col1 where we have following values
'qwq'
'12.3'
'1'
'15'
Can I write a query to check the value not satisfying number(3) datatype.Eg the query should return
'qwq'
'12.3'
as the above two will not fit in to number(3) datatype columns
View 13 Replies
View Related
Dec 7, 2010
I tried google and most of bind example using number instead of character, ?
I have the code as below:
variable oldId varchar2(5)
exec :oldId :='&1'
variable newId varchar2(5)
exec :newId :='&2'
[Code]...
Since in TAB1, ID is defined as varchar2(5), and I have defined both oldId and newId as varchar2(5) in my code, I wonder why it doesn't work.
It returned this error:
DECLARE
*
ERROR at line 1: ORA-01722: invalid number ORA-06512: at line xx
After supply the value for oldId(val2) and newId(val1)
SQL > @thisScript val1 val2
I use dbms_output.put_line to print the command executed, it seems it is doing
UPDATE TABLE1 SET ID = val1 WHERE ID = val2
without the single quote ('val1'), ('val2'). But if I put in single quotes, the output statement
UPDATE TABLE1 SET ID = ':newId' WHERE ID = ':oldId'
The same bind logic works in SQL prompt
SQL > variable oldId varchar2(5);
SQL > variable newId varchar2(5);
SQL > exec :oldId :='val2'
SQL > exec :newId :='val1'
SQL > UPDATE TABLE1 SET ID = :newId WHERE ID = :oldId;
1 row updated.
I am wondering what should I do then? With or without single quotes?
View 9 Replies
View Related
Jun 16, 2010
I want to add format mask on my field...
my field datatype is char in forms and in database VARCHAR2(30) and I want to add format mask as follows
12345-1234567-1
in format mask of this field property I give it to format mast like as
FMAAAAA"-"AAAAAAA"-"A
when I run the form and when I write and exit from this field then it returns the error.
FRM-40209: Field must be of form FMAAAAA"-"AAAAAAA"-"A
EDIT by VK: Seems your CAPS lock is on or the Shift is stuck.
View 5 Replies
View Related
