Could people please let me know if there are any issues with setting Oracle 10g NLS Parameters at database level, specifically the NLS_TERRITORY to the country I am in together with setting the timezone to UTC.
Will there be any conflicts b/c as the moment, our NLS_TERRITORY is set to AMERICA which is not correct?
Thanks.
With Oracle, you must be cautious with the NLS parameters in general. Documentation is always a good idea:
NLS / Globalization stuff
Note that the NLS_TERRITORY parameter is derived from NLS_LANG. So, you should be able to affect the NLS_TERRITORY parameter by changing NLS_LANG. (This should be synched up in any case.)
After you get through that (please do read it), you will probably be thinking "Hey, we have existing data, will we need to perform any conversions on it after changing the parameter?"
TAKE A BACKUP! BEFORE CHANGING
THE PARAMETER. PLEASE
And yes, you may have to perform some data conversion, depending on how things have been stored, and what territory you change to.
Also keep in mind that any client software that uses this database should have its NLS_LANG (especially the characterset portion of it) set the same as the database - otherwise data can get mangled.
What do you mean by "NLS Parameters at database level, specifically the NLS_TERRITORY"?
If you mean the parameters showing up in NLS_DATABASE_PARAMETERS, then these cannot be changed once the database is created. However, these particular parameters (except NLS_[NCHAR]_CHARACTERSET) are used only in CHECK constraints and a few other expressions that need to remain constant throughout the life of a database (e.g. VPD). Hence, it seldom matters to what NLS_TERRITORY in NLS_DATABASE_PARAMETERS is set to.
Related
I would like to make specific INSTANCE of Oracle Database 11g Enterprise Edition CASE INSENSITIVE. Cany anyone let me know if this is possible. I already read few blogs where whole DB can be made CASE INSENSITIVE but for specific instance didn't get any idea.
You need to play around with NLS_SORT, NLS_COMP parameters. But don't directly implement in production, as you might just hit performance issues if you do not do the extra bit of work required.
I am not sure what you mean by "a specific instance". Is it a RAC environment? Do you want one of the nodes to always have case insensitive sessions?
Anyway, you can do it at SESSION level as well as SYSTEM level. But do you really want to implement the HARD way at SYSTEM level?
For example, at session level :
SQL> alter session set nls_comp='LINGUISTIC';
Session altered
SQL> alter session set nls_sort='BINARY_CI';
Session altered
At system level :
You could have a AFTER LOGON TRIGGER and execute the alter session statements. Eek, but that would be killing the performance. You will have to figure out where all you need to create case-insensitive function-based indexes. In my experience, I have always seen case-insensitive search to be slower, no matter you have the required imdex at place.
You can have a look at my article for detailed explanation, http://lalitkumarb.wordpress.com/2014/01/22/oracle-case-insensitive-sorts-compares/
I'm querying from a 10g database using a dblink to an 8i database.
select col1, col2 ... from table#my_dblink_to_8i
8i charset is IW8ISO8859P8
10g charset is WE8MSWIN1252
the data is coming out as gibrish. I've tried all of variations I can think of
to_char(col1)
cast(col1 as nchar(4))
cast(col1 as nvarchar2(4))
cast(col1 as char(4))
cast(col1 as varchar2(4))
convert(col1, 'WE8MSWIN1252', 'IW8ISO8859P8')
convert(convert(col1,'UTF8','IW8ISO8859P8'),'WE8MSWIN1252','UTF8')
all returning with either gibrish or
ORA-12704: character set mismatch
ORA-02063: preceding line from OTHERDB
any suggestions ?
Is there an intermediate charset I can convert to ?
Yes, this is a known problem that sometimes occurs. I remember the first time experiencing it using a database link between two identical Oracle 7 version and then seeing it back in 9 when using Oracle 8.1.5.
It can not always be solved. Oracle development does not seem to test as intensively with non-US characters as with US characters.
The first thing you can try is to check the EXACT versions of Oracle 8i in use. Check that the server version is 8.1.7 or newer (such as 8.1.7.4). With 8.1.5 there are known problems, I think to recall that that is the first version to do AL32UTF8.
Also check the version of the SQL*Net client installation (if you are using a separate installation, I don't think so). It must be 8.1.7 or newer also.
Also check that the characters are available in BOTH character sets. They are largely identical, but not completely. I think the 8859P8 is an international without Europ-support, whereas MSWIN1252 is something of Microsoft.
Check the NLS_LANG on all nodes in between and that the database character set is correctly configured. Make sure they are correct. The interim nodes you can change to AL32UTF8. SQL*net does no character conversion but also no checks when the client and server talk the same characterset, so bugs in the characterset setup can slumber for years.
After testing those, you might want to try convert to AL32UTF instead of UTF8 (I think it was already available by 8, don't know sure, but maybe only mainstream supported on 9i).
As a last resort, do the character conversion yourself. Use a procedure to transport it binary to the caller and do the conversion on the receiving 10g database.
Or use an ETL tool like Kettle, spooling to text files as interim or alike.
I hope this answers your question. If not, please help me with some samples of the gibberish (transporting us7ascii texts, more advanced texts, and the results of out varchar2 parameters called across dblink). If yes, please let me know too. You have a intriguing question!
I am comparing results of two different JDBC drivers of oracle with the help of oracle's SQL tracing capabilities. I am using TKProf to format the results.
When I look at the output of TKProf sometimes I see parameters named prefixed with 'v':
WHERE start_time BETWEEN :v0 AND :v1
At other instances the parameters are not prefixed:
WHERE start_time BETWEEN :1 AND :2
I suspect that in second case, query optimizer is not picking some indices.
Is there a hint in the naming convention of parameters?
I'm certainly not an expert in how the JDBC drivers talk to the database. With luck, someone else will provide that detail.
I believe, though, that the parameter names shouldn't mean anything. That should just be what the particular driver decides to call them when it's sending the query to the database. But if you can peek at the actual values of the bind variables, that might tell you something. My concern would be that one driver is setting it up so the values have to go through a cast on the way to running the query, which could affect index use.
They're private bind variable names picked by the client software; possibly in your Java code the query has between ? and ? which has to be translated to something Oracle will understand. The names are almost irrelevant - certainly nothing to do with indexes or optimisation. I say 'almost' because I'm not sure if Oracle will see them as the same query, or will do separate hard parses of each.
We have a requirement to store char data of different language in the same db schema. Oracle 10g is our DB. I am hoping that someone who have already done this would give me more specific instructions on how to i18n enable a oracle 10g db. We just need to store the data from multiple locales as well as collation (hoping all major db's support this) support at the db level. We doesn't need formatting of dates, datetime, numbers, currency etc.
I read some documentation on oracle's i18n support but somewhat confused about their many nls_* properties. Should I be using nls_lang or nls_language or NLS_CHARACTERSET.....
Assuming that you are building the database from scratch, not trying to retrofit an existing database which introduces other problems.
In the database, you need to ensure that the database character set supports all the characters you want to store. Presumably, that means setting the NLS_CHARACTERSET of the database to AL32UTF8. Personally, I prefer to set NLS_LENGTH_SEMANTICS to CHAR as well. That changes the default behavior of a VARCHAR2(n) to allocate n characters of storage rather than n bytes. Since AL32UTF8 is a variable-length character set, using byte semantics is generally problematic because you either have to declare fields that are 3 times as long and end up with different users being able to enter a different number of characters in the same field.
NLS_LANG is a client setting. That identifies the character set that the client is going to request the data be converted into. That generally depends on the code page of the operating system.
I've been developing a DotNet project on oracle (Ver 10.2) for the last couple of months and was using Varchar2 for my string data fields. This was fine and when navigating the project page refreshes were never more than a half second if even (it's quiet a data intensive project). The data is referenced from 2 different schemas, one a centralised store of data and one of which is my own. Now the centralised schema will be changing to be unicode compliant (but hasn't yet) so all Varchar2 fields will become NVarchar2, in preparation for this I changed all the fields in my schema to be NVarchar2 and since then performance has been horrible .. up to 30/40 second page refreshes.
Could this be because Varchar2 fields in the centralised schema will be joined against NVarchar2 fields in my schema on some stored procedures. I know NVarchar2 is twice the size of Varchar2 but that wouldn't explain the sudden massive change. As I said any tips for what to look for to improve would be great, if I haven't explained the scenario well enough do ask for more information.
Firstly, do a
select * from v$nls_parameters where parameter like '%SET%';
Character sets can be complicated. You can have single-byte charactersets, fixed-size multibyte character set sand variable-sized multi-byte character sets. See the unicode descriptions here
Secondly, if you are joining a string in a single-byte characterset to a string in a two-byte characters set, you have a choice. You can do a binary/byte comparison (which generally won't match anything if you compare between a single-byte character set and a two-byte characterset). Or you can do a linguistic comparison, which will generally mean some CPU cost, as one value is converted into another, and often the failure to use an index.
Indexes are ordered, A,B,C etc. But a character like Ä may fall in different places depending on the Linguistic order. Say the index structure puts Ä between A and B. But then you do a linguistic comparison. The language of that comparison may put Ä after Z, in which case the index can't be used. (Remember your condition could be a BETWEEN rather than an = ).
In short, you'll need a lot of preparation, both in your schema and the central store, to enable efficient joins between different charactersets.
It is difficult to say anything based on what you have provided. Did you manage to check if the estimated cardinalities and/or explain plan changed when you changed the datatype to NVARCHAR2? You may want to read the following blog post to see if you can find a lead
http://joze-senegacnik.blogspot.com/2009/12/cbo-oddities-in-determing-selectivity.html
It is likely no longer able to use indexes that it previously could. As Narendra suggests check the explain plan to see what changed. It is possible that once the centeralized store is changed the indexes will again be usable. I suggest testing that path.
Setting the NLS_LANG initialization parameter properly is essential to proper data conversion. The character set that is specified by the NLS_LANG initialization parameter should reflect the setting for the client operating system. Setting NLS_LANG correctly enables proper conversion from the client operating system code page to the database character set. When these settings are the same, Oracle assumes that the data being sent or received is encoded in the same character set as the database character set, so no validation or conversion is performed. This can lead to corrupt data if conversions are necessary.