VClobLen := dbms_lob.getlength(lob_loc => vClob) ĭbms_output.put_line('. 4 hours ago &0183 &32 The columns are as follows: DatabaseName: The name of the database where the query ran. Src_lob => utl_raw.cast_to_varchar2(utl_encode.base64_decode(vBufferRaw))) ĭbms_output.put_line('' || vAmount || '' || vOffset ||ĭbms_output.put_line('Error in dbms_lob.append ' || SQLERRM) VBufferRaw := utl_raw.cast_to_raw(vBufferChar) VBase64Len := dbms_lob.getlength(lob_loc => pBase64) ĭbms_lob.createtemporary(lob_loc => vClob, cache => TRUE) ĭbms_lob.read(lob_loc => pBase64, amount => vAmount, offset => vOffset, MName CONSTANT VARCHAR2(64) := 'decodeClobBase642Clob' ĭbms_output.put_line('Start base64 decoding. PROCEDURE decodeClobBase642Clob(pBase64 IN CLOB, pClob OUT CLOB, Here is the function with i use to decode the base64: How can i tell the utl_encode.base64_decode that its to be decoded into UTF-8? When i now decode (see my function decodeClobBase642Clob) this stream into CLOB it works fine except the special characters because i think the characterset in the database is set to WE8ISO8859P15. I get an UTF-8 stream which is base64 encoded via a CLOB variable in PL/SQL. For example, if you do have excellent filtering for every one of the five related attributes then you should likely have five indexes of the form (SKU_STATUS, RPT_FLAG, ).Īlso, you should consider removing the function calls and instead using inline sql and an alternative delimited string unpacking method.My database version is 11.2.0.2.0 and NLS_CHARACTERSET is set to WE8ISO8859P15 and NLS_NCHAR_CHARACTERSET is set to AL16UTF16. Your goal with these questions is to understand how good a job filtering for each scenario is and based on this, get some idea of if there is any tuning you can do at all and where it makes sense. It is used to work as an IF-THEN-ELSE statement. Consider that you will not be able to use more than one index as an access path to the data even if the user enters multiple values, unless you use BITMAP indexes, but don't get there unless you really have the right kind of system for them. DECODE is an advanced function that the Oracle database supports. You should look deeper into the data statistics of your data and answer these questions:Ģ) what is the number of rows in items for SKU_STATUS='A' and each type of RPT_FLAGģ) how well does each additional parameter improve performance for your delimited strings (rowcount again). In this case, there is no real IO involved for these subqueries so there is not much to optimize there. You are just unpacking a comma delimited string that was given to you as input. The nature of your subqueries is that they do not go to the database for data. in your case I am not sure how much difference any of this will make. Using DYNAMIC SQL, you can build a query that only executes the ones you need based on what was entered. Thus you will always be paying a performance hit for all of them. The point is, that you have five subqueries here that will always be executed, no matter what you do. Using DYNAMIC SQL will put a limit on the scalability of your app, but I would suggest not worse that doing a FTS every time which puts its own limits on scalability.ħ vsql := 'select * from dual where dummy = :1' ġ1 dbms_output.put_line('vdummy_2 = '||vdummy_2||'.') Since this is DYNAMIC SQL I am not sure bind variables will make a difference or not with respect to parsing. Include the FULL/PARALLEL hints as you desire but only for cases where you don't want to use indexes. Construct the query with a WHERE clause that matches the criteria input and then open it. If expr is equal to a search, then Oracle Database returns the corresponding result. If you really want the best query performance, then consider using DYNAMIC SQL. DECODE compares expr to each search value one by one. order codes from a text column (VARCHAR2) in an Oracle database (11g R2) that. Additionally, the decodes as you have will disable indexes anway for these columns. The Oracle REGEXPSUBSTR function allows you to search for a string inside. Indeed, your hint says to do the same table scan regardless of what criteria has been entered so it does not really matter what you do at this point. Thus you have written a worst case query and will pay the performance penalty all the time. You have what is essentially a generic query for which you have no clue what people will enter as criteria.
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