Informatica 8.6 : issue with pmcmd

On AIX 5.3 pmcmd command fails with following error:

$ ./pmcmd

Could not load program ./pmcmd:
Could not load module /u01/Informatica/PowerCenter8.6/server/bin/libpmser.a.
Dependent module /lib/libz.a could not be loaded.
The module has an invalid magic number.
Could not load module pmcmd.
Dependent module /u01/Informatica/PowerCenter8.6/server/bin/libpmser.a could not be loaded.
Could not load module .

This issue has been fixed on one of the latest hotfixes.

To workaround the issue, rename /lib/libz.a so that libz.a which is shipped with Informatica is picked up.

Oracle: Correlated sub-queries effectiveness

During ETL extraction and loading into the star-schema based warehouse, we generally confront with the idea of using outer join or correlated subqeries to add dimension table primary key into the fact table. to clarify more, take an example below:

INSERT INTO w_emp_f
SELECT a.row_wid loc_wid,
b.ename,
b.address
FROM w_emp_fs b
LEFT OUTER JOIN w_location_d a
ON a.datasource_num_id = b.datasource_num_id
AND a.integration_id = b.integration_id


In the example above, row_wid is the unique identifier of the row in Location dimension which needs to be added to Employee Fact table. In reality, there could be up to 30-40 dimensions which need to be joined to Fact table. Outer joining these dimensions is one of the way, but it could be a big overhead if the dimension tables are very large e.g. >2million records. Outer join may not perform.
This is when correlated subqueries come to rescue. We can frame the above load query as follows:
INSERT INTO w_emp_f
SELECT (SELECT row_wid
FROM w_location_d a
WHERE a.datasource_num_id - b.data_source_num_id
AND a.integration_id = b.integration_id) loc_wid,
b.ename,
b.address
FROM w_emp_fs b

Correlated query would only perform good if the dimension columns used in join condition are indexed. This way DB memory can cache the index and return the records from the dimension table fast for each of the record in fact table.

We can choose to segregate dimensions attached to the fact table based on their size. Depending on the memory configuration of the DB system we can hit&trial the size threshold. Dimensions having size lower than this threshold can be outer joined to the fact table and the ones with size higher than the threshold can be pushed to correlated subqueries.

Oracle : Resolving ORA-29275: partial multibyte character

Data might sometimes get corrupted and when accessing can result in error:

In case data volumes are huge, its difficult to pin point the row which is causing this. Though, there is strategy for doing this.

sql > set autotrace traceonly statistics
sql> execute query (select column from table)

This will show you how many rows are processed before the error occured.
e.g.

22787220 rows selected.
.
Statistics
----------------------------------------------------------
6295 recursive calls
0 db block gets
65041120 consistent gets
10050575 physical reads
0 redo size
4195673524 bytes sent via SQL*Net to client
10634511 bytes received via SQL*Net from client
1519151 SQL*Net roundtrips to/from client
108956 sorts (memory)
0 sorts (disk)
22787220 rows processed

So, you can create an duplicate table and delete these many rows ,i.e., 22787220 records using rownum.

then you again run the query and check how many further records are selected before corrupt data is encountered. This way you can single out the data which is causing issue. Generally this kind of data corruption occurs as a result of DB upgrades.

How to fix:

A simple straight way is to delete the record. but that means loosing information.

Following could be done to resolve this:

update table set column=column||'';

i.e., append empty string to the column and that is it...data corruption is fixed without any loss of it.

similar exercise can be done for number type columns. they generally result in end-of-file on communication channel.

you can check the corruption of it by dumping its canonical form.

sql >select column, dump(column) from table.
---- --------------------------------------------------
1 Typ=2 Len=21: 193,2,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1

actual dump should have been "193,2", no trailing "1"s.

these records also can be updated to get them return to normal canonical form.

update table set column=column + 1 - 1;

Oracle : storing strings in multibyte character format

Creating tables using varchar2 datatype by default allocates specified value in bytes. That means if one is storing multi-byte character then you may not be able to store all the characters as some character might be multi-byte i.e taking 2 bytes per character.

We can store multibyte charater strings with specified number of characters using CHAR along with the varchar2 datatype. e.g
Create table lingual ( text varchar2(2o) CHAR);

this way you can store up to 40 bytes or 20 multibyte characters in column text.

To find out how many characters a column of a row has, use length() function. This will return the number of character, multibyte or single byte.

Use lengthb() to determine the number of bytes the column value contains.

Oracle : Finding Non-numeric column record in a table

Find ALL rows where you have non-numeric characters only:

select ROW_SEQ#, STRING#
from TMP_DATA
WHERE length(STRING#)
- Length( TRANSLATE(STRING#, CHR(1)||TRANSLATE(String#,
CHR(1)||'1234567890', CHR(1) ), CHR(1) ) ) > 0
;

Find ALL rows where you have numeric characters only:

Find ALL rows where you have numeric characters only:

select ROW_SEQ#, STRING#
from TMP_DATA
WHERE length(STRING#)
- Length( TRANSLATE(STRING#, CHR(1)||TRANSLATE(String#,
CHR(1)||'1234567890', CHR(1) ), CHR(1) ) ) = 0
;

Oracle: Deleting duplicates from a huge table

delete from t
where rowid in
 (select rid
    from (select rowid rid,
                 row_number() over (partition by KEY_FIELDS
                                      order by rowid) rn
            from t )
                where rn <> 1 );

reference :  http://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:1224636375004

Oracle : ORA-4030 in AIX Environment

If a session tries to allocate pga memory more than the upper limit specified at OS level, it will error out with:
ORA-04030: out of process memory when trying to allocate 249880 bytes (QERHJ hash-joi,kllcqas:kllsltba)

checking the ulimit settings on AIX:
> ulimit -a
time(seconds) unlimited
file(blocks) unlimited
data(kbytes) 256000
stack(kbytes) unlimited
memory(kbytes) 256000
coredump(blocks) 2097151
nofiles(descriptors) 2000

You can see that the maximum memory which can be allocated in chunk is 250M.

This needs to be set to unlimited.

edit /etc/security/limits file and set it as follows:

oracle:
fsize = -1
core = 2097151
cpu = -1
data = -1
rss = -1
stack = -1
stack_hard = -1
nofiles = 2000

here oracle is an OS user using which oracle database is installed. relogin to OS with this user and issue shall be fixed.