Htree indexes in ext3

HI
Htree indexes are available in ext3 when the dir_index feature is enabled.how to enable / disable this feature ie. dir_index in OEL 5.4?
Regards
Edited by: you on Jan 5, 2010 12:13 PM

I am not an expert on this issue, but tune2fs makes changes at FS level, so I think it will re-scan and re-organize the ENTIRE directories structure ...It makes sense to me that only one kind of algorithm to be used per filesystem...
Basically, Htree is just a "classical" btree ( http://en.wikipedia.org/wiki/B-tree ) which was optimized for filesystems (using hash to group references to multiple leafs and limiting the tree depth to only a couple of levels, according to http://ext2.sourceforge.net/2005-ols/paper-html/node3.html). Now, I couldn't find any thorough explanation of the algorithm, but if you really want more in-depth info, I suggest looking at the source files. I never done this and I guess I never will, cause from the pov of an admin it's kinda useless....

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K.Mandla offers quite a bit of interesting tweaks in the guide "Howto: Set up Hardy for speed", most of it applies to all linux distros.
http://kmandla.wordpress.com/2008/05/04 … for-speed/
If you have come across any interesting information relating to getting faster and better performance from Linux please do not hesitate to post. Thanks.

PrimoTurbo wrote:
I would like this thread to be dedicated to various speed up techniques and performance tweaks for Linux and especially arch.
K.Mandla offers quite a bit of interesting tweaks in the guide "Howto: Set up Hardy for speed", most of it applies to all linux distros.
http://kmandla.wordpress.com/2008/05/04 … for-speed/
If you have come across any interesting information relating to getting faster and better performance from Linux please do not hesitate to post. Thanks.
You will most likely end up wasting a lot of time for very little gain.
There are no miracle solutions, you either use faster apps or buy faster hardware.
The tweaks which are truly interesting without major drawbacks usually make their way on a default system, one way or another.
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Last edited by awayand (2010-01-13 12:44:11)

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Last edited by haxit (2008-08-26 17:54:21)

Which to use - Sy-index or sy-tabix ??

This is what i found out about SY-INDEX and SY-TABIX but which one to use when i want to delete a line of data from an internal table ? I tried both sy-index and sy-tabix and both works fine and returning the expected output for me but which one is better of to use ?
SY-TABIX :- For Internal Table, Current Line Index
SY-INDEX :- For Loops, Current Loop Pass
The below code is where i uses the Delete ..
LOOP AT dmg.
        CONCATENATE
               dmg-dmg00
               dmg-dmg01
               dmg-dmg02
               dmg-dmg03
               dmg-dmg04
               dmg-dmg07
               dmg-dmg08
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Right. Just like what they said upstairs, sy-babix is the best choice.
One more thing is, if you want to concatenate fields of table dmg and append to tli_down1 on by one. You should not use EXIT after delete dmg.
In that case ,only one line can be appended into tli_down1 table.
> The below code is where i uses the Delete ..
>
> LOOP AT dmg.
>         CONCATENATE
>        dmg-dmg00
>         dmg-dmg01
>        dmg-dmg02
>         dmg-dmg03
>        dmg-dmg04
>         dmg-dmg07
>        dmg-dmg08
>         dmg-dmg09 INTO tli_down1 SEPARATED BY '*'.
>   APPEND tli_down1. CLEAR tli_down1.
>       DELETE dmg INDEX sy-index.
>   EXIT.
>     ENDLOOP.

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Please tell me if it is possible to put index's on cubes; are they automatically added or is this something I put on them?
I do not understand index's are they like aggregates?
Need to find info that explains this.
Thanks for the hlep.
Newbie

Indexes are quite different from aggregates.
An Aggregate is a slice of a cube which helps the data retrival on a faster note when a query is executed on a cube. Basically it is kind of a snapshot of KPI's and Business Indicators (Chars) which will be displayed as the initial query run result.
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When loading we delete Bcs during loading it has to look for existing Indexes and try to update so it will effect the Data load performence so we delete and create it will take less time when compared to updating the existing ones.
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I've table that contains about 20 million rows, and I've created index for varchar2(100) column. It works well if I do
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DATA
dbxml> openContainer test.dbxml
dbxml> getDocuments
2 documents found
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Result WITHOUT INDEX
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--- dbxml-2.3.10-original/dbxml/src/dbxml/optimizer/QueryPlanGenerator.cpp     2007-04-18 10:05:24.000000000 +0100
+++ dbxml-2.3.10/dbxml/src/dbxml/optimizer/QueryPlanGenerator.cpp     2007-08-08 11:32:10.000000000 +0100
@@ -1566,11 +1572,12 @@
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+          result.operation = unionOp;
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INDEX vs TABIX

Hi,
Can some body explain the CLEAR difference between Sy-index and Sy-tabix. And one or two small examples. I am little bit confused.
Thanx.

Hi,
SY-INDEX
In a DO or WHILE loop, SY-INDEX contains the number of loop passes including the current pass.
SY-TABIX
Current line of an internal table. SY-TABIX is set by the statements below, but only for index tables. The field is either not set or is set to 0 for hashed tables.
APPEND sets SY-TABIX to the index of the last line of the table, that is, it contains the overall number of entries in the table.
COLLECT sets SY-TABIX to the index of the existing or inserted line in the table. If the table has the type HASHED TABLE, SY-TABIX is set to 0.
LOOP AT sets SY-TABIX to the index of the current line at the beginning of each loop lass. At the end of the loop, SY-TABIX is reset to the value that it had before entering the loop. It is set to 0 if the table has the type HASHED TABLE.
READ TABLE sets SY-TABIX to the index of the table line read. If you use a binary search, and the system does not find a line, SY-TABIX contains the total number of lines, or one more than the total number of lines. SY-INDEX is undefined if a linear search fails to return an entry.
SEARCH <itab> FOR sets SY-TABIX to the index of the table line in which the search string is found.
regards,
madhu

What is" LINE-COL2 = SY-INDEX ** 2."

can u explain what is '' ** "
FIELD-SYMBOLS <FS> LIKE LINE OF ITAB.
DO 4 TIMES.
LINE-COL1 = SY-INDEX.
LINE-COL2 = SY-INDEX ** 2. "what this will do
APPEND LINE TO ITAB.
ENDDO.

Hi sunil,
1 ** means "To the power of"
2. eg. 5 ** 2 = 25
(5 To the power of 2 = 25)
regards,
amit m.

Regarding sy-index

Hi all,
I am trying to get loop count by using sy-index.
But I am not able get exact expected out put.
I am gettig all zeros instead of loop number.
I am sending my code here.
DATA: lv_diff(10) TYPE c,
        lv_erdat1 LIKE sy-datum,
        lv_erdat2 LIKE sy-datum,
        i(15) TYPE c VALUE '1'.
SORT t_ordno BY aufnr.
LOOP AT t_ordno INTO st_ordno.
    READ TABLE t_ordno INTO st_ordno INDEX i.
    lv_erdat1 = st_ordno-erdat.
    i = i + 1.
    READ TABLE t_ordno INTO st_ordno INDEX i.
    lv_erdat2 = st_ordno-erdat.
    i = i + 1.
    CALL FUNCTION 'DAYS_BETWEEN_TWO_DATES'
         EXPORTING
              i_datum_bis = lv_erdat2
              i_datum_von = lv_erdat1
         IMPORTING
              e_tage      = lv_diff.
    WRITE:/ lv_diff,
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    CLEAR: lv_erdat1,lv_erdat2,lv_diff.

use this code
DATA: lv_diff(10) TYPE c      ,
      lv_erdat1 LIKE sy-datum ,
      lv_erdat2 LIKE sy-datum ,
      i(15) TYPE c VALUE '1' ,
      l_tabix type syst-tabix .
SORT t_ordno BY aufnr.
LOOP AT t_ordno INTO st_ordno.
l_tabix = sy-tabix .
READ TABLE t_ordno INTO st_ordno INDEX i.
lv_erdat1 = st_ordno-erdat.
i = i + 1.
READ TABLE t_ordno INTO st_ordno INDEX i.
lv_erdat2 = st_ordno-erdat.
i = i + 1.
CALL FUNCTION 'DAYS_BETWEEN_TWO_DATES'
       EXPORTING
            i_datum_bis = lv_erdat2
            i_datum_von = lv_erdat1
       IMPORTING
            e_tage      = lv_diff.
WRITE:/ lv_diff,
       50 l_tabix.
CLEAR: lv_erdat1,lv_erdat2,lv_diff.

ANY SY-INDEX REFLECT CHANGES WHEN CONTROL BREAK STATEMENT PROCESS

Dear Guru's,
                 I have a requirement where i have to move the values to variable when control break (AT END OF) process. So i want to move the values according to the end of Vendor so for that i want to know is there any sy-index available which reflects changes when Control break (AT end of) process.
LIKE Sy-subrc = 0 when select statement fetches record or sy-tabix is like counter for loop.
Hope to get reply soon.
Regards,
Himanshu Rangappa

Hi,
There is no system Fields for it.
But your requirement can be done with 'AT NEW' and 'AT END' statement.
Refer this sample example,
loop at otab.
    at new module.
      move otab-module to otab2-module.
    ENDAT.
      at END OF effort.
      sum.               "Do your calculations here
      move otab-count to otab2-count.
      append otab2.
    endat.
endloop.

What is the diffrence betweensy-tabix and sy-index

hi
can any one suggest me
what is the diffrence betweensy-tabix and sy-index
Thanks & Regards
kalyan.

Hi Kalyan,
This question has been answered many times on SCN. Please make a search before posting a thread.
Read the Rules of Engagement.
Happy Posting.
Regards,
Chandra Sekhar

Htree indexes in ext3

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