on 01-15-2015 3:37 PM
Hello,
as I try to understand some of the concepts of SAP HANA I thought it is a good idea to have a look at the internal attributes. I saw that in M_CS_ALL_COLUMNS all columns are listed. When I made a GROUP BY on INTERNAL_ATTRIBUTE_TYPE with a count(*) I found values for NULL, ROWID, TREX_UDIV, TREX_EXTERNAL_KEY and CONCAT_ATTRIBUTE.
As I could read in several sources all of these values are clear to me:
NULL - it is no internal column
ROWID - Internal unique identifyer of the row
TREX_UDIV - some internal transaction value
TREX_EXTERNAL_KEY - multicolumn primary key index
CONCAT_ATTRIBUTE - Index for multicolumns joins
The problem is that I found another INTERNAL_ATTRIBUTE_TYPE called "UNKNOWN" used in _SYS_REPO and SAPSR1 (BW on HANA). The column names always used following pattern: $_SYS_SHADOW_<COLUMN>$"
Does someone know something about this INTERNAL_COLUMN_TYPE?
Thanks
Patrik
Hello,
The internal attributes having column name pattern $_SYS_SHADOW_*$ seem to belong to full-text-indices. I was able to re-create the same output by executing:
CREATE COLUMN TABLE A (A VARCHAR(10) PRIMARY KEY, B VARCHAR(10));
CREATE FULLTEXT INDEX i ON A(A) FUZZY SEARCH INDEX OFF;
SELECT * FROM M_CS_ALL_COLUMNS WHERE table_name = 'A';
I tested it with latest HANA revision but still UNKNOWN is shown for the internal attribute. I will report this to HANA development.
Best regards,
Michael
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