Unable to create a bitmap index
Hi,
I want to create a bitmap index on one of the colums on a table. I fired following query and it failed.
SQL> CREATE BITMAP INDEX TRANS_N_BITMAPIDX_VEH_PLATFORM ON TRANSACTION_NEW(VEH_PLATFORM) LOCAL;
Error starting at line 2 in command:
CREATE BITMAP INDEX TRANS_N_BITMAPIDX_VEH_PLATFORM ON TRANSACTION_NEW(VEH_PLATFORM) LOCAL
Error at Command Line:2 Column:70
Error report:
SQL Error: ORA-01408: such column list already indexed
01408. 00000 - "such column list already indexed"
*Cause:
*Action:I found there is a combined NORMAL index with VEH_PLATFORM column called ‘IDX$$_30AA00021’. It has following columns
• VEH_PLATFORM
• VEH_MODEL
• MODL_YR_NBR
• VEH_MAKE
• TXN_PROCS_DT
But I was able to create bitmap index on VEH_MODEL,MODL_YR_NBR and VEH_MAKE columns without any error.
Why does it error out for VEH_PLATFORM column?
Regards,
Sam
Hi,
I am sure that BITMAP index is only created for
VEH_MAKE
VEH_MODEL
MODL_YR_NBR
BUILD_REGION
VEH_LINE_SERIES
TRANS_CTG_ID
and not for VEH_PLATFORM.
SQL> SELECT * FROM USER_INDEXES WHERE INDEX_TYPE='BITMAP' AND TABLE_NAME='TRANSACTION_NEW';
INDEX_NAME INDEX_TYPE TABLE_OWNER TABLE_NAME TABLE_TYPE UNIQUENESS COMPRESSION PREFIX_LENGTH TABLESPACE_NAME INI_TRANS MAX_TRANS INITIAL_EXTENT NEXT_EXTENT MIN_EXTENTS MAX_EXTENTS PCT_INCREASE PCT_THRESHOLD INCLUDE_COLUMN FREELISTS FREELIST_GROUPS PCT_FREE LOGGING BLEVEL LEAF_BLOCKS DISTINCT_KEYS AVG_LEAF_BLOCKS_PER_KEY AVG_DATA_BLOCKS_PER_KEY CLUSTERING_FACTOR STATUS NUM_ROWS SAMPLE_SIZE LAST_ANALYZED DEGREE INSTANCES PARTITIONED TEMPORARY GENERATED SECONDARY BUFFER_POOL FLASH_CACHE CELL_FLASH_CACHE USER_STATS DURATION PCT_DIRECT_ACCESS ITYP_OWNER ITYP_NAME PARAMETERS GLOBAL_STATS DOMIDX_STATUS DOMIDX_OPSTATUS FUNCIDX_STATUS JOIN_INDEX IOT_REDUNDANT_PKEY_ELIM DROPPED VISIBILITY DOMIDX_MANAGEMENT SEGMENT_CREATED
TRANS_N_BITMAPIDX_MAKE BITMAP VISUAL TRANSACTION_NEW TABLE NONUNIQUE DISABLED 2 6102 20 305 611 12226 N/A 12226 2208 11-MAY-11 1 1 YES N N N DEFAULT DEFAULT DEFAULT NO YES NO NO NO VISIBLE N/A
TRANS_N_BITMAPIDX_MODEL BITMAP VISUAL TRANSACTION_NEW TABLE NONUNIQUE DISABLED 2 11284 158 71 144 22813 N/A 22813 2321 11-MAY-11 1 1 YES N N N DEFAULT DEFAULT DEFAULT NO YES NO NO NO VISIBLE N/A
TRANS_N_BITMAPIDX_BUILD_REGION BITMAP VISUAL TRANSACTION_NEW TABLE NONUNIQUE DISABLED 2 2911 5 582 1161 5808 N/A 5808 5808 11-MAY-11 1 1 YES N N N DEFAULT DEFAULT DEFAULT NO YES NO NO NO VISIBLE N/A
TRANS_N_BITMAPIDX_MODL_YR_NBR BITMAP VISUAL TRANSACTION_NEW TABLE NONUNIQUE DISABLED 2 2911 5 582 1161 5808 N/A 5808 5808 11-MAY-11 1 1 YES N N N DEFAULT DEFAULT DEFAULT NO YES NO NO NO VISIBLE N/A
TRANS_N_BITMAPIDX_TRANS_CTG_ID BITMAP VISUAL TRANSACTION_NEW TABLE NONUNIQUE DISABLED 2 7547 43 175 359 15457 N/A 15457 2345 11-MAY-11 1 1 YES N N N DEFAULT DEFAULT DEFAULT NO YES NO NO NO VISIBLE N/A
TRANS_N_BITMAPIDX_VEH_LINE_S BITMAP VISUAL TRANSACTION_NEW TABLE NONUNIQUE DISABLED 2 10581 253 41 84 21477 N/A 21477 2247 11-MAY-11 1 1 YES N N N DEFAULT DEFAULT DEFAULT NO YES NO NO NO VISIBLE N/A
6 rows selectedRegards,
Sam
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I have a Fact table and 17 dimension tables linked to it. On each foreign-key in the Fact-Table I have created a BITMAP Index. After that I Analyzed the fact table and made sure that the referential constraints were valid.
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Below query is resulting in a wrong total amount and seems to be cartesian.
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SELECT SUM(F.DOLLARS)
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AND D.ST_ID in ('1','2','3','5') In my situation it seems that when I use the <> (not equal to) symbols in combination with the bitmap indexes, that the result of the sum becomes cartesian and thus incorrect.
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Regards, IlonaAnother strange effect is when I leave out the quotation around the not equal to 4 for the Sales_type id (ST_ID <> 4 in stead op ST_ID <> '4' ) then the totals is perfect.
Query 1 version without quotations around ST_ID:
SELECT SUM(F.DOLLARS)
FROM SALES_FACTS F
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WHERE F.TIME_ID = A.TIME_ID
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AND D.ST_ID <> 4 I still have no clue what causes this effect.
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Hi All,
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31.Jan.09/00:29:41 72783 72783
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TABLESPACE "ETDHUB_EQHUB_INDEX"
SQL> select LATEST_VERSION_FLAG,count(*) from BBO_CORPORATE_ACTIONS group by LATEST_VERSION_FLAG;
L COUNT(*)
N 2265303
Y 1189116I am wondering
1.What can be done to reduce index BLEVEL/HEIGHT? (i assume COALESCE will not help)..Should i rebuild the index?
2.Why BTREE_SPACE is only showing 8028 where dba_segments is showing index size =34 MB?
3.Why PCT_USED is NULL?
Is that so BLEVEL/PCT_USED not relative for BITMAP Indexes?
I found that no query is using this index for last 60 days and performance is getting degraded due to FTS.
Should i REBUILD the index so that i can reduce BLEVEL/HEIGHT/INDEX_SIZE and improve query performance with INDEX ACCESS.
Regards,
Bhavik DesaiBhavik Desai wrote:
You perfectely caught the DML pattern.There are 4 daily ELT jobs which INSERT 300 and UPDATE 250 records/execution.
May i ask you,upon which observation,you point this?Also it would be greate if you tell me how did you calculate 67% PCT_FREE.
This was based on the fact that an update to a single row in a table could result in a copy of an entire bitmap index chunk being made; so you need to leave a lot of space free in the leaf blocks to allow for these copies because you really don't want to cause an index leaf block split to occur - especially since that would tend to cascade up the index and cause a branch block split as well. On this basis, pctfree 51 should be adequate for most cases, but setting it to 67 (a) allows you to do a couple of updates/clones to the same chunk before you hit a problem, and (b) helps to keep the chunks smaller which helps to reduce the undo and redo a bit.
This has just reminded me of a little detail - I am a little surprised by the fact that you got an index into this state in 10.2, because that release of Oracle seems to avoid creating a long chain of clones of the same index chunk when you do a series of small updates, and it is the chain of clones that results in branch blocks split running up the index and exploding it to an enormous height. Has this database been upgraded from 9i (or even 10.1) some time in the fairly recent past ?
>
I still dont understand,
1.Why there is no difference in BTREE_SPACE?
2.Why PCT_USED is NULL?
I've just run a quick test on 10.2.0.1 and 10.2.0.3 creating a table with a y/n/null column and creating a bitmap index on it. The results from index_stats didn't match across versions, and the 10.2.0.3 stats were clearly garbage - very similar to yours. For the moment I would assume that something has been broken in 10.2.0.3 with this use of the validate command.
>
If we consider Franck Pachot's observation,then it would be better to convert the BITMAP to BTREE.Is this a normal bitmap behavior?Randolf's observation about the numbers of rows involved is most relevant: it doesn't look like an index that the optimizer should consider using for anything other than select flag, count(*), and changing from a bitmap to a btree won't make any difference. In other words, unless you can point to an important piece of code and say "it makes tis bit run much better" maybe the index shouldn't exist at all.
Regards
Jonathan Lewis
http://jonathanlewis.wordpress.com
http://www.jlcomp.demon.co.uk
"The temptation to form premature theories upon insufficient data is the bane of our profession."
Sherlock Holmes (Sir Arthur Conan Doyle) in "The Valley of Fear". -
Does XE support Bitmap Indexes?
Hi,
I am trying to create a bitmap index in XE and getting the following error:
ORA-00439: feature not enabled: Bit-mapped indexes
I am guessing this is only available in the enterprise editions of the database or is there some way i can enable this option?
thanks,
BrendenI am guessing this is only available in the enterprise editions of the databaseBitmap indexes are enterprise only. You can find a full list of included and excluded functionality in the XE documentation.
Cheers, APC -
Hi,
I am using Oracle 10.2.0.3.0 on Solaris 5.10.
I have a range based partition table with 60 partitions. This is a fact table. I have to load 60 days data in this table. I have created a partition for each day and the partition key is the date column. I created the table with partition, but didn't create the local bitmap index on the partition key vdate, because as far as I know oracle makes the local bitmap index unusable before the insert and then we have to rebuild it after the load. Is that right?
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For instance, in future, some rows get inserted in an existing partition where the local bitmap index is present, so then I should once again rebuild the index on that partition, because in case of insert Oracle would have disabled it?
In this table there is another column vactivity, which is a foreign key from a dimension. Many queries use this column in there where clause. I would also like to create a bitmap index on this column? On this non partitioned key column, the local bitmap index should be created. Is that right?
Please also suggest as which is more faster, rebuilding a local bitmap index after rendering it unusable, or dropping and recreating it?
Thanks and best regardsThe more I know, the more I know that how little I know. Thanks Jonathan for a very insightful answer. Please clarify some points and thanks for your valuable feedback.
Jonathan Lewis wrote:
Fahd Mirza wrote:
Hi,
I am using Oracle 10.2.0.3.0 on Solaris 5.10.
I have a range based partition table with 60 partitions. This is a fact table. I have to load 60 days data in this table. I have created a partition for each day and the partition key is the date column. I created the table with partition, but didn't create the local bitmap index on the partition key vdate, because as far as I know oracle makes the local bitmap index unusable before the insert and then we have to rebuild it after the load. Is that right?
That may depend on the software you use to load the data, it's not a necessity from the perspective of the database.I am using Oracle Warehouse Builder to load the data into the database.
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So the better strategy is to first load the data in the partition and then create a local bitmap index on that partition, is that right?
Depends on the tools, and whether there is data in the table already - but Oracle will optimise index maintenance for bulk inserts in a way which means that it isn't necessary to worry about dropping/recreating if the index already exists and the table is empty.There is no data in the partitions prior to loading.
You may find that with one index it's more efficient to create the index with a lot of free space (51%, say) and leave it at that while another index works better if you mark unusable and rebuild.
Would you please elaborate on this point?
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In this table there is another column vactivity, which is a foreign key from a dimension. Many queries use this column in there where clause. I would also like to create a bitmap index on this column? On this non partitioned key column, the local bitmap index should be created. Is that right?
Your question raise more questions:
a) Does this mean you are only going to have a maximum of two bitmap indexes on this fact table with 60 million rows ? That doesn't sound like it's enough indexes.No, I will create local bitmap indexes on other columns too, which are likely to be used in the adhoc queries.
b) Are you hoping that the vactivity bitmap index will protect you against foreign key locking ? It won't. This (in part) is why people tend to set FK's to disable, novalidate, rely in data warehouses, they want bitmap indexes not btree indexesActually I haven't created the FK constraint.
d) Going back to the bitmap index on the date - is this column storing values that are date-only, or is it storing "date with time". If it's date-only then you've only got one date per partition and the index is a waste of space and processing overhead.The datatype of the column vdate is number. Actually it is refering to the pk of time dimension, in which we have preloaded the dates for the next ten years. Would the index be a total waste on this column?
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Please also suggest as which is more faster, rebuilding a local bitmap index after rendering it unusable, or dropping and recreating it?
Here is the table. I have omitted many partitions for the sake of brevity:
CREATE TABLE CDR
CLNG_NMBR NUMBER,
CL_RFRNC_NMBR VARCHAR2(100 BYTE),
DT_KY NUMBER,
TM_KY NUMBER,
HRLY_KY NUMBER,
ACTVTY_KY NUMBER,
INS_DT DATE,
SRVC_ID VARCHAR2(100 BYTE),
MSC_ADRS VARCHAR2(100 BYTE),
TRF_ID NUMBER,
CL_TYP NUMBER,
LCTN_INFRMTN VARCHAR2(100 BYTE),
LCTN_KY NUMBER,
SRC_CLNG_NMBR VARCHAR2(50 BYTE),
ACTVTY_CL_TP VARCHAR2(100 CHAR)
PARTITION BY RANGE(DT_KY)
PARTITION DAY_20DEC2009 VALUES LESS THAN (4153),
PARTITION DAY_21DEC2009 VALUES LESS THAN (4154),
PARTITION DAY_22DEC2009 VALUES LESS THAN (4155),
PARTITION DAY_23DEC2009 VALUES LESS THAN (4156),
PARTITION DAY_24DEC2009 VALUES LESS THAN (4157),
PARTITION DAY_25DEC2009 VALUES LESS THAN (4158),
PARTITION DAY_26DEC2009 VALUES LESS THAN (4159),
PARTITION DAY_27DEC2009 VALUES LESS THAN (4160),
PARTITION DAY_28DEC2009 VALUES LESS THAN (4161),
PARTITION DAY_31DEC2011 VALUES LESS THAN (4894),
PARTITION DAY_END_PART VALUES LESS THAN (MAXVALUE)
TABLESPACE cdr
PCTUSED 0
PCTFREE 10
INITRANS 1
MAXTRANS 255
STORAGE (
INITIAL 80K
MINEXTENTS 1
MAXEXTENTS UNLIMITED
PCTINCREASE 0
BUFFER_POOL DEFAULT
NOLOGGING
NOCOMPRESS
NOCACHE
NOPARALLEL
MONITORING;Many many thanks and best regards
Fahd
Edited by: Fahd Mirza on Jun 3, 2010 2:00 PM
Edited by: Fahd Mirza on Jun 3, 2010 2:03 PM
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