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Learning Objectives
• Just one major objective – to make the majority of unknown/unplanned ad-hoc end-user queries (e.g. BI tool reports’ many “SELECT” statements) execute as fast as is possible – and very efficiently, thus using the least amount of database server resources
We cannot allow big databases to have queries that simply take too long …
Speaker’s Qualifications• Oracle Solutions Product Architect for Quest Software• Chief architect for Quest’s popular “TOAD” product• Oracle DBA for 20+ years, versions 4 through 10g• Worked for Oracle Education & Consulting• Holds several Oracle Masters (DBA & CASE)• BS, MS, PhD in Computer Science and also an MBA• LOMA insurance industry designations: FLMI and ACS• Books
– The TOAD Handbook (Feb 2003)– Oracle DBA Guide to Data Warehousing and Star Schemas (Mar
2003)– The TOAD Pocket Reference 2nd edition (June 2005)
• Articles– Oracle Magazine– Oracle Technology Network (OTN)– Oracle Informant– PC Week (now E-Magazine)– Linux Journal– www.Linux.com
New 2nd Edition – June 2005
About Quest Software• Quest Software (NASDAQ: QSFT)• Founded: 1987• More than 2000 employees in 40 offices: North
America, South America, Europe, Asia, Australia• Application management leader: 75% of Fortune
500• Develop, deploy, manage and maintain
enterprise applications without downtime or business interruption
• Best known in the Oracle community for TOAD, Spotlight, Quest Central, Shareplex, etc.
Know Your Application …
What type of application are you building:
• On Line Transaction Processing (OLTP)
• Operational Data Store (ODS)
• On Line Analytical Processing (OLAP)
• Data Mart / Data Warehouse (DM/DW)
OLTP ODS OLAP DM/DWBusiness Focus Operational Operational
TacticalTactical Tactical
Strategic
End User Tools Client Server Web
Client Server Web
Client Server Client Server Web
DB Technology Relational Relational Cubic Relational
Trans Count Large Medium Small Small
Trans Size Small Medium Medium Large
Trans Time Short Medium Long Long
Size in Gigs 10 – 200 50 – 400 50 – 400 400 - 4000
Normalization 3NF 3NF N/A 0NF
Data Modeling Traditional ER
Traditional ER N/A Dimensional
Application Natures…
Embrace New Concepts
• “Teach Old Dog New Tricks”
• Throw out any OLTP baggage
• Forget OLTP “Golden Rules” X
Star Schema Design
“Star schema” approach to dimensional data modeling was pioneered by Ralph Kimball
Dimensions: smaller, de-normalized tables containing business descriptive columns that end-users query on
Facts: very large tables with primary keys formed from the concatenation of related dimension table foreign key columns, and possessing numerically additive, non-key columns used for calculations during end-user queries
Dimensions
Facts
108th -1010th
103rd -105th
The Ad-Hoc ChallengeThe Ad-Hoc Challenge
How much data would a data miner mine, if a data miner could mine data?
Dimensions: generally queried selectively to find lookup value matches that are used to query against the fact table
Facts: must be selectively queried, since they generally have hundreds of millions to billions of rows – even full table scans utilizing parallel are too big for most systems
Hardware Not CompensateHardware Not Compensate
Often, people have expectation that using expensive hardware is only way to obtain optimal performance for a data warehouse
•CPU•SMP•MPP
•Disk•15,000 RPM•RAID (EMC)
•OS•UNIX•64-bit
•Oracle•OPS / PQO•64-bit
DB Design ParamountDB Design Paramount
In reality, the database design is the key factor to optimal query performance for a data warehouse built as a “Star Schema”
There are certain minimum hardware and software requirements that once met, play a very subordinate role to tuning the database
Golden Rule: get the serial explain plan correct before doing partitioning or PQ
Key Tuning RequirementsKey Tuning Requirements
1. Right version of Oracle
2. Properly tuned Init.Ora
3. Lots of Bitmap Indexes!!!
4. Cost Based Optimizer
5. Statistics and Histograms
6. “Star Transformation” explain plan
Oracle Version ProblemsOracle Version Problems
Oracle 7.X lacks:•True Partitioning of Tables and Indexes•Reliable and Efficient Bitmap Indexes•Histograms for Cost-Based Optimization •“Star Transformation” explain plan
Oracle 8.X lacks:•List Partitioning•Scalable Bitmap Indexes (500+ million)•Scalable Histograms (500+ million)•Bitmap Join Index•Numerous new GORUP & OLAP Functions•ANSI Syntax Support (e.g. ANSI 99 Join)
Oracle 8.X Init.OraOracle 8.X Init.Oraalways_anti_join=HASHalways_semi_join=HASHbitmap_merge_area_size=>16Mbuffer_pool_keep=xM (for bitmap indexes)buffer_pool_recycle=xM (for fact tables)compatible=8.1.7.3.0create_bitmap_area_size>=16Mdb_block_buffers= (1.7G / DB_BLOCK_SIZE) – shared_pool_sizedb_block_size>=16Kdb_file_direct_io_count= MAX_IO_SIZE / DB_BLOCK_SIZEdb_file_multiblock_read_count= MAX_IO_SIZE / DB_BLOCK_SIZEdb_writer_processes=10disk_asynch_io=TRUEhash_area_size>=16Mhash_join_enabled=TRUEhash_multiblock_io_count= MAX_IO_SIZE / DB_BLOCK_SIZEoptimizer_features_enable=8.1.7optimizer_percent_paralell=0 (favor best serial plan – explained later)parallel_automatic_tuning=TRUEparallel_broadcast_enabled=TRUEparallel_max_servers=4 * CPU_COUNT if you have fast disksparallel_min_percent=0query_rewrite_enabled=TRUEsort_area_size>=4Msort_multiblock_read_count= MAX_IO_SIZE / DB_BLOCK_SIZEstar_transformation_enabled=TEMP_DISABLE
Oracle 9.X Init.OraOracle 9.X Init.Ora
compatible=9.2.0.6.0db_block_size>=16Kdb_cache_size=(1.7G / DB_BLOCK_SIZE) – shared_pool_sizedb_file_multiblock_read_count= MAX_IO_SIZE / DB_BLOCK_SIZEdb_keep_cache_size=xM (for bitmap indexes)db_recycle_cache_size=xM (for fact tables)db_writer_processes=20disk_asynch_io=TRUEfilesystemio_options=SETALL (directIO + asynch)hash_join_enabled=TRUElog_parallelism=8optimizer_features_enable=9.2.0parallel_automatic_tuning=TRUEparallel_max_servers=4 * CPU_COUNT if you have fast disksparallel_min_percent=0pga_aggregate_size>=64Mquery_rewrite_enabled=TRUEstar_transformation_enabled=TRUE or TEMP_DISABLEundo_management=AUTOworkarea_size_policy=AUTO
Oracle 10.X Init.OraOracle 10.X Init.Ora
compatible=10.2.0.2.0db_block_size>=16Kdb_file_multiblock_read_count= MAX_IO_SIZE / DB_BLOCK_SIZEdb_keep_cache_size=xM (for bitmap indexes)db_recycle_cache_size=xM (for fact tables)db_writer_processes=20disk_asynch_io=TRUEfilesystemio_options=SETALL (directIO + asynch)optimizer_features_enable=10.2.0parallel_automatic_tuning=TRUEparallel_max_servers=4 * CPU_COUNT if you have fast disksparallel_min_percent=0pga_aggregate_size>=64Mquery_rewrite_enabled=TRUEsga_target_size=1.7G (for 32-bit systems)star_transformation_enabled=TRUE or TEMP_DISABLEundo_management=AUTOworkarea_size_policy=AUTO
Bitmap IndexesBitmap Indexes
All fact table, foreign key columns must have individual bitmap indexes on them
If using Oracle 8.1, then ALTER TABLE MINIMIZE RECORDS_PER_BLOCK to optimize the mapping of bitmaps to rowids
All dimension table, non-key columns should have individual bitmap indexes
Nighttime - 10 B-Tree Indexes
Daytime - 48 Bitmap Indexes!!!
Bit-map indexes– Contrary to widespread belief, can be effective when
there are many distinct column values
– Not suitable for OLTP however
0.01
0.1
1
10
100
1 10 100 1,000 10,000 100,000 1,000,000
Distinct values
Ela
psed tim
e (
s)
Bitmap index B*-Tree index Full table scan
Fact Table IndexesFact Table Indexes
Table Index Type Uniq Column Null---------------- -------------------- ------ ---- -------------------- ----DW_ORDER DW_POS_DAY_B1 BITMAP N PERIOD_ID N
DW_POS_DAY_B2 BITMAP N LOCATION_ID N
DW_POS_DAY_B3 BITMAP N PRODUCT_ID N
DW_POS_DAY_B4 BITMAP N VENDOR_ID N
DW_POS_DAY_PK NORMAL Y PERIOD_ID N NORMAL Y LOCATION_ID N NORMAL Y PRODUCT_ID N NORMAL Y VENDOR_ID N NORMAL Y RECMD_FLAG N NORMAL Y NEW_ITEM_FLAG N
Dimension Table IndexesDimension Table Indexes
Table Index Type Uniq Column Null---------------- -------------------- ------ ---- -------------------- ----DW_VENDOR DW_VENDOR_B02 BITMAP N LEVELX N
DW_VENDOR_B03 BITMAP N VENDOR_CODE N
DW_VENDOR_B05 BITMAP N CITY Y
DW_VENDOR_B06 BITMAP N STATE Y
DW_VENDOR_B07 BITMAP N ZIP N
DW_VENDOR_PK NORMAL Y VENDOR_ID N
DW_VENDOR_U1 NORMAL Y VENDOR_NAME N
Cost Based OptimizerCost Based Optimizer
Statistics and Histograms:
1. First, analyze table delete statistics
2. For dimension tables, estimate statistics for table for all indexes
3. For fact tables, estimate statistics for table for all indexes for all indexed columns size 254 sample 20000 rows
Ready to Rock and RollReady to Rock and Roll
With all our database tuning pre-requisites addressed, we can now rely on Oracle to formulate reasonable explain plans for “Star Schema” data warehouse queries
In fact if we’ve done everything correctly, then table/index partitioning and parallel query will merely eliminate partitions or perform parallel operations on our serial explain plans (i.e. 95%+ identical plans)
Sample Tuning CasesSample Tuning Cases
Oracle 9.2.0.6 / HP-UX 11.11• HP-9000, V2200, 16 CPU, 16 GB RAM• Avg Fact table row count = 600 million
Oracle 8.1.7.3 / HP-UX 10.20• HP-9000, K460, 4 CPU, 4 GB RAM• Avg Fact table row count = 3 million
Oracle 10.1.0.5 / Windows 2003 Server• Quad Xeon, 4 GB RAM• Avg Fact table row count = 3 million
Oracle 10.2.0.2 / Redhat Linux AS 4.0• Quad Xeon, 4 GB RAM• Avg Fact table row count = 3 million
SameExplainPlans!!!
Query: beer and coffee sales for November of 98 in Dallas
Star Transformation
Star Transformation
Star Transformation
Star join performance
0.06
3.43
59.86
0 10 20 30 40 50 60
Elapsed time (s)
STAR hint
Cost Based (no STAR)
Rule Based
3 orders of magnitude difference between best and worst plan
-------------------------------------------------------------------------------------------------------| Operation | Name | Rows | Bytes| Cost | Pstart| Pstop |-------------------------------------------------------------------------------------------------------| SELECT STATEMENT | | 1 | 154 | 34 | | || SORT GROUP BY | | 1 | 154 | 34 | | || HASH JOIN | | 1 | 154 | 29 | | || TABLE ACCESS BY INDEX ROWID | DW_ORDER | 1 | 95 | 17 | | || BITMAP CONVERSION TO ROWIDS | | | | | | || BITMAP AND | | | | | | || BITMAP MERGE | | | | | | || BITMAP KEY ITERATION | | | | | | || TABLE ACCESS BY INDEX ROWID | DW_PERIOD | 1 | 51 | 2 | | || BITMAP CONVERSION TO ROWIDS | | | | | | || BITMAP AND | | | | | | || BITMAP INDEX SINGLE VALUE | DW_PERIOD_B03 | | | | | || BITMAP INDEX SINGLE VALUE | DW_PERIOD_B12 | | | | | || BITMAP INDEX RANGE SCAN | DW_ORDER_B1 | | | | | || BITMAP MERGE | | | | | | || BITMAP KEY ITERATION | | | | | | || TABLE ACCESS BY INDEX ROWID | DW_LOCATION | 1 | 46 | 2 | | || BITMAP CONVERSION TO ROWIDS | | | | | | || BITMAP AND | | | | | | || BITMAP INDEX SINGLE VALUE | DW_LOCATION_B03 | | | | | || BITMAP INDEX SINGLE VALUE | DW_LOCATION_B41 | | | | | || BITMAP INDEX RANGE SCAN | DW_ORDER_B2 | | | | | || BITMAP MERGE | | | | | | || BITMAP KEY ITERATION | | | | | | || TABLE ACCESS BY INDEX ROWID | DW_PRODUCT | 17 | 1K| 10 | | || BITMAP CONVERSION TO ROWIDS | | | | | | || BITMAP AND | | | | | | || BITMAP INDEX SINGLE VALUE | DW_PRODUCT_B03 | | | | | || BITMAP OR | | | | | | || BITMAP INDEX SINGLE VALUE | DW_PRODUCT_B14 | | | | | || BITMAP INDEX SINGLE VALUE | DW_PRODUCT_B14 | | | | | || BITMAP INDEX RANGE SCAN | DW_ORDER_B3 | | | | | || TABLE ACCESS BY INDEX ROWID | DW_PRODUCT | 17 | 1K| 10 | | || BITMAP CONVERSION TO ROWIDS | | | | | | || BITMAP AND | | | | | | || BITMAP INDEX SINGLE VALUE | DW_PRODUCT_B03 | | | | | || BITMAP OR | | | | | | || BITMAP INDEX SINGLE VALUE | DW_PRODUCT_B14 | | | | | || BITMAP INDEX SINGLE VALUE | DW_PRODUCT_B14 | | | | | |-------------------------------------------------------------------------------------------------------
UTLXPLS: Serial Plan, No Partitioning
-------------------------------------------------------------------------------------------------------| Operation | Name | Rows | Bytes| Cost | Pstart| Pstop |-------------------------------------------------------------------------------------------------------| SELECT STATEMENT | | 1 | 154 | 35 | | || SORT GROUP BY | | 1 | 154 | 35 | | || SORT GROUP BY | | 1 | 154 | 35 | | || HASH JOIN | | 1 | 154 | 30 | | || PARTITION RANGE ALL | | | | | 1 | 10 || TABLE ACCESS BY LOCAL INDEX ROWID| DW_ORDER_PART | 0 | 20 | 18 | 1 | 10 || BITMAP CONVERSION TO ROWIDS | | | | | | || BITMAP AND | | | | | | || BITMAP MERGE | | | | | | || BITMAP KEY ITERATION | | | | | | || SORT BUFFER | | | | | | || TABLE ACCESS BY INDEX ROWID| DW_PERIOD | 1 | 51 | 2 | | || BITMAP CONVERSION TO ROWID| | | | | | || BITMAP AND | | | | | | || BITMAP INDEX SINGLE VALU| DW_PERIOD_B03 | | | | | || BITMAP INDEX SINGLE VALU| DW_PERIOD_B12 | | | | | || BITMAP INDEX RANGE SCAN | DW_ORDER_PART_B1 | | | | 1 | 10 || BITMAP MERGE | | | | | | || BITMAP KEY ITERATION | | | | | | || SORT BUFFER | | | | | | || TABLE ACCESS BY INDEX ROWID| DW_LOCATION | 1 | 46 | 2 | | || BITMAP CONVERSION TO ROWID| | | | | | || BITMAP AND | | | | | | || BITMAP INDEX SINGLE VALU| DW_LOCATION_B03 | | | | | || BITMAP INDEX SINGLE VALU| DW_LOCATION_B41 | | | | | || BITMAP INDEX RANGE SCAN | DW_ORDER_PART_B2 | | | | 1 | 10 || BITMAP MERGE | | | | | | || BITMAP KEY ITERATION | | | | | | || SORT BUFFER | | | | | | || TABLE ACCESS BY INDEX ROWID| DW_PRODUCT | 17 | 1K| 10 | | || BITMAP CONVERSION TO ROWID| | | | | | || BITMAP AND | | | | | | || BITMAP INDEX SINGLE VALU| DW_PRODUCT_B03 | | | | | || BITMAP OR | | | | | | || BITMAP INDEX SINGLE VAL| DW_PRODUCT_B14 | | | | | || BITMAP INDEX SINGLE VAL| DW_PRODUCT_B14 | | | | | || BITMAP INDEX RANGE SCAN | DW_ORDER_PART_B3 | | | | 1 | 10 || TABLE ACCESS BY INDEX ROWID | DW_PRODUCT | 17 | 1K| 10 | | || BITMAP CONVERSION TO ROWIDS | | | | | | || BITMAP AND | | | | | | || BITMAP INDEX SINGLE VALUE | DW_PRODUCT_B03 | | | | | || BITMAP OR | | | | | | || BITMAP INDEX SINGLE VALUE | DW_PRODUCT_B14 | | | | | || BITMAP INDEX SINGLE VALUE | DW_PRODUCT_B14 | | | | | |-------------------------------------------------------------------------------------------------------
UTLXPLS: Serial Plan, with Partitioning
----------------------------------------------------------------------------------------------------------------------------------| Operation | Name | Rows | Bytes| Cost | TQ |IN-OUT| PQ Distrib | Pstart| Pstop |----------------------------------------------------------------------------------------------------------------------------------| SELECT STATEMENT | | 1 | 154 | 34 | | | | | || SORT GROUP BY | | 1 | 154 | 34 | 2,03 | P->S | QC (RANDOM)| | || SORT GROUP BY | | 1 | 154 | 34 | 2,02 | P->P | HASH | | || HASH JOIN | | 1 | 154 | 29 | 2,02 | PCWP | | | || TABLE ACCESS BY INDEX ROWID | DW_ORDER | 1 | 95 | 17 | 2,01 | P->P | HASH | | || BITMAP CONVERSION TO ROWIDS | | | | | | | | | || BITMAP AND | | | | | | | | | || BITMAP MERGE | | | | | | | | | || BITMAP KEY ITERATION | | | | | | | | | || TABLE ACCESS BY INDEX ROWID | DW_PERIOD | 1 | 51 | 2 | | | | | || BITMAP CONVERSION TO ROWIDS | | | | | | | | | || BITMAP AND | | | | | | | | | || BITMAP INDEX SINGLE VALUE | DW_PERIOD_B03 | | | | | | | | || BITMAP INDEX SINGLE VALUE | DW_PERIOD_B12 | | | | | | | | || BITMAP INDEX RANGE SCAN | DW_ORDER_B1 | | | | | | | | || BITMAP MERGE | | | | | | | | | || BITMAP KEY ITERATION | | | | | | | | | || TABLE ACCESS BY INDEX ROWID | DW_LOCATION | 1 | 46 | 2 | | | | | || BITMAP CONVERSION TO ROWIDS | | | | | | | | | || BITMAP AND | | | | | | | | | || BITMAP INDEX SINGLE VALUE | DW_LOCATION_B03 | | | | | | | | || BITMAP INDEX SINGLE VALUE | DW_LOCATION_B41 | | | | | | | | || BITMAP INDEX RANGE SCAN | DW_ORDER_B2 | | | | | | | | || BITMAP MERGE | | | | | | | | | || BITMAP KEY ITERATION | | | | | | | | | || TABLE ACCESS BY INDEX ROWID | DW_PRODUCT | 17 | 1K| 10 | | | | | || BITMAP CONVERSION TO ROWIDS | | | | | | | | | || BITMAP AND | | | | | | | | | || BITMAP INDEX SINGLE VALUE | DW_PRODUCT_B03 | | | | | | | | || BITMAP OR | | | | | | | | | || BITMAP INDEX SINGLE VALUE| DW_PRODUCT_B14 | | | | | | | | || BITMAP INDEX SINGLE VALUE| DW_PRODUCT_B14 | | | | | | | | || BITMAP INDEX RANGE SCAN | DW_ORDER_B3 | | | | | | | | || TABLE ACCESS BY INDEX ROWID | DW_PRODUCT | 17 | 1K| 10 | 2,00 | S->P | HASH | | || BITMAP CONVERSION TO ROWIDS | | | | | | | | | || BITMAP AND | | | | | | | | | || BITMAP INDEX SINGLE VALUE | DW_PRODUCT_B03 | | | | | | | | || BITMAP OR | | | | | | | | | || BITMAP INDEX SINGLE VALUE | DW_PRODUCT_B14 | | | | | | | | || BITMAP INDEX SINGLE VALUE | DW_PRODUCT_B14 | | | | | | | | |----------------------------------------------------------------------------------------------------------------------------------
UTLXPLP: Parallel Plan, No Partitioning
----------------------------------------------------------------------------------------------------------------------------------| Operation | Name | Rows | Bytes| Cost | TQ |IN-OUT| PQ Distrib | Pstart| Pstop |----------------------------------------------------------------------------------------------------------------------------------| SELECT STATEMENT | | 1 | 154 | 34 | | | | | || SORT GROUP BY | | 1 | 154 | 34 | 5,03 | P->S | QC (RANDOM)| | || SORT GROUP BY | | 1 | 154 | 34 | 5,02 | P->P | HASH | | || HASH JOIN | | 1 | 154 | 29 | 5,02 | PCWP | | | || PARTITION RANGE ALL | | | | | 5,02 | PCWP | | 1 | 10 || TABLE ACCESS BY LOCAL INDEX ROWID| DW_ORDER_PART | 0 | 20 | 18 | 5,01 | P->P | HASH | 1 | 10 || BITMAP CONVERSION TO ROWIDS | | | | | | | | | || BITMAP AND | | | | | | | | | || BITMAP MERGE | | | | | | | | | || BITMAP KEY ITERATION | | | | | | | | | || SORT BUFFER | | | | | | | | | || TABLE ACCESS BY INDEX ROWID| DW_PERIOD | 1 | 51 | 2 | | | | | || BITMAP CONVERSION TO ROWID| | | | | | | | | || BITMAP AND | | | | | | | | | || BITMAP INDEX SINGLE VALU| DW_PERIOD_B03 | | | | | | | | || BITMAP INDEX SINGLE VALU| DW_PERIOD_B12 | | | | | | | | || BITMAP INDEX RANGE SCAN | DW_ORDER_PART_B1 | | | | | | | 1 | 10 || BITMAP MERGE | | | | | | | | | || BITMAP KEY ITERATION | | | | | | | | | || SORT BUFFER | | | | | | | | | || TABLE ACCESS BY INDEX ROWID| DW_LOCATION | 1 | 46 | 2 | | | | | || BITMAP CONVERSION TO ROWID| | | | | | | | | || BITMAP AND | | | | | | | | | || BITMAP INDEX SINGLE VALU| DW_LOCATION_B03 | | | | | | | | || BITMAP INDEX SINGLE VALU| DW_LOCATION_B41 | | | | | | | | || BITMAP INDEX RANGE SCAN | DW_ORDER_PART_B2 | | | | | | | 1 | 10 || BITMAP MERGE | | | | | | | | | || BITMAP KEY ITERATION | | | | | | | | | || SORT BUFFER | | | | | | | | | || TABLE ACCESS BY INDEX ROWID| DW_PRODUCT | 17 | 1K| 10 | | | | | || BITMAP CONVERSION TO ROWID| | | | | | | | | || BITMAP AND | | | | | | | | | || BITMAP INDEX SINGLE VALU| DW_PRODUCT_B03 | | | | | | | | || BITMAP OR | | | | | | | | | || BITMAP INDEX SINGLE VAL| DW_PRODUCT_B14 | | | | | | | | || BITMAP INDEX SINGLE VAL| DW_PRODUCT_B14 | | | | | | | | || BITMAP INDEX RANGE SCAN | DW_ORDER_PART_B3 | | | | | | | 1 | 10 || TABLE ACCESS BY INDEX ROWID | DW_PRODUCT | 17 | 1K| 10 | 5,00 | S->P | HASH | | || BITMAP CONVERSION TO ROWIDS | | | | | | | | | || BITMAP AND | | | | | | | | | || BITMAP INDEX SINGLE VALUE | DW_PRODUCT_B03 | | | | | | | | || BITMAP OR | | | | | | | | | || BITMAP INDEX SINGLE VALUE | DW_PRODUCT_B14 | | | | | | | | || BITMAP INDEX SINGLE VALUE | DW_PRODUCT_B14 | | | | | | | | |----------------------------------------------------------------------------------------------------------------------------------
UTLXPLP: Parallel Plan, with Partitioning
SQL Plus Timing ResultsSQL Plus Timing Results
Fact Implementation UNIX 2003
Serial, No Partition 9,688 22,344
Serial, with Partition 5,578 11,625
Parallel, No Partition 7,750 17,875
Parallel, with Partition 11,140 25,454
NOTE: specific to my data and user queries
Plethora Table Design OptionsPlethora Table Design Options
Fact Implementation UNIX
Regular “Heap” Table 9,293
Single Column Partition 4,747
Multi Column Partition 4,987
Composite Partition 6,319
Index Organized 12,508
Partition Index Organized 14,902
NOTE: specific to my data and user queries
ConclusionsConclusionsRemember:
•should use Oracle latest Oracle version for best results (optimizer has matured for DW and specifically star queries)
•proper init.ora (i.e. spfile) parameters
•lots and lots of bitmap indexes
•must use statistics and histograms
•shoot for the “Star Transformation”
•Get non-parallel, non-partitioned explain plan right first, then improve upon that with others
•highly recommend SQL tuning tools – like “TOAD Xpert”
