1. How Good Is Your Indexing Strategy?
MICROSOFT DATA PLATFORM MVP
FOUNDER: SQL CRUISE & B-SIDE CONSULTING
SENIOR DBA: SURVEYMONKEY
TIM FORD

2. PASS Board of Directors
WHO IS TIM?
MVP Since 2009
SQL Cruise Since 2010
Author
PASS Board of Directors
Senior DBA

3. CONTACT POINTS thesqlagentman.com SQLCruise.com tim@sqlcruise.com
@sqlagentman @sqlcruise

4. GOALS AGENDA FAMILIARITY WITH INDEX-RELATED SYSTEM OBJECTS
UNDERSTAND HOW THE PIECES FIT TOGETHER
UNDERSTAND WHAT QUESTIONS CAN BE ANSWERED
AGENDA
INTRODUCTION: WHY ARE INDEXES IMPORTANT
HOW DOES INDEXING GET IN THE WAY?
WHAT MAKES FOR A GOOD INDEX?
TOUR THE INDEXING DYNAMIC MANAGEMENT OBJECTS
MY GIFT TO YOU: THE SCRIPTS AND WHAT THEY ANSWER

5. WHY INDEX? PERFORMANCE BOOST ON READ OPERATIONS LESS IO
MORE EFFICIENT QUERY PLANS

6. HOW DOES INDEXING GET IN THE WAY?
Appropriate: we don’t want to index columns that are not used for reads
Fill factor too high and you get page splits; too low and you are not making efficient use of your index space allocated
Fragmentation leads to inefficient index read and write operations – adding time and IO
Locks & Blocks

7. WHAT MAKES FOR A “GOOD” INDEX?
INDEXING STRATEGY
KEY ANALYSIS POINTS
HIGH READ:WRITE RATIO
APPROPRIATENESS
REASONABLE FILL FACTOR
HEALTHY FRAGMENTATION
Appropriate: we don’t want to index columns that are not used for reads
Fill factor too high and you get page splits; too low and you are not making efficient use of your index space allocated
Fragmentation leads to inefficient index read and write operations – adding time and IO

8. INDEXING DMOs TOOLS AND ANALYSIS INDEXING DMOs USAGE COUNTERS
DM_DB_INDEX_USAGE_STATS
PHYSICAL METRICS
DM_DB_INDEX_PHYSICAL_STATS
LOCK/LATCH/SPLIT STATISTICS
DM_DB_INDEX_OPERATIONAL_STATS
MISSING INDEX DMOs
DM_DB_MISSING_INDEX_COLUMNS
DM_DB_MISSING_INDEX_DETAILS
DM_DB_MISSING_INDEX_GROUP_STATS
DM_DB_MISSING_INDEX_GROUPS

9. USAGE STATISTICS SELECT * FROM sys.dm_db_index_usage_stats
Returns cumulative scan, seek, lookup, update counts and last action times for these operations for each heap or index in the database for both user actions as well as system operations against these objects

10. CRITICAL COLUMNS COLUMN NAME WHY IT MATTERS DATABASE_ID IDENTIFICATION
OBJECT_ID
IDENTIFICATION
INDEX_ID
IDENTIFICATION
USER_SEEKS
COUNT OF USER-INITIATED SEEKS
USER_SCANS
COUNT OF USER-INITIATED SCANS
USER_LOOKUPS
COUNT OF USER-INITIATED LOOKUPS
USER_UPDATES
COUNT OF USER-INITIATED WRITES
LAST_USER_SEEK … UPDATE
LAST TIME THIS OPERATION HAPPENED

11. PHYSICAL METRICS
SELECT * FROM sys.dm_db_index_physical_stats (database_id , object_id , index_id , partition_id , ‘limited’ | ‘detailed’ | ‘sampled’)
Returns fragmentation, structural definitions, space usage, and compression metrics for each partition of a table or index in the database

12. CRITICAL COLUMNS COLUMN NAME WHY IT MATTERS DATABASE_ID IDENTIFICATION
OBJECT_ID
IDENTIFICATION
INDEX_ID
IDENTIFICATION
PARTITION_ID
IDENTIFICATION
INDEX_TYPE_DESC
HEAP | CLUSTERED | NON-CLUSTERED
ALLOC_UNIT_TYPE_DESC
LOB OR NON-LOB DATA
AVG_FRAGMENTATION_IN_PCT
FRAGMENTATION METRIC
PAGE_COUNT
SIZE
RECORD_COUNT
HOW MANY RECORDS
AVG_RECORD_SIZE_IN_BYTES
AVERGAGE SIZE OF EACH RECORD

13. OPERATIONAL STATISTICS
SELECT * FROM sys.dm_db_index_operational_stats (database_id , object_id , index_id , partition_id)
Returns cumulative I/O, locking, latching, and access method activity as well as page split metrics for each partition of a table or index in the database

14. CRITICAL COLUMNS COLUMN NAME WHY IT MATTERS DATABASE_ID IDENTIFICATION
OBJECT_ID
IDENTIFICATION
INDEX_ID
IDENTIFICATION
PARTITION_ID
IDENTIFICATION
LEAF_ALLOCATION_COUNT
LEAF-LEVEL PAGE SPLITS
NONLEAF_ALLOCATION_COUNT
NON-LEAF-LEVEL PAGE SPLITS

15. CRITICAL COLUMNS - continued
COLUMN NAME
WHY IT MATTERS
PAGE_LOCK_WAIT_COUNT
NUMBER OF PAGE LOCK WAITS
PAGE_LOCK_WAIT_IN_MS
PAGE LOCK WAITS IN MILLISECONDS
PAGE_LATCH_WAIT_COUNT
NUMBER OF PAGE LATCH WAITS
PAGE_LATCH_WAIT_IN_MS
PAGE LATCH WAITS IN MILLISECONDS
PAGE_IO_LATCH_WAIT_COUNT
NUMBER OF PAGE IO LATCH WAITS
PAGE_IO_LATCH_WAIT_IN_MS
PAGE IO LATCH WAITS IN MILLISECONDS

16. SYSTEM VIEWS TOOLS AND ANALYSIS OBJECT NAME INDEX METADATA
SYS.INDEXES
INDEX COLUMN METADATA
SYS.INDEX_COLUMNS
TABLE OBJECT METADATA
SYS.TABLES
COLUMN METADATA
SYS.COLUMNS
DATA TYPE METADATA
SYS.TYPES

17. INDEX METADATA ECOSYSTEM
database_id
IXPS
IXUS
IXOS
INDEX METADATA ECOSYSTEM
object_id
index_id
DMOs
System Views
sys.tables
sys.indexes
column_id
sys.columns
sys.index_columns
system_type_id
&
user_type_id
KEY
DMV
column
DMF
sys.types
SYSTEM VIEW

18. QUESTIONS… ANSWERED
USAGE Which tables are read from | written to most | least? Which tables have no activity since last restart | rebuild? What are the use patterns for all indexes? PHYSICAL What are my largest indexes? Which indexes are fragmented? Which indexes that are most used for reads most fragmented? PERFORMANCE Which indexes have the most page splits? Which indexes have the most latching | locking time? Which indexes have the highest average latching | locking time per user interaction? Which indexes have the most table lock promotion attempts | successes? Are there any missing indexes that could help reduce latch | lock | IO latch waits? INFORMATIONAL What indexes are on (this) table?
This is where we list the questions from the scripts and the math for what objects are used to answer.

19. CONTACT POINTS thesqlagentman.com SQLCruise.com tim@sqlcruise.com
@sqlagentman @sqlcruise