Optimizing SQL Insert Performance - GSE Belux

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Summary 48 © 2010 IBM Corporation
Summary – Key Points • Decide whether the data rows should be clustered/appended at the end • Sort inserts into clustering key sequence • Use classic partitioned tablespace and partitioned indexes • Keep the number of indexes to a minimum and drop low value indexes • Tune deferred write thresholds and distributed free space to drive ‘trickle write’ • Use large PRIQTY/SECQTY and large SEGSIZE to reduce frequency of exhaustive space search • Use data compression to minimise log record size • Use faster channel, faster device, DFSMS striping for active log write throughput • Use MEMBER CLUSTER and TRACKMOD NO to reduce spacemap page contention and when using LOCKSIZE ROW to reduce data page contention • Use Identity column, sequence object, GENERATE_UNIQUE() built-in function with caching to efficiently generate a unique key • Important new DB2 9 new feature functions such as large index page size 49 © 2010 IBM Corporation
Page 1 and 2: DB2 for z/OS Optimizing Insert Perf
Page 3 and 4: Agenda • Insert Space Search •
Page 5 and 6: Choice: Performance or Space Reuse
Page 7 and 8: Space Search Steps (Classic Partiti
Page 9 and 10: PBG search algorithm for entire tab
Page 11 and 12: Segmented Tablespace • Segmented
Page 13 and 14: Partitioned Tablespace • Use page
Page 15 and 16: Distributed Free Space • Use dist
Page 17 and 18: TRACKMOD NO • Reduces spacemap co
Page 19 and 20: MEMBER CLUSTER … • Rows inserte
Page 21 and 22: MEMBER CLUSTER, PCTFREE = 0 and FRE
Page 23 and 24: Typical Performance Bottlenecks and
Page 25 and 26: Read and Write I/O for Index and Da
Page 27 and 28: Read and Write I/O for Index and Da
Page 29 and 30: Lock/Latch and Service Task Waits
Page 31 and 32: DB2 Latch Contention • Latch Coun
Page 33 and 34: GENERATE_UNIQUE() • Built-in func
Page 35 and 36: DB2 9 Performance Enhancements 35
Page 37 and 38: Large Index Page Size • Available
Page 39 and 40: Increased Index Look Aside • Prio
Page 41 and 42: Randomised Index Key • Index cont
Page 43 and 44: Identifying Unreferenced Indexes
Page 45 and 46: DB2 10 Performance Enhancements 45
Page 47: V10 Enhancements ... • In-line LO

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