all, the COSTEDEVENT table is IOT and and COSTEDEVENT_PK is IOT primary key index and COSTEDEVENT_UK1 is secondary of IOT index my question: why oracle assumption to take COSTEDEVENT_UK1 which is higher clustering factor but lesser in leaf blocks. i guess oracle will assume that smaller leaf blocks is better than the higher one. from this 10053, we could see that resources for cpu & io is small than highr leaf blocks. any thought????? SELECT ...................... FROM e WHERE ................ ******************************************* Peeked values of the binds in SQL statement ******************************************* bind 0: dty=2 mxl=22(22) mal=00 scl=00 pre=00 oacflg=03 oacfl2=800000 size=96 offset=0 bfp=ffffffff7ba79f80 bln=22 avl=00 flg=05 bind 1: dty=2 mxl=22(22) mal=00 scl=00 pre=00 oacflg=03 oacfl2=800000 size=0 offset=24 bfp=ffffffff7ba79f98 bln=22 avl=00 flg=01 bind 2: dty=2 mxl=22(22) mal=00 scl=00 pre=00 oacflg=03 oacfl2=800000 size=0 offset=48 bfp=ffffffff7ba79fb0 bln=22 avl=00 flg=01 bind 3: dty=2 mxl=22(22) mal=00 scl=00 pre=00 oacflg=03 oacfl2=800000 size=0 offset=72 bfp=ffffffff7ba79fc8 bln=22 avl=00 flg=01 *************************************** Column Usage Monitoring is ON: tracking level = 1 *************************************** QUERY BLOCK SIGNATURE ********************* qb name was generated signature (optimizer): qb_name=SEL$1 nbfros=1 flg=0 fro(0): flg=0 objn=197782 hint_alias="COSTEDEVENT"@"SEL$1" *************************************** BASE STATISTICAL INFORMATION *********************** Table stats Table: COSTEDEVENT Alias: COSTEDEVENT (Using composite stats) TOTAL :: CDN: 296160700 NBLKS: 15040307 AVG_ROW_LEN: 261 Index stats Index: COSTEDEVENT_PK COL#: 1 2 3 4 5 USING COMPOSITE STATS TOTAL :: LVLS: 3 #LB: 15040307 #DK: 361175084 LB/K: 1 DB/K: 1 CLUF: 0 Index: COSTEDEVENT_UK1 COL#: 2 5 USING COMPOSITE STATS TOTAL :: LVLS: 3 #LB: 2961679 #DK: 360905528 LB/K: 1 DB/K: 1 CLUF: 20447015 _OPTIMIZER_PERCENT_PARALLEL = 0 *************************************** SINGLE TABLE ACCESS PATH COLUMN: ACCOUNT_NU(VARCHAR2) Col#: 1 Table: COSTEDEVENT Alias: COSTEDEVENT Size: 8 NDV: 47616 Nulls: 0 Density: 2.1001e-05 COLUMN: EVENT_TYPE(NUMBER) Col#: 4 Table: COSTEDEVENT Alias: COSTEDEVENT Size: 2 NDV: 18 Nulls: 0 Density: 5.5556e-02 Min: 1 Max: 29 COLUMN: EVENT_ATTR(VARCHAR2) Col#: 23 Table: COSTEDEVENT Alias: COSTEDEVENT Size: 14 NDV: 1827 Nulls: 402372 Density: 5.4735e-04 COLUMN: EVENT_SEQ(NUMBER) Col#: 2 Table: COSTEDEVENT Alias: COSTEDEVENT Size: 5 NDV: 5 Nulls: 0 Density: 2.0000e-01 Min: 70916001 Max: 71011001 TABLE: COSTEDEVENT Alias: COSTEDEVENT Original Card: 296160700 Rounded: 1 Computed: 0.01 Non Adjusted: 0.01 Access Path: index (index-ffs) Index: COSTEDEVENT_PK rsc_cpu: 107108643882 rsc_io: 2604638 ix_sel: 0.0000e+00 ix_sel_with_filters: 1.0000e+00 Access Path: index-ffs Resc: 2616210 Resp: 2616210 Access Path: index (no start/stop keys) Index: COSTEDEVENT_PK rsc_cpu: 107112578517 rsc_io: 15040859 ix_sel: 1.0000e+00 ix_sel_with_filters: 5.8337e-08 OPTIMIZER PERCENT INDEX CACHING = 100 Access Path: index (index-only) Index: COSTEDEVENT_UK1 rsc_cpu: 1322405301 rsc_io: 0 ix_sel: 9.0000e-03 ix_sel_with_filters: 9.0000e-03 BEST_CST: 22.43 PATH: 4 Degree: 1 *************************************** OPTIMIZER STATISTICS AND COMPUTATIONS *************************************** GENERAL PLANS *********************** Join order[1]: COSTEDEVENT[COSTEDEVENT]#0 Best so far: TABLE#: 0 CST: 22 CDN: 1 BYTES: 261 (newjo-stop-1) k:0, spcnt:0, perm:1, maxperm:80000 Final - All Rows Plan: JOIN ORDER: 1 CST: 22 CDN: 1 RSC: 22 RSP: 22 BYTES: 261 IO-RSC: 1 IO-RSP: 1 CPU-RSC: 198360795 CPU-RSP: 198360795 *** 2007-09-20 23:20:37.432 QUERY SELECT /*+ index(e COSTEDEVENT_PK) */ FROM e WHERE .................. ******************************************* Peeked values of the binds in SQL statement ******************************************* bind 0: dty=2 mxl=22(22) mal=00 scl=00 pre=00 oacflg=03 oacfl2=800000 size=96 offset=0 bfp=ffffffff7ba79f80 bln=22 avl=00 flg=05 bind 1: dty=2 mxl=22(22) mal=00 scl=00 pre=00 oacflg=03 oacfl2=800000 size=0 offset=24 bfp=ffffffff7ba79f98 bln=22 avl=00 flg=01 bind 2: dty=2 mxl=22(22) mal=00 scl=00 pre=00 oacflg=03 oacfl2=800000 size=0 offset=48 bfp=ffffffff7ba79fb0 bln=22 avl=00 flg=01 bind 3: dty=2 mxl=22(22) mal=00 scl=00 pre=00 oacflg=03 oacfl2=800000 size=0 offset=72 bfp=ffffffff7ba79fc8 bln=22 avl=00 flg=01 *************************************** Column Usage Monitoring is ON: tracking level = 1 *************************************** QUERY BLOCK SIGNATURE ********************* qb name was generated signature (optimizer): qb_name=SEL$1 nbfros=1 flg=0 fro(0): flg=0 objn=197782 hint_alias="COSTEDEVENT"@"SEL$1" *************************************** BASE STATISTICAL INFORMATION *********************** Table stats Table: COSTEDEVENT Alias: COSTEDEVENT (Using composite stats) TOTAL :: CDN: 296160700 NBLKS: 15040307 AVG_ROW_LEN: 261 Index stats Index: COSTEDEVENT_PK COL#: 1 2 3 4 5 USING COMPOSITE STATS TOTAL :: LVLS: 3 #LB: 15040307 #DK: 361175084 LB/K: 1 DB/K: 1 CLUF: 0 Index: COSTEDEVENT_UK1 COL#: 2 5 USING COMPOSITE STATS TOTAL :: LVLS: 3 #LB: 2961679 #DK: 360905528 LB/K: 1 DB/K: 1 CLUF: 20447015 _OPTIMIZER_PERCENT_PARALLEL = 0 *************************************** SINGLE TABLE ACCESS PATH COLUMN: ACCOUNT_NU(VARCHAR2) Col#: 1 Table: COSTEDEVENT Alias: COSTEDEVENT Size: 8 NDV: 47616 Nulls: 0 Density: 2.1001e-05 COLUMN: EVENT_TYPE(NUMBER) Col#: 4 Table: COSTEDEVENT Alias: COSTEDEVENT Size: 2 NDV: 18 Nulls: 0 Density: 5.5556e-02 Min: 1 Max: 29 COLUMN: EVENT_ATTR(VARCHAR2) Col#: 23 Table: COSTEDEVENT Alias: COSTEDEVENT Size: 14 NDV: 1827 Nulls: 402372 Density: 5.4735e-04 COLUMN: EVENT_SEQ(NUMBER) Col#: 2 Table: COSTEDEVENT Alias: COSTEDEVENT Size: 5 NDV: 5 Nulls: 0 Density: 2.0000e-01 Min: 70916001 Max: 71011001 TABLE: COSTEDEVENT Alias: COSTEDEVENT Original Card: 296160700 Rounded: 1 Computed: 0.01 Non Adjusted: 0.01 Access Path: index (no start/stop keys) Index: COSTEDEVENT_PK rsc_cpu: 107112578517 rsc_io: 15040859 ix_sel: 1.0000e+00 ix_sel_with_filters: 5.8337e-08 BEST_CST: 2258584.64 PATH: 4 Degree: 1 *************************************** OPTIMIZER STATISTICS AND COMPUTATIONS *************************************** GENERAL PLANS *********************** Join order[1]: COSTEDEVENT[COSTEDEVENT]#0 Best so far: TABLE#: 0 CST: 2258585 CDN: 1 BYTES: 261 (newjo-stop-1) k:0, spcnt:0, perm:1, maxperm:80000 Final - All Rows Plan: JOIN ORDER: 1 CST: 2258585 CDN: 1 RSC: 2258585 RSP: 2258585 BYTES: 261 IO-RSC: 2256129 IO-RSP: 2256129 CPU-RSC: 22730551767 CPU-RSP: 22730551767 *** 2007-09-20 23:23:09.976 QUERY SELECT /*+ parallel_index(e COSTEDEVENT_PK) */ FROM e WHERE ................ ******************************************* Peeked values of the binds in SQL statement ******************************************* bind 0: dty=2 mxl=22(22) mal=00 scl=00 pre=00 oacflg=03 oacfl2=800000 size=96 offset=0 bfp=ffffffff7ba79f80 bln=22 avl=00 flg=05 bind 1: dty=2 mxl=22(22) mal=00 scl=00 pre=00 oacflg=03 oacfl2=800000 size=0 offset=24 bfp=ffffffff7ba79f98 bln=22 avl=00 flg=01 bind 2: dty=2 mxl=22(22) mal=00 scl=00 pre=00 oacflg=03 oacfl2=800000 size=0 offset=48 bfp=ffffffff7ba79fb0 bln=22 avl=00 flg=01 bind 3: dty=2 mxl=22(22) mal=00 scl=00 pre=00 oacflg=03 oacfl2=800000 size=0 offset=72 bfp=ffffffff7ba79fc8 bln=22 avl=00 flg=01 *************************************** PARAMETERS USED BY THE OPTIMIZER ******************************** ************************************* PARAMETERS WITH ALTERED VALUES ****************************** sort_area_size = 0 db_file_multiblock_read_count = 128 optimizer_index_cost_adj = 15 optimizer_index_caching = 100 ************************************* PARAMETERS WITH DEFAULT VALUES ****************************** optimizer_mode_hinted = false optimizer_features_hinted = 0.0.0 parallel_execution_enabled = true parallel_query_forced_dop = 0 parallel_dml_forced_dop = 0 parallel_ddl_forced_degree = 0 parallel_ddl_forced_instances = 0 _query_rewrite_fudge = 90 optimizer_features_enable = 10.1.0.5 _optimizer_search_limit = 5 cpu_count = 72 active_instance_count = 1 parallel_threads_per_cpu = 2 hash_area_size = 0 bitmap_merge_area_size = 1048576 sort_area_retained_size = 0 _sort_elimination_cost_ratio = 0 _optimizer_block_size = 8192 _sort_multiblock_read_count = 2 _hash_multiblock_io_count = 0 _optimizer_max_permutations = 2000 pga_aggregate_target = 9437184 KB _pga_max_size = 204800 KB _sort_space_for_write_buffers = 1 _query_rewrite_maxdisjunct = 257 _smm_auto_min_io_size = 56 KB _smm_auto_max_io_size = 248 KB _smm_min_size = 1024 KB _smm_max_size = 102400 KB _smm_px_max_size = 2831154 KB _cpu_to_io = 0 _optimizer_undo_cost_change = 10.1.0.5 parallel_query_mode = enabled parallel_dml_mode = disabled parallel_ddl_mode = enabled optimizer_mode = all_rows sqlstat_enabled = false _optimizer_percent_parallel = 101 _always_anti_join = choose _always_semi_join = choose _optimizer_mode_force = true _partition_view_enabled = true _always_star_transformation = false _query_rewrite_or_error = false _hash_join_enabled = true cursor_sharing = exact _b_tree_bitmap_plans = true star_transformation_enabled = false _optimizer_cost_model = choose _new_sort_cost_estimate = true _complex_view_merging = true _unnest_subquery = true _eliminate_common_subexpr = true _pred_move_around = true _convert_set_to_join = false _push_join_predicate = true _push_join_union_view = true _fast_full_scan_enabled = true _optim_enhance_nnull_detection = true _parallel_broadcast_enabled = true _px_broadcast_fudge_factor = 100 _ordered_nested_loop = true _no_or_expansion = false _system_index_caching = 0 _disable_datalayer_sampling = false query_rewrite_enabled = true query_rewrite_integrity = enforced _query_cost_rewrite = true _query_rewrite_2 = true _query_rewrite_1 = true _query_rewrite_expression = true _query_rewrite_jgmigrate = true _query_rewrite_fpc = true _query_rewrite_drj = true _full_pwise_join_enabled = true _partial_pwise_join_enabled = true _left_nested_loops_random = true _improved_row_length_enabled = true _index_join_enabled = true _enable_type_dep_selectivity = true _improved_outerjoin_card = true _optimizer_adjust_for_nulls = true _optimizer_degree = 0 _use_column_stats_for_function = true _subquery_pruning_enabled = true _subquery_pruning_mv_enabled = false _or_expand_nvl_predicate = true _like_with_bind_as_equality = false _table_scan_cost_plus_one = true _cost_equality_semi_join = true _default_non_equality_sel_check = true _new_initial_join_orders = true _oneside_colstat_for_equijoins = true _optim_peek_user_binds = true _minimal_stats_aggregation = true _force_temptables_for_gsets = false workarea_size_policy = auto _smm_auto_cost_enabled = true _gs_anti_semi_join_allowed = true _optim_new_default_join_sel = true optimizer_dynamic_sampling = 2 _pre_rewrite_push_pred = true _optimizer_new_join_card_computation = true _union_rewrite_for_gs = yes_gset_mvs _generalized_pruning_enabled = true _optim_adjust_for_part_skews = true _force_datefold_trunc = false statistics_level = typical _optimizer_system_stats_usage = true skip_unusable_indexes = true _remove_aggr_subquery = true _optimizer_push_down_distinct = 0 _dml_monitoring_enabled = true _optimizer_undo_changes = false _predicate_elimination_enabled = true _nested_loop_fudge = 100 _project_view_columns = true _local_communication_costing_enabled = true _local_communication_ratio = 50 _query_rewrite_vop_cleanup = true _slave_mapping_enabled = true _optimizer_cost_based_transformation = linear _optimizer_mjc_enabled = true _right_outer_hash_enable = true _spr_push_pred_refspr = true _optimizer_cache_stats = false _optimizer_cbqt_factor = 50 _optimizer_squ_bottomup = true _fic_area_size = 131072 _optimizer_skip_scan_enabled = true _optimizer_cost_filter_pred = false _optimizer_sortmerge_join_enabled = true _optimizer_join_sel_sanity_check = true _mmv_query_rewrite_enabled = false _bt_mmv_query_rewrite_enabled = true _add_stale_mv_to_dependency_list = true _distinct_view_unnesting = false _optimizer_dim_subq_join_sel = true _optimizer_disable_strans_sanity_checks = 0 _optimizer_compute_index_stats = true _push_join_union_view2 = true _optimizer_ignore_hints = false _optimizer_random_plan = 0 _query_rewrite_setopgrw_enable = true _optimizer_correct_sq_selectivity = true _disable_function_based_index = false _optimizer_join_order_control = 3 _optimizer_push_pred_cost_based = true flashback_table_rpi = non_fbt _optimizer_cbqt_no_size_restriction = true _optimizer_or_expansion = breadth _optimizer_rownum_pred_based_fkr = true _optimizer_better_inlist_costing = nlonly _optimizer_outer_to_anti_enabled = false *************************************** Column Usage Monitoring is ON: tracking level = 1 *************************************** QUERY BLOCK SIGNATURE ********************* qb name was generated signature (optimizer): qb_name=SEL$1 nbfros=1 flg=0 fro(0): flg=0 objn=197782 hint_alias="COSTEDEVENT"@"SEL$1" *************************************** BASE STATISTICAL INFORMATION *********************** Table stats Table: COSTEDEVENT Alias: COSTEDEVENT (Using composite stats) TOTAL :: CDN: 296160700 NBLKS: 15040307 AVG_ROW_LEN: 261 Index stats Index: COSTEDEVENT_PK COL#: 1 2 3 4 5 USING COMPOSITE STATS TOTAL :: LVLS: 3 #LB: 15040307 #DK: 361175084 LB/K: 1 DB/K: 1 CLUF: 0 Index: COSTEDEVENT_UK1 COL#: 2 5 USING COMPOSITE STATS TOTAL :: LVLS: 3 #LB: 2961679 #DK: 360905528 LB/K: 1 DB/K: 1 CLUF: 20447015 _OPTIMIZER_PERCENT_PARALLEL = 0 *************************************** SINGLE TABLE ACCESS PATH COLUMN: ACCOUNT_NU(VARCHAR2) Col#: 1 Table: COSTEDEVENT Alias: COSTEDEVENT Size: 8 NDV: 47616 Nulls: 0 Density: 2.1001e-05 COLUMN: EVENT_TYPE(NUMBER) Col#: 4 Table: COSTEDEVENT Alias: COSTEDEVENT Size: 2 NDV: 18 Nulls: 0 Density: 5.5556e-02 Min: 1 Max: 29 COLUMN: EVENT_ATTR(VARCHAR2) Col#: 23 Table: COSTEDEVENT Alias: COSTEDEVENT Size: 14 NDV: 1827 Nulls: 402372 Density: 5.4735e-04 COLUMN: EVENT_SEQ(NUMBER) Col#: 2 Table: COSTEDEVENT Alias: COSTEDEVENT Size: 5 NDV: 5 Nulls: 0 Density: 2.0000e-01 Min: 70916001 Max: 71011001 TABLE: COSTEDEVENT Alias: COSTEDEVENT Original Card: 296160700 Rounded: 1 Computed: 0.01 Non Adjusted: 0.01 Access Path: index (index-ffs) Index: COSTEDEVENT_PK rsc_cpu: 107108643882 rsc_io: 2604638 ix_sel: 0.0000e+00 ix_sel_with_filters: 1.0000e+00 Access Path: index-ffs Resc: 2616210 Resp: 2616210 Access Path: index (no start/stop keys) Index: COSTEDEVENT_PK rsc_cpu: 107112578517 rsc_io: 15040859 ix_sel: 1.0000e+00 ix_sel_with_filters: 5.8337e-08 Parallel: resp: 17427 deg: 144 OPTIMIZER PERCENT INDEX CACHING = 100 Access Path: index (index-only) Index: COSTEDEVENT_UK1 rsc_cpu: 1322405301 rsc_io: 0 ix_sel: 9.0000e-03 ix_sel_with_filters: 9.0000e-03 BEST_CST: 22.43 PATH: 4 Degree: 1 *************************************** OPTIMIZER STATISTICS AND COMPUTATIONS *************************************** GENERAL PLANS *********************** Join order[1]: COSTEDEVENT[COSTEDEVENT]#0 Best so far: TABLE#: 0 CST: 22 CDN: 1 BYTES: 261 (newjo-stop-1) k:0, spcnt:0, perm:1, maxperm:80000 Final - All Rows Plan: JOIN ORDER: 1 CST: 22 CDN: 1 RSC: 22 RSP: 22 BYTES: 261 IO-RSC: 1 IO-RSP: 1 CPU-RSC: 198360795 CPU-RSP: 198360795 -- regards ujang -- //www.freelists.org/webpage/oracle-l