Mark Gurry is owner and President of Mark Gurry & Associates, a 50 person consulting company that provides end-to-end IT services, including 24 x 7 database administration, Web, GUI and back-end development, advice on architecture, business analysis, and design. The Company's performance skills are known worldwide. Mark's and his consultants' short-term site audits, tuning expertise, and internal skills transfer are keenly sought after, and Mark Gurry & Associates is often classified as being the Company to seek out when "only the absolute best will do". Mark Gurry & Associates is headquartered in Australia, and has recently expanded to Seattle in the United States. The Company also has several clients in the UK, New Zealand, and in Asia. Mark's customers are in many areas, including electricity; legal; the stock market; banking and finance; telecommunications; emergency services; and local, state, and federal governments.

• The SQL optimizers - understanding the rule-based optimizer, understanding the cost-based optimizer, some common optimizer misconceptions, which optimizer to use?; rule-based optimizer problems and solutions - problem 1 - incorrect driving table, problem 2 - incorrect index, problem 3 - incorrect driving index, problem 4 - using the ORDER BY index and not the WHERE index; cost-based optimizer problems and solutions - problem 1 - the skewness problem, problem 2 - analyzing with wrong data, problem 3 - mixing the optimizers in joins, problem 4 - choosing an inferior index, problem 5 - joining too many tables, problem 6 - incorrect INIT.ORA parameter settings; problems common to rule and cost with solutions - problem 1 - statement not written for indexes, problem 2 - indexes are missing or inappropriate, problem 3 - use of single-column index merge, problem 4 - misuse of nested loop, sort merge, or hash join, problem 5 - misuse of IN, EXISTS, NOT IN, NOT EXISTS, or table joins, problem 6 - unnecessary sorts, problem 7 - too many indexes on a table, problem 8 - use of OR instead of UNION, problem 9 - tables and indexes with many deletes, other problems - heavy usage of views, other problems - joining too many tables; handy SQL tuning tips - identify bad SQL, identify long-running SQL statements, use DECODE for IF/ELSE selection, encourage bind variables; using SQL hints - when are hints ignored?, using hints in views, available hints; using DBMS_STATS to manage statistics - using DBMS_STATS to analyze faster copying statistics, using dBMS_STATS Manipulating statistics using DBMS_STATS, reverting to previous statistics; using outlines for consistent execution plans - recording outlines, enabling outlines, managing outlines.

Mark Gurry is owner and President of Mark Gurry & Associates, a 50 person consulting company that provides end-to-end IT services, including 24 x 7 database administration, Web, GUI and back-end development, advice on architecture, business analysis, and design. The Company's performance skills are known worldwide. Mark's and his consultants' short-term site audits, tuning expertise, and internal skills transfer are keenly sought after, and Mark Gurry & Associates is often classified as being the Company to seek out when "only the absolute best will do". Mark Gurry & Associates is headquartered in Australia, and has recently expanded to Seattle in the United States. The Company also has several clients in the UK, New Zealand, and in Asia. Mark's customers are in many areas, including electricity; legal; the stock market; banking and finance; telecommunications; emergency services; and local, state, and federal governments.

• The SQL optimizers - understanding the rule-based optimizer, understanding the cost-based optimizer, some common optimizer misconceptions, which optimizer to use?; rule-based optimizer problems and solutions - problem 1 - incorrect driving table, problem 2 - incorrect index, problem 3 - incorrect driving index, problem 4 - using the ORDER BY index and not the WHERE index; cost-based optimizer problems and solutions - problem 1 - the skewness problem, problem 2 - analyzing with wrong data, problem 3 - mixing the optimizers in joins, problem 4 - choosing an inferior index, problem 5 - joining too many tables, problem 6 - incorrect INIT.ORA parameter settings; problems common to rule and cost with solutions - problem 1 - statement not written for indexes, problem 2 - indexes are missing or inappropriate, problem 3 - use of single-column index merge, problem 4 - misuse of nested loop, sort merge, or hash join, problem 5 - misuse of IN, EXISTS, NOT IN, NOT EXISTS, or table joins, problem 6 - unnecessary sorts, problem 7 - too many indexes on a table, problem 8 - use of OR instead of UNION, problem 9 - tables and indexes with many deletes, other problems - heavy usage of views, other problems - joining too many tables; handy SQL tuning tips - identify bad SQL, identify long-running SQL statements, use DECODE for IF/ELSE selection, encourage bind variables; using SQL hints - when are hints ignored?, using hints in views, available hints; using DBMS_STATS to manage statistics - using DBMS_STATS to analyze faster copying statistics, using dBMS_STATS Manipulating statistics using DBMS_STATS, reverting to previous statistics; using outlines for consistent execution plans - recording outlines, enabling outlines, managing outlines.

Mark Gurry is owner and President of Mark Gurry & Associates, a 50 person consulting company that provides end-to-end IT services, including 24 x 7 database administration, Web, GUI and back-end development, advice on architecture, business analysis, and design. The Company's performance skills are known worldwide. Mark's and his consultants' short-term site audits, tuning expertise, and internal skills transfer are keenly sought after, and Mark Gurry & Associates is often classified as being the Company to seek out when "only the absolute best will do". Mark Gurry & Associates is headquartered in Australia, and has recently expanded to Seattle in the United States. The Company also has several clients in the UK, New Zealand, and in Asia. Mark's customers are in many areas, including electricity; legal; the stock market; banking and finance; telecommunications; emergency services; and local, state, and federal governments.

• The SQL optimizers - understanding the rule-based optimizer, understanding the cost-based optimizer, some common optimizer misconceptions, which optimizer to use?; rule-based optimizer problems and solutions - problem 1 - incorrect driving table, problem 2 - incorrect index, problem 3 - incorrect driving index, problem 4 - using the ORDER BY index and not the WHERE index; cost-based optimizer problems and solutions - problem 1 - the skewness problem, problem 2 - analyzing with wrong data, problem 3 - mixing the optimizers in joins, problem 4 - choosing an inferior index, problem 5 - joining too many tables, problem 6 - incorrect INIT.ORA parameter settings; problems common to rule and cost with solutions - problem 1 - statement not written for indexes, problem 2 - indexes are missing or inappropriate, problem 3 - use of single-column index merge, problem 4 - misuse of nested loop, sort merge, or hash join, problem 5 - misuse of IN, EXISTS, NOT IN, NOT EXISTS, or table joins, problem 6 - unnecessary sorts, problem 7 - too many indexes on a table, problem 8 - use of OR instead of UNION, problem 9 - tables and indexes with many deletes, other problems - heavy usage of views, other problems - joining too many tables; handy SQL tuning tips - identify bad SQL, identify long-running SQL statements, use DECODE for IF/ELSE selection, encourage bind variables; using SQL hints - when are hints ignored?, using hints in views, available hints; using DBMS_STATS to manage statistics - using DBMS_STATS to analyze faster copying statistics, using dBMS_STATS Manipulating statistics using DBMS_STATS, reverting to previous statistics; using outlines for consistent execution plans - recording outlines, enabling outlines, managing outlines.