Oracle Database Performance Tuning, Benchmarks & Replication

Transcription

1 Oracle Database Performance Tuning, Benchmarks & Replication Kapil Malhotra Solutions Architect, Information Management Dell Software

2 2 11/29/2013 Software

3 Database Tuning Database Tuning is a set of activities performed to optimize the performance of a database Goal To make the following database tasks run efficiently with optimal usage of system resources: Pl/SQL code (PL/SQL blocks, functions, procedures, triggers etc) SQL queries (Select, Insert, Update, Deletes) 3 11/29/2013 Software

4 Database Tuning?? 4 11/29/2013 Software

5 When I should consider Tuning Resource I/O Bottlenecks Bad SQLs (FTS, Long Range Scans, Sorts) Disk layout (LUN carving, Data files stripping and distribution) CPU usage Inefficient application logic Bad SQLs Memory Management SGA sizing PGA sizing Workload Latch Contention Shared Pool / Buffer Cache 5 11/29/2013 Software

6 Instance Tuning (Database) Memory Wait Events (Buffer waits, Shared Pool / Library Cache waits) Buffer hit ratios and usage Auto Memory Management I/O Row Chaining Data and Index Fragmentation Data files and Disk Layouts Extent Management (initial, next, pctincrease) and ASSM (initrans, pctfree, freelist etc) Data Model (ER Diagram) Normalization and selective Denormalization Query Rewrite 6 11/29/2013 Software

7 SQL Tuning (Application) Optimizer Statistics (CBO) Missing or Stale Statistics CPU / system Statistics Skewed Data (Column Histograms) dbms_stats.gather_<>_stat (AUTO) Application Code Predicates construction (Access Vs Filter) in SQL queries Bind Variable usage and Bind Peeking View Merging (Complex) and Push Predicate 7 11/29/2013 Software

8 Predicates (Access and Filter) explain plan for UPDATE RA_INTERFACE_LINES L1 SET REQUEST_ID = :b1, LAST_UPDATE_DATE = sysdate, LAST_UPDATED_BY = :b2, LAST_UPDATE_LOGIN = :b3, CUSTOMER_TRX_ID = NULL, INTERFACE_LINE_ID = NVL(INTERFACE_LINE_ID,RA_CUSTOMER_TRX_LINES_S.NEXTVAL), SET_OF_BOOKS_ID = NVL(SET_OF_BOOKS_ID, :b4), LINK_TO_LINE_ID = (SELECT INTERFACE_LINE_ID FROM RA_INTERFACE_LINES L2 WHERE L2.REQUEST_ID = :b5 AND L2.INTERFACE_LINE_CONTEXT = 'DEBIT MEMO' AND L1.LINK_TO_LINE_CONTEXT = L2.INTERFACE_LINE_CONTEXT AND L1.LINK_TO_LINE_ATTRIBUTE1 = L2.INTERFACE_LINE_ATTRIBUTE1 AND L1.LINK_TO_LINE_ATTRIBUTE2 = L2.INTERFACE_LINE_ATTRIBUTE2 ) WHERE NVL(INTERFACE_STATUS, '~')!= 'P' AND (REQUEST_ID IS NULL) AND (LINK_TO_LINE_CONTEXT,LINK_TO_LINE_ATTRIBUTE1,LINK_TO_LINE_ATTRIBUTE2) IN (SELECT /*+ cardinality(l2 10) */ L2.INTERFACE_LINE_CONTEXT,L2.INTERFACE_LINE_ATTRIBUTE1,L2.INTERFACE_LINE_ATTRIBUTE2 FROM RA_INTERFACE_LINES L2 WHERE L2.REQUEST_ID = :b6 AND L2.INTERFACE_LINE_CONTEXT = 'DEBIT MEMO' ); Explained. 8 11/29/2013 Software

9 Plan hash value: Id Operation Name Rows Bytes Cost (%CPU) Time UPDATE STATEMENT (0) 1 UPDATE RA_INTERFACE_LINES_ALL 2 SEQUENCE RA_CUSTOMER_TRX_LINES_S * 3 FILTER 4 NESTED LOOPS SEMI (10) 00:00:01 * 5 TABLE ACCESS FULL RA_INTERFACE_LINES_ALL (9) 00:00:01 * 6 TABLE ACCESS BY INDEX ROWID RA_INTERFACE_LINES_ALL (46) 00:00:01 * 7 INDEX RANGE SCAN RA_INTERFACE_LINES_N (0) 00:00:01 * 8 FILTER * 9 TABLE ACCESS BY INDEX ROWID RA_INTERFACE_LINES_ALL (54) 00:00:01 * 10 INDEX RANGE SCAN RA_INTERFACE_LINES_N (12) 00:00: Predicate Information (identified by operation id): filter(null IS NOT NULL) 5 - filter("request_id" IS NULL AND "LINK_TO_LINE_ATTRIBUTE1" IS NOT NULL AND "LINK_TO_LINE_ATTRIBUTE2" IS NOT NULL AND "LINK_TO_LINE_CONTEXT"='DEBIT MEMO' AND NVL("INTERFACE_STATUS",'~')<>'P') 6 - filter("interface_line_context"='debit MEMO' AND "INTERFACE_LINE_ATTRIBUTE2" IS NOT NULL AND "LINK_TO_LINE_CONTEXT"="INTERFACE_LINE_CONTEXT" AND "LINK_TO_LINE_ATTRIBUTE1"="INTERFACE_LINE_ATTRIBUTE1" AND "LINK_TO_LINE_ATTRIBUTE2"="INTERFACE_LINE_ATTRIBUTE2") 7 - access("request_id"=to_number(:b6)) 8 - filter(null IS NOT NULL AND 'DEBIT MEMO'=:B1) 9 - filter("interface_line_attribute1"=:b1 AND "INTERFACE_LINE_ATTRIBUTE2"=:B2 AND "INTERFACE_LINE_CONTEXT"='DEBIT MEMO') 10 - access("request_id"=to_number(:b5)) 9 11/29/2013 Software

10 Plan hash value: Id Operation Name Rows Bytes Cost (%CPU) Time UPDATE STATEMENT (0) 1 UPDATE RA_INTERFACE_LINES_ALL 2 SEQUENCE RA_CUSTOMER_TRX_LINES_S * 3 FILTER 4 NESTED LOOPS SEMI (9) 00:00:01 * 5 TABLE ACCESS FULL RA_INTERFACE_LINES_ALL (9) 00:00:01 * 6 TABLE ACCESS BY INDEX ROWID RA_INTERFACE_LINES_ALL (0) 00:00:01 * 7 INDEX RANGE SCAN RA_INTERFACE_LINES_N1 1 1 (0) 00:00:01 * 8 FILTER * 9 TABLE ACCESS BY INDEX ROWID RA_INTERFACE_LINES_ALL (0) 00:00:01 * 10 INDEX RANGE SCAN RA_INTERFACE_LINES_N1 2 1 (0) 00:00: Predicate Information (identified by operation id): filter(null IS NOT NULL) 5 - filter("request_id" IS NULL AND "LINK_TO_LINE_ATTRIBUTE1" IS NOT NULL AND "LINK_TO_LINE_ATTRIBUTE2" IS NOT NULL AND "LINK_TO_LINE_CONTEXT"='DEBIT MEMO' AND NVL("INTERFACE_STATUS",'~')<>'P') 6 - filter("request_id"=to_number(:b6)) 7 - access("interface_line_context"='debit MEMO' AND "LINK_TO_LINE_ATTRIBUTE1"="INTERFACE_LINE_ATTRIBUTE1" AND "LINK_TO_LINE_ATTRIBUTE2"="INTERFACE_LINE_ATTRIBUTE2") filter("interface_line_attribute2" IS NOT NULL AND "LINK_TO_LINE_CONTEXT"="INTERFACE_LINE_CONTEXT") 8 - filter(null IS NOT NULL AND 'DEBIT MEMO'=:B1) 9 - filter("request_id"=to_number(:b5)) 10 - access("interface_line_context"='debit MEMO' AND "INTERFACE_LINE_ATTRIBUTE1"=:B1 AND 10 11/29/2013 "INTERFACE_LINE_ATTRIBUTE2"=:B2) Software

11 Bind Variables Usage and Bind Peeking declare v_val1 VARCHAR2(1000); p_job VARCHAR2 (10); p_number NUMBER; BEGIN p_job := DBA ; v_val1 := insert into kapil select * from emp where job = p_job '; EXECUTE IMMEDIATE v_val1 ; End; declare v_val1 VARCHAR2(1000); p_job VARCHAR2 (10); p_number NUMBER; BEGIN p_job := DBA ; v_val1 := ' insert into kapil select * from emp where job = :bind_job'; EXECUTE IMMEDIATE v_val1 USING p_job; End; 11 11/29/2013 Software

12 View Merging and Push Predicates Simple View Merging Source: docs.oracle.com (E ) SELECT e.first_name, e.last_name, dept_locs_v.street_address, dept_locs_v.postal_code FROM employees e, (SELECT d.department_id, d.department_name, l.street_address, l.postal_code FROM departments d, locations l WHERE d.location_id = l.location_id ) dept_locs_v WHERE dept_locs_v.department_id = e.department_id AND e.last_name = 'Smith'; Without View Merging Id Operation Name Cost (%CPU) SELECT STATEMENT 7 (15) * 1 HASH JOIN 7 (15) 2 TABLE ACCESS BY INDEX ROWID EMPLOYEES 2 (0) * 3 INDEX RANGE SCAN EMP_NAME_IX 1 (0) 4 VIEW 5 (20) * 5 HASH JOIN 5 (20) 6 TABLE ACCESS FULL LOCATIONS 2 (0) 7 TABLE ACCESS FULL DEPARTMENTS 2 (0) 12 11/29/ Software

13 View Merging and Push Predicates Simple View Merging Source: docs.oracle.com (E ) SELECT e.first_name, e.last_name, l.street_address, l.postal_code FROM employees e, departments d, locations l WHERE d.location_id = l.location_id AND d.department_id = e.department_id AND e.last_name = 'Smith'; With View Merging Id Operation Name Cost (%CPU) SELECT STATEMENT 4 (0) 1 NESTED LOOPS 2 NESTED LOOPS 4 (0) 3 NESTED LOOPS 3 (0) 4 TABLE ACCESS BY INDEX ROWID EMPLOYEES 2 (0) * 5 INDEX RANGE SCAN EMP_NAME_IX 1 (0) 6 TABLE ACCESS BY INDEX ROWID DEPARTMENTS 1 (0) * 7 INDEX UNIQUE SCAN DEPT_ID_PK 0 (0) * 8 INDEX UNIQUE SCAN LOC_ID_PK 0 (0) 9 TABLE ACCESS BY INDEX ROWID LOCATIONS 1 (0) /29/2013 Software

14 View Merging and Push Predicates Simple View Merging Source: docs.oracle.com (E ) Where it does not work The view contains constructs not included in select-project-join views, including: GROUP BY DISTINCT Outer join MODEL CONNECT BY Set operators Aggregation The view appears on the right side of a semijoin or antijoin. The view contains subqueries in the SELECT list. The outer query block contains PL/SQL functions. The view participates in an outer join, and does not meet one of the several additional validity requirements that determine whether the view can be merged /29/2013 Software

15 View Merging and Push Predicates Complex View Merging Source: docs.oracle.com (E ) Merging of views that involve GROUP BY and DISTINCT clauses Push Predicates If View Merging is not possible Optimizer goes for Push Predicates Denoted by VIEW PUSH PREDICATE OR VIEW UNION ALL PUSH PREDICATE 15 11/29/2013 Software

16 Utilities for PT Explain Plan (Plan Table and V$SQL_PLAN) Oracle Hints SQL Profiling and Events System Statistics Views (v$sysstat, v$sesstat) Reports (Statspack, AWR/ASH/ADDM (Add-on)) 16 11/29/2013 Software

17 Online Reports on OLTP database Why my reports take more time even with no change in explain plan and data volume System Resource Utilization Workload Latch (Cache Buffer Chain) Delayed Block Clean-out 17 11/29/2013 Software

18 Delayed Block Cleanout A Copy of data block to enforce Oracle Read consistency Example of Deferred (Delayed) Block Cleanout 1) Block Dump of a table (alter system dump datafile 1 block 63882; Block header dump: 0x0040f7ba Object id on Block? Y seg/obj: 0xd540 csc: 0x00.ba649 itc: 3 flg: - typ: 1 - DATA fsl: 0 fnx: 0x0 ver: 0x01 Itl Xid Uba Flag Lck Scn/Fsc 0x01 0xffff x C--- 0 scn 0x ba649 0x02 0x x fsc 0x data_block_dump,data header at 0x82f /29/2013 Software

19 Delayed Block Cleanout 2) Issue a DML transaction on the table (Update on table and no commit) Block header dump: 0x0040f7ba Object id on Block? Y seg/obj: 0xd540 csc: 0x00.ba649 itc: 3 flg: - typ: 1 - DATA fsl: 0 fnx: 0x0 ver: 0x01 Itl Xid Uba Flag Lck Scn/Fsc 0x01 0xffff x C--- 0 scn 0x ba649 0x02 0x be 0x00800ba0.00ed fsc 0x data_block_dump,data header at 0x82f /29/2013 Software

20 Delayed Block Cleanout 3) Flush Buffer Cache / Checkpoint and then Commit the DML Transaction Block header dump: 0x0040f7ba Object id on Block? Y seg/obj: 0xd540 csc: 0x00.ba649 itc: 3 flg: - typ: 1 - DATA fsl: 0 fnx: 0x0 ver: 0x01 Itl Xid Uba Flag Lck Scn/Fsc 0x01 0xffff x C--- 0 scn 0x ba649 0x02 0x be 0x00800ba0.00ed fsc 0x data_block_dump,data header at 0x82f /29/2013 Software

21 Delayed Block Cleanout 4) After Select on the table (Select statement also ended up generating redo) Block header dump: 0x0040f7ba Object id on Block? Y seg/obj: 0xd540 csc: 0x00.ba763 itc: 3 flg: - typ: 1 - DATA fsl: 0 fnx: 0x0 ver: 0x01 Itl Xid Uba Flag Lck Scn/Fsc 0x01 0xffff x C--- 0 scn 0x ba649 0x02 0x be 0x00800ba0.00ed.22 C--- 0 scn 0x ba732 data_block_dump,data header at 0x82f /29/2013 Software

22 Report Offloading Report Offloading Materialize Views (Fast and Complete Refreshable) Change Data Capture Using Triggers Using Online Redo Logs / Archive Logs 22 11/29/2013 Software

23 What is Benchmarking Wikipedia Benchmarking is used to measure performance using a specific indicator ([transactions per second, transactional latency, etc]) resulting in a metric of performance that is then compared to others. My Interpretation Simulate running production load while taking many measurements; rerun with changes; and compare 23 11/29/2013 Software

24 Why Benchmark Planned and unplanned changes can have a significant impact on database performance. Examples include: Database patches and upgrades Hardware & Software upgrades OS Migrations (e.g. Windows -> Linux) Physical Machine -> Virtual Machine VM configuration changes The best way to accurately anticipate and measure the affects of these changes is for DBAs to capture workload from a source database and replay on a target, such as test and production /29/2013 Software

25 The Solution How the problem can be solved today? Roll the dice and hope for the best Run systems in parallel and Replicate the database (old=master and new=slave) Manually duplicate application workload Duplicate just the batch portion of the application workload Test using industry standard benchmarks (i.e. TPC-C, TPC-H, etc.) Choose the benchmark(s) closest in nature to your type of system Workload Capture & Replay Probably only reliable testing method 25 11/29/2013 Software

26 Performance Tuning, Benchmarking and Replication solutions by Dell Software Performance Tuning Performance Analysis for Oracle SQL Optimizer for Oracle Benchmarking Benchmark Factory for Oracle Replication SharePlex for Oracle 26 11/29/2013 Software

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