History of database monitoring
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History of database monitoring
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History of database monitoring
- 1. Midnight January 28, 1986 Lives are on the line History of Database Monitoring My own experiences http://kylehailey.com Kylelf@gmail.com
- 2. History … 1988 6 1989 1990 1991 1992 7 1993 1994 1995 1996 1997 8 1998 1999 2000 2001 9 2002 2003 10 2005 10.2 2006 2008 200X 2016
- 3. History … 1988 6 1989 Utlbstat/utlestat 1990 joined 1991 1992 7 1993 1994 1995 1996 1997 8 1998 1999 2000 2001 9 2002 2003 10 2005 10.2 2006 2008 200X 2016
- 4. History … 1988 6 1989 Utlbstat/utlestat 1990 joined 1991 1992 7 1993 1994 1995 1996 1997 8 1998 1999 2000 2001 9 2002 2003 10 2005 10.2 2006 2008 200X 2016
- 5. History … 1988 6 1989 Utlbstat/utlestat 1990 joined 1991 1992 7 1993 1994 1995 1996 1997 8 1998 1999 2000 2001 9 2002 2003 10 2005 10.2 2006 2008 200X 2016
- 6. History … 1988 6 1989 Utlbstat/utlestat 1990 joined 1991 1992 7 1993 1994 1995 1996 1997 8 1998 1999 2000 2001 9 2002 2003 10 2005 10.2 2006 2008 200X 2016
- 7. History … 1988 6 1989 Utlbstat/utlestat 1990 joined 1991 1992 7 Waits 1993 Patrol vs M2 1994 1995 1996 1997 8 1998 1999 2000 2001 9 2002 2003 10 2005 10.2 2006 2008 200X 2016 M2
- 8. History … 1988 6 1989 Utlbstat/utlestat 1990 joined 1991 1992 7 Waits Waits 1993 Patrol vs M2 1994 Tcl/Tk Europe Car 1995 Tcl/Tk waits 1996 1997 8 1998 1999 2000 2001 9 2002 2003 10 2005 10.2 2006 2008 200X 2016
- 9. History … 1988 6 1989 Utlbstat/utlestat 1990 joined 1991 1992 7 Waits Waits 1993 Patrol vs M2 1994 Tcl/Tk Europe Car 1995 Tcl/Tk waits 1996 1997 8 1998 1999 2000 2001 9 2002 2003 10 2005 10.2 2006 2008 200X 2016
- 10. History … 1988 6 1989 Utlbstat/utlestat 1990 joined 1991 1992 7 Waits Waits 1993 Patrol vs M2 1994 Tcl/Tk Europe Car 1995 Tcl/Tk waits 1996 1997 8 1998 Statspack 8.1.6 top waits 1999 Spotlight 2000 2001 9 2002 2003 10 2005 10.2 2006 2008 200X 2016
- 11. History … 1988 6 1989 Utlbstat/utlestat 1990 joined 1991 1992 7 Waits Waits 1993 Patrol vs M2 1994 Tcl/Tk Europe Car 1995 Tcl/Tk waits 1996 1997 8 1998 Statspack 8.1.6 top waits 1999 Spotlight 2000 Statspack 9iR2 top events 2001 9 2002 design OEM 10 2003 10 2005 10.2 2006 2008 200X 2016
- 12. History … 1988 6 1989 Utlbstat/utlestat 1990 joined 1991 1992 7 Waits Waits 1993 Patrol vs M2 1994 Tcl/Tk Europe Car 1995 Tcl/Tk waits 1996 1997 8 1998 Statspack 8.1.6 top waits 1999 Spotlight 2000 Statspack 9iR2 top events 2001 9 2002 design OEM 10 2003 10 OEM 10 2005 10.2 Top Activity 2006 2008 200X 2016
- 13. History … 1988 6 1989 Utlbstat/utlestat 1990 joined 1991 1992 7 Waits Waits 1993 Patrol vs M2 1994 Tcl/Tk Europe Car 1995 Tcl/Tk waits 1996 1997 8 1998 Statspack 8.1.6 top waits 1999 Spotlight 2000 Statspack 9iR2 top events 2001 9 2002 design OEM 10 2003 10 OEM 10 2005 10.2 Top Activity 2006 Ashmon 2008 DB Optimizer 200X YaaMs Delphix 2016
- 14. History … 1988 6 1989 Utlbstat/utlestat 1990 joined 1991 1992 7 Waits Waits 1993 Patrol vs M2 1994 Tcl/Tk Europe Car 1995 Tcl/Tk waits 1996 1997 8 1998 Statspack 8.1.6 top waits 1999 Spotlight 2000 Statspack 9iR2 top events 2001 9 2002 design OEM 10 2003 10 OEM 10 2005 10.2 Top Activity 2006 Ashmon 2008 DB Optimizer 200X YaaMs Delphix 2016 Amazon
- 15. Computer Performance 1. Interactive • Opaque: Static, idiosyncrasies Vs • Fun : Graphic , informative 1. Sampling • Counters and ratios Vs • Waits and sampling 1. Graphics • Spaghetti on the wall Vs • Intelligence in the interface
- 16. Computer Performance 1. Interactive • Opaque: Static, idiosyncrasies Vs • Fun : Graphic , informative 1. Sampling • Counters and ratios Vs • Waits and sampling 1. Graphics • Spaghetti on the wall Vs • Intelligence in the interface
- 17. Computer Performance 1. Interactive • Opaque: Static, idiosyncrasies Vs • Fun : Graphic , informative 1. Sampling • Counters and ratios Vs • Waits and sampling 1. Graphics • Spaghetti on the wall Vs • Intelligence in the interface
- 18. Theme: Let’s make performance tuning a video game
- 20. The journey of simplicity: Designing an Interface
- 21. The journey of simplicity 1. Seems simple “When you start looking at a problem and it seems really simple, you don’t really understand the complexity of the problem.” – Steve Jobs
- 22. The journey of simplicity 1. Seems simple 2. Realize it’s complex
- 23. The journey of simplicity 1. Seems simple 2. It’s complex 3. Create complex solution “Then you get into the problem, and you see that it’s really complicated, and you come up with all these convoluted solutions. That’s sort of the middle, and that’s where most people stop.” – Steve Jobs
- 24. The journey of simplicity 1. Seems simple 2. It’s complex 3. Complex solution 4. Complex solution is bad
- 25. The journey of simplicity 1. Seems simple 2. It’s complex 3. Complex solution 4. Complex is bad 5. Simple powerful is hard “But the really great person will keep on going and find the key, the underlying principle of the problem — and come up with an elegant, really beautiful solution that works.” – Steve Jobs
- 26. Simple can be harder than complex. You have to work hard to get your thinking clean to make it simple.
- 27. Prototype & Iterate (Cary Millsap)
- 28. Thought: images are running the world
- 29. Computers (&DBs)- can be “black boxes”
- 30. How do you get in?
- 31. How do you get in?
- 32. Wordstar
- 33. Text Friction
- 34. You log in, then what?
- 35. 1984 OK, UI can change everything
- 38. How do you make good tools ?
- 40. Make it a video game !
- 41. Utlbstat/Utlestat … •Intrusive •Overwhelming •Ratios & Averages rem $Header: utlbstat.sql 26-feb-96.19:20:51 gpongrac Exp Rem Copyright (c) 1988, 1996 by Oracle Corporation Rem NAME REM UTLBSTAT.SQL Rem MODIFIED Rem khailey 03/15/99 - add current user fields to Rem jloaiza 10/14/95 - add tablespace size Rem jloaiza 09/19/95 - add waitstat Rem jloaiza 09/04/95 - add per second and backgro Rem drady 09/09/93 - merge changes from branch Rem drady 03/22/93 - merge changes from branch Rem drady 08/24/93 - bug 173918 Rem drady 03/04/93 - fix bug 152986 Rem glumpkin 11/16/92 - Renamed from UTLSTATB.SQL Rem glumpkin 10/19/92 - Renamed from BSTAT.SQL Rem jloaiza 01/07/92 - rework for version 7 Rem mroberts 08/16/91 - fix view for v7 Rem rlim 04/29/91 - change char to varc Rem Laursen 01/01/91 - V6 to V7 merge Rem Loaiza 04/04/89 - fix run dates to minutes inst Rem Martin 02/22/89 - Creation Rem Jloaiza 02/23/89 - changed table names, added da Rem insert into stats$begin_event select * from v$system_even insert into stats$begin_roll select * from v$rollstat; insert into stats$begin_file select * from stats$file_vie insert into stats$begin_dc select * from v$rowcache; insert into stats$begin_stats select * from v$sysstat; insert into stats$begin_lib select * from v$librarycache; insert into stats$begin_latch select * from v$latch;
- 45. 1993 First Monitors - Patrol
- 46. 1993 Patrol on Dec 8400
- 47. 1993
- 49. Roger Saunders M2 •Light Weight •Direct Memory Access •
- 50. Roger Saunders M2 •Light Weight •Direct Memory Access •Sampling
- 51. 1994 Light weight graphic : Tcl/Tk + M2
- 54. 1995 Monitor Everything Approach
- 57. Wait Events Became the Focus Graphs created dynamically Easy to destroy
- 58. Wait Events Became the Focus Graphs created dynamically Easy to destroy
- 59. Improvements •Scale Graphs Equally Eliminate: •Background waits •Idle Waits •Extraneous waits •Wait counts
- 60. log_file_switch_completion : increase log file size http://oraperf.sourceforge.net/seminar/ex3_test_2.html Centi- seconds
- 61. free buffer waits : increase db_block_buffers
- 62. log file sync : log file -> raw device
- 63. db file sequential read : increase db_block_buffers
- 64. write complete wait free buffer waits : increase db_block_buffers db file sequential reads
- 65. Final
- 66. Tuning catproc.sql on version 7 Compulsive Tuning Disorder Missing CPU usage to put into perspective
- 67. 1998 8.1.6 Statspack •Kyle wanted M2 & Graphics •Connie wanted statspack •boss : neither ! •Connie did statspack •I left
- 68. 1998 8.1.6 Statspack •Kyle wanted M2 & Graphics •Connie wanted statspack •boss : neither ! •Connie did statspack •I left
- 69. 1998 8.1.6 Statspack •Kyle wanted M2 & Graphics •Connie wanted statspack •boss : neither ! •Connie did statspack •I left
- 70. 1998 8.1.6 Statspack •Kyle wanted M2 & Graphics •Connie wanted statspack •boss : neither ! •Connie did statspack •I left •In the mean time ….
- 71. 1
- 72. 2
- 73. 3
- 74. 4
- 75. 5
- 76. 6
- 77. 7
- 78. 8
- 79. 9
- 80. 10
- 81. 11
- 82. 1999 Spotlight
- 83. Without Reading a Manual •Handspring’s site crashed Nov 25, 1999 •Biggest Sales Day of the Year •Library cache latch contention •No DBAs •Downloaded Quest’s Spotlight •Installed and Identified problem with Minutes •Solution in code fix
- 84. Spotlight – Stacked Waits !
- 85. Ratio of waits to CPU • How do you get CPU? • CPU stats? Centi- seconds
- 87. Session count CPU stacked No wait groups
- 88. EM v10 Proposed Perf Page (v4.1)
- 89. Avoid Scrolling and Hiding Data
- 90. OEM
- 91. Sampling vs Counters •Given a wait bottleneck •Which User •Which SQL •What object / file / block •Not feasible with counters •Easy and cheap with Sampling : Multi-dimensional
- 92. Before ASH:Before ASH: • Sessions v$sesstat, v$session_event • # sessions x (# wait events + statistics) • Example (150 x (800+200) = 150,000 ) • SQL v$sql • Could be 10000s • Takes out latches that compete with other sql executions • Objects V$segstat • Could be 1000s of objects • Files v$filestat Expensive !
- 93. Multi-DimensionalMulti-Dimensional Top Consumers Session User Object Module.Action Program Service Client Wait X Top Resources • CPU • Waits • Event (800*) • I/O • File • Block • Time Top SQL SQL ID Plan Child# X And Aggregated over any time Period
- 94. Multi-dimensionalMulti-dimensional 25 34 36 38 45 63 65 8725 34 36 38 45 63 65 87 F1qcyh20550cfF1qcyh20550cf fj6gjgsshtxyxfj6gjgsshtxyx 0cjsxw5ndqdbc0cjsxw5ndqdbc 8t8as9usk11qw8t8as9usk11qw dr1rkrznhh95bdr1rkrznhh95b 10dkqv3kr8xa510dkqv3kr8xa5 38zhkf4jdyff438zhkf4jdyff4 298wmz1kxjs1m298wmz1kxjs1m C PU C PUEnq: TX – row lock contention Enq: TX – row lock contention SQ L*N et break/reset to client SQ L*N et break/reset to client db file scattered read db file scattered read db file sequential read db file sequential read IO Application SQLSQL Sessions W aits W aits ServiceService Scott SystemUserUser ProgramProgram Sys Sqlplus Toad GL OE Package Procedure Plan Child #
- 96. Statistic Lag Time Copyright 2006 Kyle Hailey CountersCounters SamplesSamples Slight LagsSlight Lags
- 97. If you are not tuning for time, you are wasting time Max CPU (yard stick) Top ActivityTop Activity SQLSQL SessionsSessions LOADLOAD
- 99. Confio Ignite
- 100. Dell Foglight
- 101. Lab128
- 102. D.side
- 103. W-ASH
- 104. Ashviewer
- 105. emlite
- 106. ASHmon
- 107. MyOra
- 108. Mumbai
- 109. Precise
- 110. Lighty
- 111. Example Problem How so you communicated quantive data ?
- 112. Midnight January 28, 1986 Lives are on the line Thanks to Edward Tufte Night before the Flight Jan 27,1986
- 114. 13 Pages Faxed
- 115. 13 Pages Faxed 3 different types of names
- 116. Damage (in overwhelming detail) but No Temperatures 13 Pages Faxed
- 117. 13 Pages Faxed Missing Data for 5 erosion damage flights Blow by Damage Test engines fired horizontally
- 118. 13 Pages Faxed Shows “blow by”, not more important “erosion” Damage at hottest and coldest launches * (of the flights shown) Next day’s flight
- 120. 55 65 7560 70 80 1 Original Engineering data 2 3 ““damages atdamages at the hottestthe hottest and coldestand coldest Temperature”Temperature” Would you launch?
- 122. Congressional Hearings Evidence No Damage Legend Damage hard to read
- 124. 55 65 7560 70 80 1 Original Data 2 3
- 125. Clearer 1. Y-Axis amount of damage (not number of damage) 55 65 7560 70 80 4 8 12
- 126. 1. Y-Axis amount of damage (not number of damage) 2. Include successes * 55 65 7560 70 80 4 8 12 Clearer * Only external temperatures were known not the temperature of the solid rocket boosters Be accurate enough
- 127. 1. Y-Axis amount of damage (not number of damage) 2. Include successes 3. Mark Differences 55 65 7560 70 80 4 8 12 Clearer
- 128. 1. Y-Axis amount of damage (not number of damage) 2. Include successes 3. Mark Differences 4. Normalize same temp 55 65 7560 70 80 4 8 12 Clearer
- 129. 1. Y-Axis amount of damage (not number of damage) 2. Include successes 3. Mark Differences 4. Normalize same temp 55 65 7560 70 80 4 8 12 Clearer Damage on every flight below 65 No damage on every flight above 75
- 130. 1. Y-Axis amount of damage (not number of damage) 2. Include successes 3. Mark Differences 4. Normalize same temp 55 65 7560 70 80 4 8 12 Clearer Known World
- 131. 1. Y-Axis amount of damage (not number of damage) 2. Include successes 3. Mark Differences 4. Normalize same temp 5. Scale known vs unknown 55 65 7560 70 80 4 8 12 4 8 12 30 40 5035 45 XX Clearer
- 132. Difficult NASA Engineers Fail Congressional Investigators Fail Data Visualization is Difficult But … Lack of Clarity can be devastating
- 133. Visualization can be powerful
- 134. “If I can't picture it, I can't understand it” Anscombe's Quartet I II III IV x y x y x y x y 10 8.04 10 9.14 10 7.46 8 6.58 8 6.95 8 8.14 8 6.77 8 5.76 13 7.58 13 8.74 13 12.74 8 7.71 9 8.81 9 8.77 9 7.11 8 8.84 11 8.33 11 9.26 11 7.81 8 8.47 14 9.96 14 8.1 14 8.84 8 7.04 6 7.24 6 6.13 6 6.08 8 5.25 4 4.26 4 3.1 4 5.39 19 12.5 12 10.84 12 9.13 12 8.15 8 5.56 7 4.82 7 7.26 7 6.42 8 7.91 5 5.68 5 4.74 5 5.73 8 6.89 Average 9 7.5 9 7.5 9 7.5 9 7.5 Standard Deviation 3.31 2.03 3.31 2.03 3.31 2.03 3.31 2.03 Linear Regression 1.33 1.33 1.33 1.33 - Albert Einstein- Albert Einstein
- 135. Graphics for Anscombe’s Quartet
- 136. Counties in US > 3000 Counties > 50 pages “The humans … are exceptionally good at parsing visual information.” Knowledge representation in cognitive science. Westbury, C. & Wilensky, U. (1998)
- 137. Visualizations can also obfuscate
- 138. Pretty Picture
- 139. Spaghetti at the wall
- 140. Spaghetti at the wall II
- 141. Amazon Cloudwatch
- 142. Imagine Trying to Drive your Car And is updated once and hourAnd is updated once and hour Or would you like it toOr would you like it to look …look … Would you want your dashboard to look like :Would you want your dashboard to look like :
- 143. If you are not tuning for time, you are wasting time
- 144. When Developers sayWhen Developers say The Database is slowThe Database is slow
- 147. AAS ~= 0AAS ~= 0
- 148. Do You Want? Engineering Data?Engineering Data?
- 149. Pretty PicturesPretty Pictures Do You Want?
- 150. Clean and ClearClean and Clear ? ? ? ?? ? ? ? ? ?? ? Do You Want?
- 151. Summary •Textual statistics – difficult to parse •Pretty pictures misleading •Goal clear graphics powerful Kylelf@gmail.com http://kylehailey.com
- 152. Summary •Textual statistics – difficult to parse •Pretty pictures misleading •Goal clear graphics powerful Simple can be harder than complex. You have to work hard to get your thinking clean to make it simple. Prototype & Iterate Kylelf@gmail.com http://kylehailey.com
- 153. •END
Notes de l'éditeur
- Have you ever been hiking in the Sierras ? I went hiking in Yosemite by myself. I was friends with one of the park rangers in Yosemite. She love to hike and she always hiked off trail. She told me about a beautiful lake off trail that would be wonderful to hike to. The lake was just on the other side of the mountain crest from where we were. She gave me a topographic map to use. Have you ever used a topographic map? It’s a map that shows elevations with contour lines. Each line denotes say 50’ of elevation change. The more lines together closer together the steeper the terrain. I used this map to plot out a course to the lake that didn’t have cliffs or other obstacles. I managed to make it to the top of the mountain crest and when there I could see the beautiful lake below way off any trail. From where I was it was a steep descent of 300 feet to the lake. All approaches looked the same on the topographic map. As I approached the lake it got steeper and steeper and steeper. I finally found my self on a vertial face with no way to go down father And unsure if I could even climb back up. I was stuck. Then I thought “if I got here with a big back pack on, I can certainly climb back up without it!” I gingerly undid the clips and slid my backpack off my back. Swoosh It went down the rock face. Unbeknownst to me, there was a snow ramp at the bottom of the clift left over from the winter. My pack hit the snow ramp at full force and went shooting out into the middle of the lake. Here I was like at 8pm at on a late summer’s dusk in the mountains at 11’000 feet way off train after a day of hiking and my backpack with my foot, shelter, warm clothing was in the middle of a lake 100-200 feet below. Lucky for me my backpack floated and before long had floated to the side of the lake. I went back up tried a different path down and made it. But it just goes to show that the user interface of this particular topographic map didn’t distinguish between an impenetrable 200 feet and a navigat-able 200 feet drop. Hi, my names Kyle Hailey, and I love working with user interface s that help me navigate the world.
- I was taking the bus last week and looked around In the row in front of me every one of was on the phones All of those people on their phones where on photo sights like Instagram It’s amazing how online experience is moving towards photos and images I noticed a couple of years a go on Facebook how quotes overlaid on a photo Would be shard many more times than just text quotes
- A computer or a program or a database can be challenging to get started with
- The MacIntosh came out in 1984 1984 was the year I went to college And my school Cornell got bunches of them for the computer labs It was great I just sat down without a manual for the frist time and I was able to work Mind blowing after starting on a teletype computer 2 years earlier
- The monitor of Roger Saunders has been around since 1991. See Roger's page The idea to add a graphic interface came up while working at the Perot/Europecar site in 1993. At the time I think it was the largest UNIX site in terms of users with 1500-3000 concurrent users. Europecar was also one of the first production UNIX sites on parallel server having 3 nodes with 1.5 Gig RAM and 12 cpus each. At the time that was pretty impressive. At the site was a support person from Sequent, Jan Simon Pendry. He basically rewrote the Perot/Europecar benchmark not previous knowing Oracle. The rewrite used proc that could be generated off Oracle trace files. He also corrected Sequent UNIX kernel bugs and handle basic Sequent support. In between all those tasks he put together a graphic monitor in a week for Oracle using tcl/tk. I had never heard of tcl/tk but I was impressed and kept the idea in the back of my mind. I talked to various people over the next two years saying wouldn't it be neat to put a graphic monitor together (especially with Rogers monitor as the base). I never had time myself because of doing phone support and no one else took the baton. Then in the fall of 1995 I started spending about 2 weeks a month at Digital Europe benchmarking. Of course the benchmarks never allocated enough time and time became an enviable commodity. The big problem with tuning was finding the problems fast and easily. Lots of people have put sqlpackages together basically being more efficeint forms of bstat/estat. The problem at that point became trying to anaylze all the output. This is fine when I have the time and when I know about the application, but in the benchmarks often the client was not even there so I had no idea what the application did, and time was essential, because there was never enough. It was at that point that I decided to put the graphic interface together myself. I have been quite happy with the monitor at bench marks, but not being a 'real' programmer myself maybe someone can see what the idea is and take it farther.
- The monitor of Roger Saunders has been around since 1991. See Roger's page The idea to add a graphic interface came up while working at the Perot/Europecar site in 1993. At the time I think it was the largest UNIX site in terms of users with 1500-3000 concurrent users. Europecar was also one of the first production UNIX sites on parallel server having 3 nodes with 1.5 Gig RAM and 12 cpus each. At the time that was pretty impressive. At the site was a support person from Sequent, Jan Simon Pendry. He basically rewrote the Perot/Europecar benchmark not previous knowing Oracle. The rewrite used proc that could be generated off Oracle trace files. He also corrected Sequent UNIX kernel bugs and handle basic Sequent support. In between all those tasks he put together a graphic monitor in a week for Oracle using tcl/tk. I had never heard of tcl/tk but I was impressed and kept the idea in the back of my mind. I talked to various people over the next two years saying wouldn't it be neat to put a graphic monitor together (especially with Rogers monitor as the base). I never had time myself because of doing phone support and no one else took the baton. Then in the fall of 1995 I started spending about 2 weeks a month at Digital Europe benchmarking. Of course the benchmarks never allocated enough time and time became an enviable commodity. The big problem with tuning was finding the problems fast and easily. Lots of people have put sqlpackages together basically being more efficeint forms of bstat/estat. The problem at that point became trying to anaylze all the output. This is fine when I have the time and when I know about the application, but in the benchmarks often the client was not even there so I had no idea what the application did, and time was essential, because there was never enough. It was at that point that I decided to put the graphic interface together myself. I have been quite happy with the monitor at bench marks, but not being a 'real' programmer myself maybe someone can see what the idea is and take it farther.
- Graphs had different scales, hard to compare values in one graph to another. Different scale was fine for v$sysstat where statistics were unrelated or orders of magnitude different in scale. Waits on the other hand were all measured in the same units (centi-seconds). It was natural to make all graphs have the same scale on the axis. Background waits – unnecessary to display Idle Waits – unnecessary to display Extraneous waits, too many graphs. Each new wait was a new graph and the amount of graphs could be staggering. I ended up implementing a double click command that would kill any unwanted graphs ( sort of like a video game point and shoot) Didn’t need counts, ie the frequency of waits, and concentrated on the amount of time waited.
- Fast install Moving parts – even when not connected Non-Oracle Experts could use it
- The software was written in Perl. They used a random number generator to generate random order numbers. Once a random number between 1 and 100,000,000 had been generated then the order number was looked up in the database to see if it existed before being used. This had its own problems such as duplicate keys because of the non atomic nature of the operation, but the fatal blow came from a perl bug that actually only created 15,000 unique numbers in the requested number space of 1 to 100,000,000. Once the 15,000th order was hit, then every usersn spent their time generating order numbers and looking them up in the database. Since these queries weren’t using bind variables there was severe contention on the library cache latch, but the real problem wasn’t bind variables, it was the flaw in the application code. Spotlight pointed this out clearly and quickly to a group of coders and system administrators who had no Oracle experience.
- The bulk of the presentaiton is on ideas presented by Edward Tufte in his books But I will also tie in breifly one industry example (or more if I go too fast)
- The O-rings of the solid rocket boosers were not designed to erode. Erosion was a clue that something was wrong. Erosion was not something from which safety could be inferred - Richard Feynman
- The O-rings of the solid rocket boosers were not designed to erode. Erosion was a clue that something was wrong. Erosion was not something from which safety could be inferred - Richard Feynman