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Why I Hate Django

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    Why I Hate Django - Presentation Transcript

    1. Why I Hate Django Cal Henderson
    2. O HAI DjangoCon 2008 2
    3. My happy face DjangoCon 2008 3
    4. DjangoCon 2008 4
    5. 2.8 billion photos DjangoCon 2008 5
    6. 2.8 billion photos 1 per 2.3 people on earth 9.2 per US resident DjangoCon 2008 6
    7. 35k photos/sec >2m photos/min DjangoCon 2008 7
    8. Many thousand pages/sec DjangoCon 2008 8
    9. Scale nerd DjangoCon 2008 9
    10. Serious Language DjangoCon 2008 10
    11. Wordpress Yahoo Mediawiki Facebook DjangoCon 2008 11
    12. Wordpress Yahoo Delicious Digg Mediawiki Facebook DjangoCon 2008 12
    13. Flamework Serious Toolset DjangoCon 2008 13
    14. Flamework Flink Flint Flotos Flinderbox Flictionary Flaux Flops Flag Fleng DjangoCon 2008 14
    15. Why hate Django? DjangoCon 2008 15
    16. What does he even know about Django? DjangoCon 2008 16
    17. Pownce DjangoCon 2008 17
    18. A fucking blogging engine DjangoCon 2008 18
    19. Why all the hate? DjangoCon 2008 19
    20. DjangoCon 2008 20
    21. DjangoCon 2008 21
    22. DjangoCon 2008 22
    23. DjangoCon 2008 23
    24. An attack on several fronts DjangoCon 2008 24
    25. An attack on several fronts The team Python Frameworks DjangoCon 2008 25
    26. Django itself Performance Scalability Maintainability DjangoCon 2008 26
    27. The Team DjangoCon 2008 27
    28. Frameworks DjangoCon 2008 28
    29. Struts DjangoCon 2008 29
    30. Craig McClanahan DjangoCon 2008 30
    31. DjangoCon 2008 31
    32. Exhibit A : Beard DjangoCon 2008 32
    33. But Struts is for suits! DjangoCon 2008 33
    34. The Hot Shit DjangoCon 2008 34
    35. DjangoCon 2008 35
    36. Rails = Badass DjangoCon 2008 36
    37. Instead? A boy band? DjangoCon 2008 37
    38. DjangoCore The Album DjangoCon 2008 38
    39. DjangoCon 2008 39
    40. Also, a wizard Simon “Stinky” Willison DjangoCon 2008 40
    41. Python DjangoCon 2008 41
    42. Trendy Google! DjangoCon 2008 42
    43. But not that trendy DjangoCon 2008 43
    44. But not that trendy It’s no ruby DjangoCon 2008 44
    45. But not that trendy It’s no ruby Or Haskell DjangoCon 2008 45
    46. But not that trendy It’s no ruby Or Haskell Or Erlang DjangoCon 2008 46
    47. But not that trendy It’s no ruby Or Haskell Or Erlang Or Scala DjangoCon 2008 47
    48. Significant Whitespace DjangoCon 2008 48
    49. DjangoCon 2008 49
    50. Salmon DjangoCon 2008 50
    51. Universe of marshy force. Field sense shallows the hatchery saying Hello,. World!. Hydro. Power spring sometimes; snowmelt powers snowmelt always. DjangoCon 2008 51
    52. DjangoCon 2008 52
    53. No quantum superpositions DjangoCon 2008 53
    54. DjangoCon 2008 54
    55. “-”.join(array) DjangoCon 2008 55
    56. Restarting the server? WTF!? DjangoCon 2008 56
    57. WSGIReloadMechanism DjangoCon 2008 57
    58. “I buy my eggs at the cheese shop” - Aaron Straup Cope DjangoCon 2008 58
    59. “I buy my eggs at the cheese shop” ] - Aaron Straup Cope E G A U G N A L N O O [M DjangoCon 2008 59
    60. DjangoCon 2008 60
    61. __import__() from future import awesome DjangoCon 2008 61
    62. Basically, for hippies Scared of real OO languages DjangoCon 2008 62
    63. Frameworks DjangoCon 2008 63
    64. Flamework is a framework But what does that mean? DjangoCon 2008 64
    65. Make common tasks: easier faster error-free DjangoCon 2008 65
    66. Show a list of photos Write an API method Kill all humans DjangoCon 2008 66
    67. Front-tier frameworks Act as glue DjangoCon 2008 67
    68. Other Data store Services Data Model Business Logic Request Interaction Templates Dispatcher Logic Framework Users DjangoCon 2008 68
    69. Great for getting started Slows you down later? What is it doing in there? DjangoCon 2008 69
    70. DjangoCon 2008 70
    71. DjangoCon 2008 71
    72. DjangoCon 2008 72
    73. Fast Easy Scalable Flexible DjangoCon 2008 73
    74. Large scale is often not a good goal DjangoCon 2008 74
    75. Skyscrapers are special DjangoCon 2008 75
    76. Regular houses Don’t need 10 story foundations DjangoCon 2008 76
    77. Just build! DjangoCon 2008 77
    78. DjangoCon 2008 78
    79. DjangoCon 2008 79
    80. DjangoCon 2008 80
    81. Everything here is possible! We care about easy DjangoCon 2008 81
    82. Large Scale DjangoCon 2008 82
    83. No multiple DB clusters DjangoCon 2008 83
    84. Manual partitioning DjangoCon 2008 84
    85. No multiple hosts per DB DjangoCon 2008 85
    86. Where do we read from? DjangoCon 2008 86
    87. How about now? DjangoCon 2008 87
    88. How about now ? DjangoCon 2008 88
    89. Read/write consistency DjangoCon 2008 89
    90. Read/write consistency LAG!!1 DjangoCon 2008 90
    91. Good for non-writing users (logged out) DjangoCon 2008 91
    92. Non time-sensitive data Feeds Read-only APIs DjangoCon 2008 92
    93. DjangoCon 2008 93
    94. Cool kids use master/master pairs DjangoCon 2008 94
    95. Consistent read/write 1. Write to side A 2. Read from side B 3. Replication occurs 4. FAIL DjangoCon 2008 95
    96. Consistent read/write 1. Write to side A 2. Read from side A 3. ??? 4. PROFIT!! DjangoCon 2008 96
    97. Then we can start to get fancy! DjangoCon 2008 97
    98. Where do we read/write? DjangoCon 2008 98
    99. Abstraction FTW db_query($cluster_name, $sql) DjangoCon 2008 99
    100. No sharding DjangoCon 2008 100
    101. WTF is sharding? All about books DjangoCon 2008 101
    102. Dewey Decimal DjangoCon 2008 102
    103. But it can’t do everything DjangoCon 2008 103
    104. Makes some things ‘impossible’ No shard walking DjangoCon 2008 104
    105. DjangoCon 2008 105
    106. Django knows our models It’s possible DjangoCon 2008 106
    107. If we accept constraints DjangoCon 2008 107
    108. No external sequences DjangoCon 2008 108
    109. Auto-incs can be bad master/master shards DjangoCon 2008 109
    110. No automatic denormalization DjangoCon 2008 110
    111. Counters would be easy! DjangoCon 2008 111
    112. And copied fields too DjangoCon 2008 112
    113. High Performance DjangoCon 2008 113
    114. It’s slow! DjangoCon 2008 114
    115. DjangoCon 2008 115
    116. DjangoCon 2008 116
    117. There are limits But they only apply When being really silly DjangoCon 2008 117
    118. Sessions DjangoCon 2008 118
    119. OMG UR ON CRAK DjangoCon 2008 119
    120. Extra DB table A read on every page DjangoCon 2008 120
    121. Lightweight = better DjangoCon 2008 121
    122. Signed cookies DjangoCon 2008 122
    123. No parallelization DjangoCon 2008 123
    124. Multiple cache-requests DjangoCon 2008 124
    125. Multiple multi-keyed reads DjangoCon 2008 125
    126. Slow HTTP requests while we’re doing other stuff DjangoCon 2008 126
    127. Creates dumb SQL DjangoCon 2008 127
    128. foo.exclude(bar = true) WHERE (NOT (bar = 1)) DjangoCon 2008 128
    129. foo.exclude(bar = true) WHERE bar != 1 DjangoCon 2008 129
    130. foo.filter(bar = false) WHERE bar = 0 Indexable! DjangoCon 2008 130
    131. Maintainability DjangoCon 2008 131
    132. Maintainability Awesomeness DjangoCon 2008 132
    133. Verbose template syntax <h1>{{ foo.bar }}</h1> DjangoCon 2008 133
    134. <h1>{{ foo.bar }}</h1> <h1>{$foo.bar}</h1> 3 extra characters! DjangoCon 2008 134
    135. <h1>{{ foo.bar }}</h1> <h1>{$foo.bar|e}</h1> Well almost… DjangoCon 2008 135
    136. {% if edit_mode %} woo {% endif %} {if $edit_mode} woo {/if} 9 extra! DjangoCon 2008 136
    137. Verbose template syntax makes people cry DjangoCon 2008 137
    138. No query debugger DjangoCon 2008 138
    139. >>> from django.db import connection >>> connection.queries [{'sql': 'SELECT polls_polls.id,polls_polls.question,polls_ polls.pub_date FROM polls_polls', 'time': '0.002'}] DjangoCon 2008 139
    140. >>> from django.db import connection >>> connection.queries [{'sql': 'SELECT polls_polls.id,polls_polls.question,polls_ polls.pub_date FROM polls_polls', 'time': '0.002'}] Not good enough! DjangoCon 2008 140
    141. Better, but not amazing DjangoCon 2008 141
    142. DjangoCon 2008 142
    143. Page summary DjangoCon 2008 143
    144. Make it clickable… DjangoCon 2008 144
    145. EXPLAIN is AWESOME DjangoCon 2008 145
    146. And/or show the data DjangoCon 2008 146
    147. MySQL Query Profiler Enough data to choke a whale DjangoCon 2008 147
    148. Not smug enough DjangoCon 2008 148
    149. DjangoCon 2008 149
    150. DjangoCon 2008 150
    151. Unreadable SQL SELECT `app_userprofile`.`user_id`,`app_userprofile`.`account_status`,`app_userp rofile`.`account_status_reason`,`app_userprofile`.`account_delete_type`,` app_userprofile`.`syndication_key`,`app_userprofile`.`blurb`,`app_userpro file`.`location`,`app_userprofile`.`country`,`app_userprofile`.`postal_code`,` app_userprofile`.`gender`,`app_userprofile`.`theme`,`app_userprofile`.`tiny _photo`,`app_userprofile`.`small_photo`,`app_userprofile`.`smedium_pho to`,`app_userprofile`.`medium_photo`,`app_userprofile`.`large_photo`,`ap p_userprofile`.`orig_photo`,`app_userprofile`.`bday_month`,`app_userpro file`.`bday_day`,`app_userprofile`.`bday_year`,`app_userprofile`.`is_pro`,`a pp_userprofile`.`privacy_settings_id`,`app_userprofile`.`email_settings_id `,`app_userprofile`.`preference_settings_id`,`app_userprofile`.`ad_counte r`,`app_userprofile`.`num_friends`,`app_userprofile`.`num_fans`,`app_user profile`.`num_feeds`,`app_userprofile`.`num_blocked_fans`,`app_userpro file`.`num_friend_requests`,`app_userprofile`.`default_set_id`,`app_userpr ofile`.`invite_id`,`app_userprofile`.`invite_round`,`app_userprofile`.`avail_in vites`,`app_userprofile`.`original_email` FROM `app_userprofile` WHERE (`app_userprofile`.`user_id` = 1) DjangoCon 2008 151
    152. Unreadable SQL SELECT * FROM `app_userprofile` WHERE `user_id` = 1 DjangoCon 2008 152
    153. SELECT * is fast! Faster over the wire Faster to parse Easier to debug DjangoCon 2008 153
    154. Unreadable SQL SELECT `app_note`.`id`,`app_note`.`type`,`app_note`.`body`,`app_note `.`sender_id`,`app_note`.`date_sent`,`app_note`.`num_recipie nts`,`app_note`.`recipient_type`,`app_note`.`set_id`,`app_not e`.`direct_to_id`,`app_note`.`media_file_id`,`app_note`.`url`,`a pp_note`.`url_inline`,`app_note`.`url_clicks`,`app_note`.`embe d_id`,`app_note`.`event_id`,`app_note`.`is_direct`,`app_note`.` is_public`,`app_note`.`is_deleted`,`app_note`.`is_ad`,`app_no te`.`reply_to_id`,`app_note`.`forwarded_from_id`,`app_note`.` original_note_id`,`app_note`.`stars`,`app_note`.`rsvp` FROM `app_note` LEFT OUTER JOIN `app_userprofile_notes` AS `m2m_app_note__recipients` ON `app_note`.`id` = `m2m_app_note__recipients`.`note_id` WHERE ((NOT (`app_note`.`is_deleted` = True)) AND `m2m_app_note__recipients`.`userprofile_id` = 17573) ORDER BY `app_note`.`date_sent` DESC LIMIT 16 DjangoCon 2008 154
    155. Unreadable SQL SELECT n.* FROM app_note AS n LEFT OUTER JOIN app_userprofile_notes AS l ON n.id=l.note_id WHERE n.is_deleted = False AND l.userprofile_id=17573 ORDER BY n.date_sent DESC LIMIT 16 DjangoCon 2008 155
    156. Django makes me scared of joins DjangoCon 2008 156
    157. Actually, JOINs are evil DjangoCon 2008 157
    158. DjangoCon 2008 158
    159. Low version number DjangoCon 2008 159
    160. DjangoCon 2008 160
    161. DjangoCon 2008 161
    162. Suspiciously small Django: 105 klocs Flamework: 260 klocs DjangoCon 2008 162
    163. Suspiciously small Very long lines? DjangoCon 2008 163
    164. Can’t pluralize octopus DjangoCon 2008 164
    165. Commit all fields at once DjangoCon 2008 165
    166. Race conditions! DjangoCon 2008 166
    167. Dirty flags DjangoCon 2008 167
    168. Don’t make Malcolm cry DjangoCon 2008 168
    169. No simple way to inc/dec DjangoCon 2008 169
    170. UPDATE foo SET x=x+1 Makes consistency hard! DjangoCon 2008 170
    171. Character encoding Input validation? DjangoCon 2008 171
    172. Character encoding Input validation? (Probably broken) DjangoCon 2008 172
    173. No mascot!?! DjangoCon 2008 173
    174. Echidna? DjangoCon 2008 174
    175. MAGICAL POWERS DjangoCon 2008 175
    176. No deployment system DjangoCon 2008 176
    177. Extending models Tables are never big enough DjangoCon 2008 177
    178. Model changes manage.py reset appname DjangoCon 2008 178
    179. django-evolution dmigrations DjangoCon 2008 179
    180. What’s django done for you lately? DjangoCon 2008 180
    181. thanks (now go make it better)
    182. Photo credits flickr.com/photos/wilson/18685396/ flickr.com/photos/sharynmorrow/2571566304/ • • flickr.com/photos/uhop/105063089/ flickr.com/photos/florathexplora/286035943/ • • flickr.com/photos/plasticbag/91453376/ flickr.com/photos/webguru4god/2233500779/ • • flickr.com/photos/zenoc/1408162618/ flickr.com/photos/emdot/195189924/ • • flickr.com/photos/subinev/27810058/ flickr.com/photos/kayepants/391645870/ • • flickr.com/photos/kaptainkobold/2531797176/ flickr.com/photos/ppowers/793939285/ • • flickr.com/photos/esti/243781036/ flickr.com/photos/dinesh_valke/425540358/ • • flickr.com/photos/oneras/253617128/ flickr.com/photos/hawkexpress/306276212/ • • flickr.com/photos/josefstuefer/72512671/ flickr.com/photos/cedric1981/383614033/ • • flickr.com/photos/pgoyette/168076182/ flickr.com/photos/macspite/1118042091/ • • flickr.com/photos/paulhammond/2825869449/ flickr.com/photos/jpstanley/1440357613/ • • flickr.com/photos/nez/378348754/ flickr.com/photos/ashclements/248887492/ • • flickr.com/photos/calevans/2265863104/ flickr.com/photos/kecko/1876479840/ • • flickr.com/photos/mbiddulph/416190643/ flickr.com/photos/difusa/131100622/ • • flickr.com/photos/obliterated/2249663391/ flickr.com/photos/amagill/378984660/ • • flickr.com/photos/salim/67753003/ flickr.com/photos/bea_k63w-wa/2466009108/ • • flickr.com/photos/sosalem/2816909110/ flickr.com/photos/namullim/2096115820/ • • flickr.com/photos/radiorover/324193883/ flickr.com/photos/lotterymonkey/175248733/ • • flickr.com/photos/nickwheeleroz/2773776799/ flickr.com/photos/13519089@N03/1380483002/ • • flickr.com/photos/rse/22972901/ flickr.com/photos/gswj/10344097/ • • flickr.com/photos/rougerouge/534615363/ flickr.com/photos/deanj/67607256/ • • flickr.com/photos/hawkexpress/386355092/ flickr.com/photos/malias/2218694639/ • • flickr.com/photos/escalla/438817719/ flickr.com/photos/clintjcl/120760767/ • • flickr.com/photos/mknightphoto/2295688304/ flickr.com/photos/grandpamikey/2228239585/ • • flickr.com/photos/petereed/138369750/ flickr.com/photos/lea/2829752510/ • • flickr.com/photos/superamit/196481424/ • DjangoCon 2008 182
    183. More photo credits flickr.com/photos/simon999/2419051858/ flickr.com/photos/jordanroher/228435564/ • • flickr.com/photos/tonyjcase/2172060723/ flickr.com/photos/tambako/2524829095/ • • flickr.com/photos/heypaul/1428681/ flickr.com/photos/66132721@N00/2725908636/ • • flickr.com/photos/swisscan/2308034084/ flickr.com/photos/freeparking/1279927021/ • • flickr.com/photos/apollonia666/310793656/ flickr.com/photos/drurydrama/1352506223/ • • flickr.com/photos/bdorfman/15846725/ flickr.com/photos/mn_francis/397620193/ • • flickr.com/photos/wishymom/566394520/ flickr.com/photos/dramaqueennorma/273371415/ • • flickr.com/photos/jgarber/121886004/ flickr.com/photos/chasqui/2338990305/ • • flickr.com/photos/eole/380316678/ flickr.com/photos/cityhunter12/2574288725/ • • flickr.com/photos/917press/1940509163/ flickr.com/photos/akbuthod/1508537255/ • • flickr.com/photos/wallyg/476718069/ flickr.com/photos/nunoforos/2811186142/ • • flickr.com/photos/biwook/390088839/ flickr.com/photos/marcusjb/432600086/ • • flickr.com/photos/bdjsb7/1674027307/ flickr.com/photos/12495774@N02/2405297371/ • • flickr.com/photos/naveenroy/314965221/ flickr.com/photos/larimdame/572477975/ • • flickr.com/photos/wyldkyss/2757474674/ flickr.com/photos/harryharris/1525946537/ • • flickr.com/photos/orinrobertjohn/409812627/ flickr.com/photos/davemorris/91808851/ • • flickr.com/photos/candiedwomanire/1651870/ flickr.com/photos/aplumb/121285138/ • • flickr.com/photos/dalvenjah/408497650/ flickr.com/photos/peebot/825451566/ • • flickr.com/photos/krikit/2657457178/ flickr.com/photos/reillyb/2216541900/ • • flickr.com/photos/w5nyv/2370344/ flickr.com/photos/steffe/423086866/ • • flickr.com/photos/jordanfischer/72510316/ flickr.com/photos/ciordia/255983919/ • • flickr.com/photos/tedsblog/91531710/ flickr.com/photos/wwworks/2472230611/ • • flickr.com/photos/celesterc/1069893367/ flickr.com/photos/pnoid00/1909096140/ • • flickr.com/photos/spacematters/766372252/ flickr.com/photos/jurvetson/2229899/ • • flickr.com/photos/esti/147733640/ flickr.com/photos/foxypar4/766801643/ • • flickr.com/photos/rbp/2833593771/ flickr.com/photos/wizardhere/2413404079/ • • DjangoCon 2008 183
    184. these slides are online: iamcal.com/talks DjangoCon 2008 184

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