@51:55 Postgres could not infer actor_id IS NULL is always false but why doesn’t the query plan take advantage of the primary key index? In other words why isn’t it doing an index scan?
@Andy Pavlo w.r.t to the slide at 26:16 can I write the query in a different way so that resulting tree is like the right tree, to begin with? Or should I assume that this is a compiler optimization and for the most part beyond my control?
Any idea where the study guide he mentions is on the course website? Slides are great study material in and of themselves, but would love to see the study guide.
Are you asking about the lecture notes or the mid-term guide? The lecture notes are in the video description + course schedule: 15445.courses.cs.cmu.edu/fall2019/schedule.html The mid-term guide is only relevant to CMU students (location, time, what they are allowed to bring to the exam).
@@andypavlo Ah, was asking about the mid-term guide. Thought it might have summarized the notes from the previous lectures in a single document. Thanks, Andy!
still shock a db prof can be this cool... gosh..
Miss the DJ
How is the WHERE part of the the query in 53:56 a satisfiability problem ?
A few seconds later, Andy told that it is not. It just need a heuristic.
what's that font used in the slides? looks cool!
57:50 got their ass
missing notes - 15445.courses.cs.cmu.edu/fall2019/notes/14-optimization1.pdf
@51:55 Postgres could not infer actor_id IS NULL is always false but why doesn’t the query plan take advantage of the primary key index? In other words why isn’t it doing an index scan?
I think maybe index cannot help with this. How can an index compare NULL?
@Andy Pavlo w.r.t to the slide at 26:16 can I write the query in a different way so that resulting tree is like the right tree, to begin with?
Or should I assume that this is a compiler optimization and for the most part beyond my control?
You can create a temp table by projecting from second table and then use temp table in final query to join with first table.
Why did he say the method used in MongoDB is super simple and works well? It sounds like an exhaustive method.
I was thinking why the voice was not clear as previous videos then he found out he didn't wear a mic
Any idea where the study guide he mentions is on the course website? Slides are great study material in and of themselves, but would love to see the study guide.
Are you asking about the lecture notes or the mid-term guide? The lecture notes are in the video description + course schedule: 15445.courses.cs.cmu.edu/fall2019/schedule.html
The mid-term guide is only relevant to CMU students (location, time, what they are allowed to bring to the exam).
@@andypavlo Ah, was asking about the mid-term guide. Thought it might have summarized the notes from the previous lectures in a single document. Thanks, Andy!
the demo time is always boring