October Meet Minutes

Meet-up held on sunny pleasant day, with auditorium filled with audience ready for talks as Vijay Kumar outlined the purpose of meet-up and agenda.

Postgres Explain

First talk was given by Abishek Postgresql "EXPLAIN". He started with general audience poll on query optimization and query performance. He then explain the usage of "EXPLAIN" which verify our speculation and gives us cost of query while "EXPLAIN ANALYSE" actually runs the query and gives cost of query. He explained the anatomy of "EXPLAIN" output and described startup cost and end cost, where end cost is what we generally take into consideration.

His talks consisted riddles in form of audience polls. One riddle was with filters whether "WHERE" would result in low cost or not. Infact "WHERE" clause increases the cost. Another riddle followed, whether creating "INDEX" on query would optimize the query or not. Result was surprising since "INDEX" didn't reduce the cost, it's because low cardinality indexes are ignored. Next quiz was on "JOIN", adding "INDEX" on "JOIN" clause also doesn't improve the cost. In fact "JOIN" doesn't use index in any step, to improve efficiency for "JOIN" better idea would be to use filter clause on one of the table. The last quiz included "ORDER BY", adding "INDEX" while using "ORDER BY" clause really improves the cost, which was the key take away from the talk.

Introduction to pgcli and mycli

Next talk by amjith(@amjithr) complemented the previous one in huge way by adding CLI tool for postgresql queries. He is the author of pgcli(pgcli.com) and mycli(mycli.net). He right away got into demo of pgcli. He demoed auto completion feature with fuzzylogic completion. Syntax highlight and meta commands completion were also incentives of pgcli. PGCLI don't need semicolons for one line commands while multiline mode needs them. Talk was purpose wasn't to introduce to his tools, he wanted to dissipate knowledge on building tools for modern CLI. He introduced tools which would help in building on CLI tools including PTPYTHON which is awesome python repl, WHARFEE which is docker shell interface, SAWS which is wonderful for AWS shell interface and PYVIM which is Vim clone in Python. He further introduced PROMPT TOOLKIT which is helpful in auto-completion and PYGMENTS which is helps in syntax highlighting. He also introduces fuzzy-finder algorithm built by him and a blog post regarding the same. CLICK is also nice tool for CLI helper methods. He concluded the talk with question from audience and his contact details.

Networking Tea Break

Image Processing using OpenCV

Next talk was by HariPriya Bhaskar on OpenCV. She started her talk with an inspiring self-driving car video which has application of OpenCV. She then headed over to short demo of object tracking using HSV value parameter. She then explained the corresponding code used in the demo of object tracking. She ended her talk with another video on future concept of applications of OpenCV in augmented reality domain. On taking questions from audience she in-depth explained the "GAIT" analysis in her project, in her clinical project she used handy-cam and OpenCV for tracking movement of patient to give them feedback. Shrayas further added to info about "GAIT" analysis used by professional athletes.

Pretty Printing in Python

The last talk was by open source rock-star aka Shakthi Kannan. His talk was on "Pretty Printing in Python" i.e 3D printing using python. He showed Prusa Mendel Hardware which he uses. Motivation of talk was to build stuff by yourself without any need proprietary software and hardware. He showed the SUPERMAN and BATMAN logo he built with the printer. He quickly dived into the software he used for giving instruction to printer. He pointed out the need for STL as end goal for draw the object. Gcode is sent to arduino which handles the further instructions. He then introduced suite for 3D printing like "printrun" and "Skeinforge". He also mentioned "Blender" for 3D modelling, Meshlab clould for real object and "pylatscan" for scanning real objects and "rep rap" and "blenderpython". He concluded his talk with credits to people on Internet and his colleagues and interns who helped him and mentions of IRC channels to get help from.

Lightning Talks

Next up was for lightning talks, where Shakthi Kannan gave two presentation where one consisted of 3d printing stuff. Another one was awesome rhymes that are going to be prevalent to future software developers. Then I (Gaurav) gave a talk a talk on making reveal.js slides using "Jupyter" aka "Ipython", without going through any hassle. Further Abhishek gave concerning talk about Volkswagen scandal and how developers should be aware and be responsible of their actions and code.

Then Vijay gave closing note of the meet-up with due gratitude to sponsors, IMSc and participants. We then had a group photos which concluded the evening with discussion.

Minutes contributed by Gaurav Sherawat.

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