Lessons learned from projects

Note

Keep updating this page!

Common

Search for gcc include directories

• echo | gcc -E -Wp,-v -
  • For example, math.h : /usr/local/lib/gcc/x86_64-apple-darwin15.6.0/7.2.0/include-fixed/math.h

Hash functions

• MurmurHash3: see wiki

pcre2 Library

• Resources for learning the library: rust-lang/regex, regex engines

Related systems

• Pig Latin Reference Manual 2
• Apache Ignite

SQL

SQL data types

• Online tutorial
• DECIMAL(size,d): A DOUBLE stored as a string , allowing for a fixed decimal point.
  • A trick is to multiply the number with 10^d to convert it from a floating point number to an integer (see the MAL code of tpc-h query 6)

SQLite overview

• Architecture
• Core functions
• Virtual database engine

PL

Floating point precision problem

    0.06 + 0.01 == 0.07
> 0

• Precision in floating number comparison
• Check results by printing P("%.20lf",x)

Not stable sort in NumPy

See discussion

    np.argsort(x) -> np.argsort(x, kind='mergesort')

Hash Join

• An example of hash join
• Hash join in a phd thesis