sqlite/test/speedtest.md

Performance And Size Measurements

This document shows a procedure for making performance and size comparisons between two versions of the SQLite Amalgamation "sqlite3.c". You will need:

• fossil
• valgrind
• tclsh
• A script or program named "open" that brings up *.txt files in an editor for viewing. (Macs provide this by default. You'll need to come up with your own on Linux and Windows.)
• An SQLite source tree

The procedure described in this document is not the only way to make performance and size measurements. Use this as a guide and make adjustments as needed.

Establish the baseline measurement

• Begin at the root the SQLite source tree
• mkdir -p ../speed
  ↑ Speed measurement output files will go into this directory. You can actually put those files wherever you want. This is just a suggestion. It might be good to keep these files outside of the source tree so that "fossil clean" does not delete them.
• Obtain the baseline SQLite amalgamation. For the purpose of this technical note, assume the baseline SQLite sources are in files "../baseline/sqlite3.c" and "../baseline/sqlite3.h".
• test/speedtest.tcl ../baseline/sqlite3.c ../speed/baseline.txt
  ↑ The performance measure will be written into ../speed/baseline.txt and that file will be brought up in an editor for easy viewing.
  ↑ The "sqlite3.h" will be taken from the directory that contains the "sqlite3.c" amalgamation file.

Comparing the current checkout against the baseline

• make sqlite3.c
• test/speedtest.tcl sqlite3.c ../speed/test.txt ../speed/baseline.txt
  ↑ Test results written into ../speed/test.txt and then "fossil xdiff" is run to compare ../speed/baseline.txt against the new test results.

When to do this

Performance and size checks should be done prior to trunk check-ins. Sometimes a seemingly innocuous change can have large performance impacts. A large impact does not mean that the change cannot continue, but it is important to be aware of the impact.

Additional hints

Use the --help option to test/speedtest.tcl to see other available options.