Database Export
|
===============
|
|
perf tool's python scripting engine:
|
|
tools/perf/util/scripting-engines/trace-event-python.c
|
|
supports scripts:
|
|
tools/perf/scripts/python/export-to-sqlite.py
|
tools/perf/scripts/python/export-to-postgresql.py
|
|
which export data to a SQLite3 or PostgreSQL database.
|
|
The export process provides records with unique sequential ids which allows the
|
data to be imported directly to a database and provides the relationships
|
between tables.
|
|
Over time it is possible to continue to expand the export while maintaining
|
backward and forward compatibility, by following some simple rules:
|
|
1. Because of the nature of SQL, existing tables and columns can continue to be
|
used so long as the names and meanings (and to some extent data types) remain
|
the same.
|
|
2. New tables and columns can be added, without affecting existing SQL queries,
|
so long as the new names are unique.
|
|
3. Scripts that use a database (e.g. exported-sql-viewer.py) can maintain
|
backward compatibility by testing for the presence of new tables and columns
|
before using them. e.g. function IsSelectable() in exported-sql-viewer.py
|
|
4. The export scripts themselves maintain forward compatibility (i.e. an existing
|
script will continue to work with new versions of perf) by accepting a variable
|
number of arguments (e.g. def call_return_table(*x)) i.e. perf can pass more
|
arguments which old scripts will ignore.
|
|
5. The scripting engine tests for the existence of script handler functions
|
before calling them. The scripting engine can also test for the support of new
|
or optional features by checking for the existence and value of script global
|
variables.
|
