| 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. |
