| 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. |