Usage limits

The E-Maj extension usage has some limits:

  • The minimum required PostgreSQL version is 9.5.
  • All tables belonging to a “ROLLBACKABLE” tables group must have an explicit PRIMARY KEY. If a table has no explicit PRIMARY KEY but has a UNIQUE index referencing NOT NULL columns, this index should rather be transformed into PRIMARY KEY.
  • UNLOGGED and WITH OIDS tables can only be members of “audit_only” tables groups.
  • TEMPORARY tables are not supported by E-Maj.
  • Using a global sequence for a database leads to a limit in the number of updates that E-Maj can manage throughout its life. This limit equals 2^63, about 10^19 (but only 10^10 on oldest platforms), which still allow to record 10 million updates per second (100 times the best performance benchmarks results in 2012) during … 30,000 years (or at worst 100 updates per second during 5 years). Would it be necessary to reset the global sequence, the E-Maj extension would just have to be un-installed and re-installed.
  • If a DDL operation is executed on an application table belonging to a tables group, E-Maj is not able to reset the table in its previous state. (more details here)