Re: [Firebird-devel] Firebird 2.5: Performance degradation and increasing file size

[Dmitry Y. <fir...@ya...>]

All,

The issue could be caused by the garbage records inside 
RDB$USER_PRIVILEGES. It seems that nobody can collect it in the 
cooperative mode, as permissions are always read by the object name but 
after dropping it's no longer known to anyone.

After the first test run I can see about 9000 record versions linked to 
the current user and different dropped tables. Every DROP TABLE 
statement invokes MET_revoke() which queries permissions using both the 
object name and the user name and both these predicates are mapped to 
indices. The last one requires a full index scan in this test case. 
During the next run the index scan takes more time (as the number of 
garbage keys grows) and so on. Running "select count(*) from 
rdb$user_privileges" between runs seem curing the problem (at the first 
glance).

There are no stuck transactions there.


Dmitry