I have a big table that gets a lot of inserts. Rows are inserted 10k at a time with a table function. At around 2.5 million rows, inserts slow down from 2-7s to around 15-20s. The table’s dat file is around 800-900M.


I have durability set to “test”, table-level locks, a primary key index and another 2-column index on the table. Page size is at the max and page cache set to 4500 pages. The table gets compressed (inplace) every 500,000 rows. I’m using Derby 10.4 with JDK 1.6.0_07, running on Windows XP. I’ve ruled out anything from the rest of the application, including GC (memory usage follows a consistent pattern during the whole load). It is a local file system. The database has a fixed number of tables (so there’s a fixed number of dat files in the database directory the whole time). The logs are getting cleaned up, so there’s only a few dat files in the log directory as well.


Any ideas what might be causing the big slowdown after so many loads?