Import items perfomance issue

Hi

Insert 30000 rows into mtl_item_revisions_interface, mtl_system_items_interface, mtl_item_categories_interface, run Import items program, the performance is poor. When import 5000 rows, performance is fine.

From trace file , see that:

VERALL TOTALS FOR ALL NON-RECURSIVE STATEMENTS

call     count       cpu    elapsed       disk      query    current        rows
------- ------  -------- ---------- ---------- ---------- ----------  ----------
Parse       23      0.01       0.01          0          0          0           0
Execute     38      0.05       0.13          0         60          1           3
Fetch       32      0.79       1.94       1402     279025          0          49
------- ------  -------- ---------- ---------- ---------- ----------  ----------
total       93      0.85       2.09       1402     279085          1          52

Misses in library cache during parse: 20
Misses in library cache during execute: 18

Elapsed times include waiting on following events:
Event waited on                             Times   Max. Wait  Total Waited
----------------------------------------   Waited  ----------  ------------