performance issue on Table
Posted in 2020
Topics: Performance & Tuning
Hi All, We had a table of 260GB which was round robin fragmented with 4 partitions. It hit the pages per fragment limit and we have added 4 more new fragment. Since then application team is complaining about slow performance. Any idea what could be the issue and ways to troubleshoot or any workaround. ------------------------------ Sandip Nawale ------------------------------ #Informix
The slowness is because the engine is trying to put data into the 4 full partitions 50% of the time. You need to redistribute the data across all 8 partitions with: ALTER FRAGMENT ON TABLE INIT ROUND ROBIN IN ... ------------------------------ Art Kagel ------------------------------
Hi Sandip, the solution is: set AUTOLOCATE greater as the default 0. e.g. AUTOLOCATE=1 . This will bring you back to the same performance as before. BUT: Please note, that AUTOLOCATE have many site effects during creating tables/indizes AND during Fragment extensions at runtime. We ( leolo IT) working hard with Informix advanced support at TS004062092. The behavior of AUTOLOCATE is not deep enough tested from the R&D team. Means, we run in some funny auto creation of new table partitions (nobody fin the reason until, yet). At summary: your performance issue will fixed, but please note the unstable behavior of the AUTOLOCATE > 0 setting. Maybe you set this in your session local to push this special batch job. Be care, Henri ------------------------------ Henri Cujass leolo IT, CTO Germany ------------------------------