Re: BMT : informix vs. sybase

hyun-taek. wrote: > > Hi! everyone > > We had done BMT(Informix vs. sybase) last two weeks. > We had checked "TPS(Transaction per second)". > SYBASE 11.0.2 > INFORMIX 7.2.0 > > We found that TPS of informix is very high at the begining time. > but get decreased tremendously. > I think that Informix writes all data on the memory and > after memory is full, it transfers all data to a disk. > The speed of transfering data to a disk is very slow. > It is just my opinion. > So, Do you have any idea on that ? > > this is my E-mail address > > htshin@hei.co.kr > > thank you ! It looks to me like you need some good engine tuning on Informix. From what I gather from your article you are probably experiencing long checkpoints which are caused by many chunk writes. You are probably also encountering foreground writes. Let's give a quick Informix class: Online has 3 types of writes: LRU, chunk and foreground. The ones you want the most are LRU writes, and the one you want the least is the foreground. The first thing to look at is the LRU_MIN_DIRTY (I have it set to 5) and LRU_MAX_DIRTY (I have it set to 7). This should alleviate the problem your having. Of course there are other things to look at but this would probably give you the quickest results.