1) so how can i find out whether database is in backward compatibilty?Backwards compatible between what & what?
2) is there any issues with performance after convertingWhat do your regression & benchmark test show
3) or is there any other severe issues other than performance.What do your regression & benchmark test show
4) how can we identifiy the difference interms of performance after migrating from "manual" to "auto".What do your regression & benchmark test show
What do your regression & benchmark test showI have no idea how to conduct these test. give me some idea on this
If we tell you no problem & then your DB stops performing, what will you tell your boss?then no use to post in forum, is it? :) expecting good and better suggetion from experts/gurus.
I have no idea how to conduct these test. give me some idea on thisRun example SQL against DB & measure performance & response time.
If a tablespace is in manual segment space management mode, it will mark only some blocks as header for that tablespace. so header contention will occur first-of-all.Do you mean to say that in the case of the MSSM, its the tablespace header(what's that) would be used ? Its a segment level feature so the contention would be on the segment header as it would be pinned always to start teh search.
While datadictionary managed tablespace and locally managed tablespace acts at tablespace level, freelists acts at block level. So free list is doing it at a fine grained level.What does this statement means? The difference if DMT and LMT lies in this that DMT uses FET$ and UET$ to maintain the information about the "extents" and LMT uses a bit structure to maintain it. The free list, as I mentioned before is a segment level attribute.
The advantage of manual segment space management over ASSM is data will be tightly packed in the datablocks, coz data will get inserted till the pct_free value setting. ie if pct_free=10 , then data will get inserted till 90% of the datablock. only when a block filled upto 90%, then the next datablock will be used.And where did you read this? Post a link here which does say this?
user13364377 wrote:I am not sure that I can agree to your statement. In the formation of a new table, there are three blocks which are formatted in the first extent of the segment. One, the segment header and two blocks for the level 1 and 2 bitmaps. I am not able to understand your "segment headers" concept at all. There is one segment header block AFAIK.
If a tablespace is in manual segment space management mode, it will mark only some blocks as header for that tablespace. so header contention will occur first-of-all.
I was talking about the segment headers...
While datadictionary managed tablespace and locally managed tablespace acts at tablespace level, freelists acts at block level. So free list is doing it at a fine grained level.And this has nothing to do with the OP's question I believe since he is interested to know whether using ASSM would be better or not.
I mean to say that dictionary managed tablespace and locally managed tablespace are tablespace level entities.
and freelist is something which acts on datablocks.