Initrans, why?

[c.boratto]

Dear,

I'm reading the Oracle book from Kyte.

In this book it explains about how Locking is implemented in the bank. He explains that a particular block has a maximum number of 'slots per transaction' (maxtrans) that would be the maximum number of competing transactions in that particular block. OK

However, what is the sense of the initrans? Why a block would have a minimum number of transactions and in that case, why Default 2?
Sorry for my ignorance, he even cites some advantages of applying that larger number, but still, it was not clear to me.

from já,
Thanks

[dr_gori]

Topic Moved for Forum DBA

[pauloaleo]

The initrans defines how many DMLs (INSERT, UPDATES and deletes) can change the same block at the same time.Num fully transactional bank, if the initrans is set to 1 (default) and the size of the block is 8192K and contains, let's Suppose 4 records of a table, only a transaction that makes insert, update or delete can at a time update this block. Consequently, you will see a contention in the Bank by Hotblock, that is, a block highly accessed by several transactions at a time, and only one is answered, the others are on hold.

Inittrans, MaxTrans, PCTFree and PCTINCREASE must be set appropriately for the type of application that will use the database.

There is no formula, number or parameter. Only the application drawing, your size and transactions and defining this.

And incredible as it may seem, you will never see this definition. So you will only realize that the inittrans was erroneously defined, because the bank will contain.

I hope to have explained.

[c.boratto]

Intendi.

But why would I need a minu (initrans) parameter and a maximum (maxtrans)?


then only the maxtrans would be enough, being that, it is very obvious that I will have a transaction in a block ...

MaxTrans already says that you explained .. it is the maximum transactions that can occur simultaneously in that same block ...


in the book it defines As:

"The Initial, PreLocated Size Of This Structure. This default to 2 is index and tables [...]"
pag 214
[ 99] I intend to do so .. by standard ... the block lets book a space for two connection slots and you can according to your need to increase this number (consequently losing space in your block). When someone tries to do access that block if the default limit has already been filled, it would dispose of CPU feature to create that slot at the moment, for example.

I do not know if I'm talking mta bullshit.

But thank you Paul.

[c.boratto]

Just correcting ... what I said in the book is defined is initrans [/b]