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INITRANS? [message #63436] Tue, 05 October 2004 02:06 Go to next message
Vivek Vijai
Messages: 67
Registered: April 2004
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Can anyone tell me wats the Purpose of INITRANS parameter.

As it guarantees the minimum level of concurrency. If its=5 then it insures that minimum 5 transactions can concurrently make changes to the block.

Now my question is if no of transactions is less than 5 then we cant make changes to the block unless it equals or exceeds 5?

So wats the purpose of this parameter.

Vivek

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Re: INITRANS? [message #63439 is a reply to message #63436] Tue, 05 October 2004 02:31 Go to previous messageGo to next message
Frank Naude
Messages: 4580
Registered: April 1998
Senior Member
Hi,

An INITRANS value of 5 means that Oracle will pre-allocate space in each block to handle 1, 2, 3, 4, or 5 concurrent transactions. As soon as the concurrency exceeds INITRANS, Oracle will try to allocate more transaction slots (up to MAXTRANS) within the FREESPACE of the block. If no free space is available users will queue on the available slots (bad).

In general one should not change the INITRANS and MAXTRANS values from their defaults, and ways allow some free space in each block (think twice before you set PCTFREE to 0!).

Best regards.

Frank

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Re: INITRANS? [message #333241 is a reply to message #63439] Fri, 11 July 2008 00:12 Go to previous messageGo to next message
balaji1482
Messages: 312
Registered: July 2007
Location: INDIA
Senior Member
That was a very good explanation about initrans .

"As you say, In general one should not change the INITRANS and MAXTRANS values from their defaults"

we all know default initrans for table is 2 and for index ,it is 1.but if it is the case we find many users are in queue for the indexes then what can be the solution for that??

[Updated on: Fri, 11 July 2008 00:13]

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Re: INITRANS? [message #333267 is a reply to message #333241] Fri, 11 July 2008 01:36 Go to previous messageGo to next message
Michel Cadot
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Registered: March 2007
Location: Nanterre, France, http://...
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Quote:
we all know default initrans for table is 2 and for index

Maybe you know this but it is wrong, default is 1 for table and 2 for index.

Quote:
.but if it is the case we find many users are in queue for the indexes then what can be the solution for that??

There is no queue unless you exceed MAXTRANS or there is no free space.
If you know that an index or a table will regularly exceed the default value then create your objects with a higher initial value.

Regards
Michel

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Re: INITRANS? [message #333387 is a reply to message #333267] Fri, 11 July 2008 08:19 Go to previous messageGo to next message
balaji1482
Messages: 312
Registered: July 2007
Location: INDIA
Senior Member
yes, we are doing the same like increasing the initrans from lower to some higher value for some objects which are in queue .but still we can see ITL waits in AWR report for the same object.

Is there any other solution than increasing the initrans??

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Re: INITRANS? [message #333393 is a reply to message #333387] Fri, 11 July 2008 09:06 Go to previous message
Michel Cadot
Messages: 68672
Registered: March 2007
Location: Nanterre, France, http://...
Senior Member
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Before searching a solution you have to investigate and quantify why.

Regards
Michel

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