Temp space problem

Question

HI all,
I receive an error while executing a procedure.
ORA-01652: unable to extend temp segment by 128 in tablespace TEMP
can any one please exlain what is the problem.
thanks in advance
baskar k

Answer 1

hi
First ORA-01652 may occur because there is simply no space available in the temp tablespace of which is being used. The second cause of ORA-01652 may have to do with the local temp segment not being able to extent space even though there is space in other instances.
To trouble shoot for ORA-01652, and find out which of the above scenarios are causing ORA-01652 use this query offered by MetaLink:
select sum(free_blocks)
from gv$sort_segment
where tablespace_name = '<TEMP TABLESPACE NAME>'
You will know that the first scenario is causing ORA-01652 to be thrown if the free block reads '0' because it signifies that there is no free space.
If there is a good amount of space, you know that there is another cause for ORA-01652, and it is probably the second scenario. It is important to note that in a non-RAC environment, local instances are not able to extend the temp segments, so in the RAC environment, ORA-01652 has to be handled differently. If you are experiencing ORA-01652 in a non-RA environment, be aware that every SQL making use of the tablespace can fail.
In RAC, more sort segment space can be used from other instances, which can help resolve ORA-01652 more easily. Try using the query below:
select inst_id, tablespace_name, total_blocks, used_blocks, free_blocks
from gv$sort_segment;
Basically, you can then find out how much temp segment space can be used for each instance by viewing the total_blocks, and the used_blocks can reveal the space which has been used so far, and and the free_blocks gives the amount of space allocated to this particular instance. This being, to resolve ORA-01652, you can check out that used_blocks = total_blocks and free_blocks = 0 will probably show for the instance, and ORA-01652 will be shown multiple times within the alert log.
This basically means that free space from other instances is being requested, and typically signifies that there is instance contention. Instance contention within the temporary space can make the instance take more time to process.
In sever cases, a slowdown may occur, in which you might want try one of the following work-arounds:
Increase size of the temp tablespace
Increase sort_area_size and/or pga_aggregate_target
However, remember to not use the RAC feature of DEFAULT temp space.
If ORA-01652 is causing the slowdown, SMON will probably not be able to process the sort segment requests, you you should try to diagnose the contention:
Output from the following query periodically during the problem:
select inst_id, tablespace_name, total_blocks, used_blocks, free_blocks
from gv$sort_segment;
Global hanganalyze and systemstate dumps
Hope this helps
CHeers