https://metalink.oracle.com/metalink/plsql/ml2_documents.showDocument?p_database_id=NOT&p_id=465840.1 Configuring Temporary Tablespaces for RAC Databases for Optimal Performance https://metalink.oracle.com/metalink/plsql/ml2_documents.showDocument?p_database_id=NOT&p_id=459036.1 Temporary tablespace SS Contention In RAC > Temporary tablespace is specific to each instance in RAC. The total is 100%. select * from gv$temp_space_header; select * from gv$temp_extent_pool; The second view is interesting. There's a concept of temp space caching that happens locally to an instance. It does not mean you can only use that temp space in your local cache. Suppose it's used up, it should be able to grab temp space from other instances. select * from gv$tempstat; Each instance has its own statistics. Yong Huang SQL> set tab off -- Two instances have exactly the same content SQL> select * from gv$temp_space_header; INST_ID TABLESPACE_NAME FILE_ID BYTES_USED BLOCKS_USED BYTES_FREE BLOCKS_FREE RELATIVE_FNO ------- --------------- ------- ---------- ----------- ---------- ----------- ------------ 1 TEMP 3 2097152000 256000 0 0 2 1 TEMP 4 1919942656 234368 177209344 21632 3 1 TEMP 5 1917845504 234112 179306496 21888 4 1 TEMP 1 2097152000 256000 0 0 1 1 TM_TMP 2 1048576 128 103809024 12672 1 2 TEMP 3 2097152000 256000 0 0 2 2 TEMP 4 1919942656 234368 177209344 21632 3 2 TEMP 5 1917845504 234112 179306496 21888 4 2 TEMP 1 2097152000 256000 0 0 1 2 TM_TMP 2 1048576 128 103809024 12672 1 10 rows selected. -- Note the difference between the two instances SQL> select * from gv$temp_extent_pool; INST_ID TABLESPACE_NAME FILE_ID EXTENTS_CACHED EXTENTS_USED BLOCKS_CACHED BLOCKS_USED BYTES_CACHED BYTES_USED RELATIVE_FNO ------- --------------- ------- -------------- ------------ ------------- ----------- ------------ ---------- ------------ 1 TEMP 1 1998 0 255744 0 2095054848 0 1 1 TEMP 3 1999 0 255872 0 2096103424 0 2 1 TEMP 4 1827 0 233856 0 1915748352 0 3 1 TEMP 5 1827 1 233856 128 1915748352 1048576 4 2 TEMP 1 1 0 128 0 1048576 0 1 2 TEMP 3 0 0 0 0 0 0 2 2 TEMP 4 3 0 384 0 3145728 0 3 2 TEMP 5 1 0 128 0 1048576 0 4 SQL> select * from gv$tempstat order by 1, 2; INST_ID FILE# PHYRDS PHYWRTS PHYBLKRD PHYBLKWRT SINGLEBLKRDS READTIM WRITETIM SINGLEBLKRDTIM AVGIOTIM LSTIOTIM MINIOTIM MAXIORTM MAXIOWTM ------- ----- -------- ------- ---------- ---------- ------------ ------- ---------- -------------- ---------- ---------- ---------- ---------- ---------- 1 1 1362097 284431 4711413 8260361 3812 224 98 201 0 1 0 5 40 1 2 326426 233652 4075388 5207543 64 2213 38 12 0 1 0 55 38 1 3 215109 372493 3758194 9281026 2368 240 133 96 0 0 0 10 38 2 1 24733 42294 556392 728809 6240 362 0 192 0 0 0 2 0 2 2 89733 27849 649846 641518 29646 1436 0 1436 0 0 0 12 0 2 3 15201 33582 395198 606001 2324 100 0 96 0 1 0 1 0