P.S. Guess the operation meaning,
@ kdiixs: Index Scan;
@ kdsgrp: Access table by index rowid.
Where is the other reads Look at the 1st'db file sequential read', the block was physically read without pining. What'skind of such block Get its datablock address first,
SQL代码
SQL>selectto_char(dbms_utility.make_data_block_address(5, 66164), 'XXXXXXXX') fromdual;
TO_CHAR(D
---------
1410274
Then, dump the index tree.
SQL代码
SQL>alter session setevents 'immediate trace name treedump level 100897';
Session altered.
Here is the tree,
SQL代码
----- begin tree dump
pin kdxwh40: kdxdtree dba1410274:1 time 2048438778
branch: 0x1410274 21037684(0: nrow: 6, level: 1)
pin release 5331 kdxwh40: kdxdtree dba 1410274:1
pin kdxwh40: kdxdtree dba1410275:1 time 2048462836
leaf: 0x1410275 21037685 (-1: nrow: 195rrow: 195)
pin release 5645 kdxwh40: kdxdtree dba 1410275:1
pin kdxwh40: kdxdtree dba1410280:1 time 2048471550
leaf: 0x1410280 21037696 (0: nrow: 228 rrow:228)
pin release 5817 kdxwh40: kdxdtree dba 1410280:1
pin kdxwh40: kdxdtree dba1410276:1 time 2048480732
leaf: 0x1410276 21037686 (1: nrow: 461 rrow:461)
pin release 5854 kdxwh40: kdxdtree dba 1410276:1
pin kdxwh40: kdxdtree dba1410277:1 time 2048489433
leaf: 0x1410277 21037687 (2: nrow: 475 rrow:475)
pin release 6145 kdxwh40: kdxdtree dba 1410277:1
pin kdxwh40: kdxdtree dba1410278:1 time 2048498455
leaf: 0x1410278 21037688 (3: nrow: 399 rrow:399)
pin release 5644 kdxwh40: kdxdtree dba 1410278:1
pin kdxwh40: kdxdtree dba1410279:1 time 2048507256
leaf: 0x1410279 21037689 (4: nrow: 314 rrow:314)
pin release 5747 kdxwh40: kdxdtree dba 1410279:1
----- end tree dump
That block is a branch block. Means the branchblock will not be pin in the cache. You can test other higher index tree toprove it.
So far, it comes out the Logical reads, 1branch node read + 2 leaf node scan + 3 access table block by index rowid = 6Logical reads.