Skip to Main Content
Forums

Oracle Database Discussions

Announcement

For appeals, questions and feedback about Oracle Forums, please email oracle-forums-moderators_us@oracle.com. Technical questions should be asked in the appropriate category. Thank you!

Index Range scan cost ?

448778Dec 28 2008 — edited Dec 29 2008
Why the effective index selectivity of index range scan is calculated this way

(highendval -lowendval)/(highvalue -lowvalue)+ 2/num_distinct ?why its not 1/num_distinct which is used in case of equality predicate?


Second question is why the effective index selectivity calculation for a composite index is calculated differently if there is range scan on the leading column of the indexes and though there are predicates available in the where clause for other column in the index why the cost of those predicates is not included in the index range scan.

e.g I have composite index on (n1,n2,n3) and the where clause is

n1 between 6 and 9 and
n2=3 and
n3='a'

why only the effective index selectivity of the index range scan for the predicate n1 is used in finding effective Index selectivity , but all n1,n2 and n3 are considered in getting effective table selectivity(which makes sense)

P.S:- I am refering Cost based fundamental by Jonathan Lewis.

Edited by: user445775 on Dec 28, 2008 11:06 AM

Comments

865505
Here is the hot spot error log.


[ebiz40@DL-CM-TASHA ~]$ cat /home/ebiz40/hs_err_pid30864.log
#
# An unexpected error has been detected by Java Runtime Environment:
#
# SIGBUS (0x7) at pc=0x00002aaaab03f031, pid=30864, tid=1119217984
#
# Java VM: Java HotSpot(TM) 64-Bit Server VM (11.0-b16 mixed mode linux-amd64)
# Problematic frame:
# C [libzip.so+0xb031]
#
# If you would like to submit a bug report, please visit:
# http://java.sun.com/webapps/bugreport/crash.jsp
# The crash happened outside the Java Virtual Machine in native code.
# See problematic frame for where to report the bug.
#

--------------- T H R E A D ---------------

Current thread (0x00002aaac4096c00): JavaThread "TBSU-ImportProcess" [_thread_in_native, id=31253, stack(0x0000000042a5e000,0x0000000042b5f000)]

siginfo:si_signo=SIGBUS: si_errno=0, si_code=2 (BUS_ADRERR), si_addr=0x00002aaac2224af1

Registers:
RAX=0x0000000000000000, RBX=0x000000005470d9e8, RCX=0x0000000000000070, RDX=0x00002aaac8b62b30
RSP=0x0000000042b5be80, RBP=0x00002aaac2224ad4, RSI=0x00000035291529e0, RDI=0x00002aaac80001e8
R8 =0x0000000000000000, R9 =0x0000000000000000, R10=0x00002aae378c5418, R11=0x00002aae378c8e88
R12=0x00002aaac8b62af0, R13=0x000000005470b460, R14=0x0000000042b5bf10, R15=0x0000000000000029
RIP=0x00002aaaab03f031, EFL=0x0000000000010206, CSGSFS=0x0000000000000033, ERR=0x0000000000000004
TRAPNO=0x000000000000000e
Does your code or the third party code use native code (JNI)?
866439
I am also facing the exact issue. Did you find any solution for this?
802316
I had a similar problem with Java 6 update 18 when reading a truncated ZIP/JAR file.

Since using Java 6 update 23 and 25 I haven't had this problem.
866439
We have 1.5.0_22-b03 on testing environment and it is working fine. But same 1.5.0_22-b03 in production environment is having the issue.
1 - 5
Locked Post
New comments cannot be posted to this locked post.

Post Details

Locked on Jan 26 2009
Added on Dec 28 2008
#for, #general-database-discussions, #index, #to
3 comments
1,651 views