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TNS:could not resolve the connect identifier specified
Backtrace message unwound by exceptions
invalid identifier
PL/SQL compilation error
internal error
missing expression
table or view does not exist
end-of-file on communication channel
TNS:listener unknown in connect descriptor
insufficient privileges
PL/SQL: numeric or value error string
TNS:protocol adapter error
ORACLE not available
target host or object does not exist
invalid number
unable to allocate string bytes of shared memory
resource busy and acquire with NOWAIT specified
error occurred at recursive SQL level string
ORACLE initialization or shutdown in progress
archiver error. Connect internal only, until freed
snapshot too old
unable to extend temp segment by string in tablespace
Credential retrieval failed
missing or invalid option
invalid username/password; logon denied
unable to create INITIAL extent for segment
out of process memory when trying to allocate string bytes
shared memory realm does not exist
cannot insert NULL
TNS:unable to connect to destination
remote database not found ora-02019
exception encountered: core dump
inconsistent datatypes
no data found
TNS:operation timed out
PL/SQL: could not find program
existing state of packages has been discarded
maximum number of processes exceeded
error signaled in parallel query server
ORACLE instance terminated. Disconnection forced
TNS:packet writer failure
see ORA-12699
missing right parenthesis
name is already used by an existing object
cannot identify/lock data file
invalid file operation
quoted string not properly terminated

Index suppression

genegurevich

2006-08-03

Replies:
Hello everybody:

I stumbled upon a SQL which executes in 20 to 30 sec the way it has been
written. If I however suppress one index
by replacing "table1.col1 = table2.col1" with "table1.col1+0 =
table2.col1", the query executes in under 0.1sec.
The explain plan shows that in the original version oracle accesses table1
via a primary key and then reads
data from the table. In the modified version oracle does a full table scan.
As the table1 only has 10000 rows,
full table scan is probably faster than an index read followed by the table
read.

So I wonder why does oracle optimizer (my version is 9204) insists on using
the index and how can I force
it to be smarter. My optimizer_index_costr_adj is 100, which makes index
as expensive as possible (I think).
I can't change the multiblock_read_count. Is there anything else I am
missing?


thank you

Gene Gurevich


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