Peter, Can you repeat this same issue in SQL*Plus?
-- Ron Reidy Lead DBA Array BioPharma, Inc. -----Original Message----- From: Peter Santos [mailto:[EMAIL PROTECTED] Sent: Thursday, December 08, 2005 9:00 AM To: [email protected] Subject: re: Oracle 10g and DBD::Oracle Dear users, I'm hoping to get some insight into why oracle creates 2 cursors for the same sql query when I execute a SELECT statement via my small little perl script. Here is what is happening .. My query uses 2 bind variables and when it is prepared oracle generates 1 cursor for my query. When I execute that prepared statement with actual input bind variables, it generates a 2nd cursor for the same query. The problem here is that during the prepare, oracle identifies my 2 bind parameters as 2000 character bytes max. When I actually execute the query with the binds, it calculates the bind parameters as 32 characters. So because of bind peeking it thinks it's 2 different queries and generates 2 cursors... where the first cursor has executions=0. I can turn off bind peeking with the parameter "_optim_peek_user_binds", but then instead of just having a cursor mismatch on user_bind_peeking I have a cursor mismatch on "bind_mismatch". Does anyone know how to get around this? This to me is a waste of shared pool resources..and we have lots of this happening in our database. I've asked oracle for help, but I'm getting nowhere... Here is the complete test case. My env: Solaris 8 - Oracle 10.1.0.4 DBI (version 1.48) and DBD::Oracle (version 1.6) ** *TEST TABLE * =========== CREATE TABLE TEST_T1 (column1 varchar2(10), column2 varchar2(10), date_left date); insert into TEST_1 values('Fname','Lname',to_date('20051130 153015','YYYYMMDD HH24MISS'); insert into TEST_1 values('Fname','Lname',to_date('20051130 203015','YYYYMMDD HH24MISS'); *PERL PROGRAM * ============== #!/bin/perl use DBI; my $dbh = DBI->connect( 'dbi:Oracle:;[mydb]', '[username]', '[password]',) || die "Database connection not made: $DBI::errstr"; my $date1 = "20051130"; my $date2 = "20051130"; my $sql = qq{SELECT column1,column2\nfrom TEST_T1\n}; $sql .= qq{WHERE\ndate_left between to_date( :p1 , 'YYYYMMDD') and }; $sql .= qq{to_date( :p2 || ' 235959', 'YYYYMMDD HH24MISS')}; *# prepare select query * my $sth = $dbh->prepare($sql); *# generates cursor1* $sth->bind_param(":p1",$date1); $sth->bind_param(":p2",$date2); $sth->execute(); *# generates cursor2* print "COLUMN1\tCOLUMN2\n"; print "=======\t=======\n"; $sth->bind_columns( \$column1, \$column2); while( $sth->fetch() ) { print "$column1\t$column2\n"; } $dbh->disconnect; exit; *Here is what's in the Oracle data dictionary* HASH_VALUE|SQL_ID | ROWSP| EXECS| CHILD#|CHILD_ADDRESS |MODULE ----------|-------------|------|------|--------|----------------|------- ----------|-------------|------|------|--------|----------------|------- ----------|-------------|------|------|--------|----------------|--- 3546516858|2jwh16z9q73bu| 0| 0|0 |0000040144BD2140|[EMAIL PROTECTED] 3546516858|2jwh16z9q73bu| 2| 1|1 |000004012CECAAF0|[EMAIL PROTECTED] ** So, 1 query and 2 representations of that same query in the database. The execute did not shared the cursor prepared by the prepare() call. SQL > select * from v$sql_shared_cursor where sql_id='2jwh16z9q73bu'; CHILD_ADDRESS |CHILD#|U|S|O|O|S|L|S|E|B|P|I|S|T|A|B|D|L|T|R|I|I|R|L|I|O|S|M|*U*|T| ----------------|------|-|-|-|-|-|-|-|-|-|-|-|-|-|-|-|-|-|-|-|-|-|-|-|-| -|-|-|-|-| 0000040144BD2140|0 |N|N|N|N|N|N|N|N|N|N|N|N|N|N|N|N|N|N|N|N|N|N|N|N|N|N|N|N|N| 000004012CECAAF0|1 |N|N|N|N|N|N|N|N|N|N|N|N|N|N|N|N|N|N|N|N|N|N|N|N|N|N|N|*Y*|N| SQL>select * from v$sql_bind_metadata where address in ('0000040144BD2140','000004012CECAAF0'); *** This shows us that cursor1 had different bind variable metadata than cursor2 which explains why they weren't shared. ADDRESS | POSITION| DATATYPE|MAX_LENGTH| ARRAY_LEN|BIND_NAME ----------------|----------|----------|----------|----------|--------- 0000040144BD2140| 1| 1| 2000| 0|P1 0000040144BD2140| 2| 1| 2000| 0|P2 000004012CECAAF0| 1| 1| 32| 0|P1 000004012CECAAF0| 2| 1| 32| 0|P2 This electronic message transmission is a PRIVATE communication which contains information which may be confidential or privileged. The information is intended to be for the use of the individual or entity named above. If you are not the intended recipient, please be aware that any disclosure, copying, distribution or use of the contents of this information is prohibited. Please notify the sender of the delivery error by replying to this message, or notify us by telephone (877-633-2436, ext. 0), and then delete it from your system.
