concat function is HQC cached, but plan for query with concat operator (||) is not HQC cacheable.

[Julie Thai]

>>cqd HQC_LOG 'ON';

--- SQL operation complete.
>>cqd HQC_LOG_FILE 'hqc.log';

--- SQL operation complete.
>>cqd HYBRID_QUERY_CACHE 'ON';

--- SQL operation complete.
>>cqd QUERY_CACHE_USE_CONVDOIT_FOR_BACKPATCH 'ON';

--- SQL operation complete.
>>prepare XX from select CONCAT('AAA', 'BBB') from f00;

--- SQL command prepared.
>>prepare XX from select 'AAA' || 'BBB' from f00;

--- SQL command prepared.
>>prepare XX from select 'CCC' || 'DDD' from f00;

--- SQL command prepared.
>>prepare XX from select CONCAT('AAA', 'BBB') from f00;

--- SQL command prepared.
>>prepare XX from select 'AAA' || 'BBB' from f00;

--- SQL command prepared.
>>prepare XX from select CONCAT('EEE', 'FFF') from f00;

--- SQL command prepared.

From hqc.log:
HQC::AddEntry():
SQL query=select CONCAT('AAA', 'BBB') from f00;
HQC key=SELECT CONCAT ( 'AAA' , 'BBB' ) FROM F00 ;

Not HQC Cacheable but added to SQC:
SQL query=select 'CCC' || 'DDD' from f00;
HQC key=SELECT #? || #? FROM F00 ;
Found in HQC:
SQL query=select CONCAT('AAA', 'BBB') from f00;
HQC key=SELECT CONCAT ( 'AAA' , 'BBB' ) FROM F00 ;

HQC backpatch OK:
SQL query=select CONCAT('AAA', 'BBB') from f00;
HQC key=SELECT CONCAT ( 'AAA' , 'BBB' ) FROM F00 ;

HQC::AddEntry():
SQL query=select CONCAT('EEE', 'FFF') from f00;
HQC key=SELECT CONCAT ( 'EEE' , 'FFF' ) FROM F00 ;

[taoufik ben abdellatif (taoufik-abdellatif)]

there are two supported syntax variations for the concat string function. CONCAT: this form is supported and cacheable. "||" : this form is not supported and renders the query not cacheable. Changes have been committed.