Sybase IQ uses Component Integration Services (CIS) to query tables on remote servers. Changes in Sybase IQ 15.2 allow queries with proxy tables or SA IN SYSTEM tables to execute faster than earlier versions, when the number of rows returned from an IN SYSTEM or proxy table is small compared to the number of rows returned from Sybase IQ.
Queries that benefit from these changes include:
SELECT, SELECT INTO, or INSERT…SELECT statements only
A statement that contains one or more Sybase IQ tables and one or more proxy or SA IN SYSTEM tables
Queries that do not benefit from these changes include:
References to system catalog tables
A subquery in a CASE expression
LOBs (columns of LONGBINARY, LONGVARCHAR, LONGNVARCHAR, LONGBITSTRING, or XML) on remote tables
A function not supported by target node (for example, bit_or or user defined functions)
Queries with global variables