pkarklin: мне кажется,чт аналог этих опций есть в мсскл, дам вам только выдержку из док:
У SqlAnywhere как на уровне всей базы так и на уровне конкретного запроса в числе хинтов есть такие опции как:
optimization_workload option
http://infocenter.sybase.com/help/index.jsp?docset=/com.sybase.help.sqlanywhere.12.0.1/sqlanywhere_en12/help_top_index.htm&docSetID=1744
Determines whether query processing is optimized towards a workload that is a mix of updates and reads or a workload that is predominantly read-based.
The optimization_workload option controls whether SQL Anywhere optimizes queries for a workload that is a mix of updates and reads or predominantly read only.
If the option is set to Mixed (the default), SQL Anywhere chooses query optimization algorithms appropriate for a workload that is a mixture of short inserts, updates, and deletes and longer running read-only queries.
If the option is set to OLAP , SQL Anywhere chooses algorithms appropriate for a workload that consists for the most part of long-running queries, combined with batch updates.
In particular, the optimizer may choose to use the Clustered Hash Group By query execution algorithm.
When the option is set to OLAP, the Clustered Hash Group By algorithm is enabled. If the option is set to Mixed (the default), it is disabled.
optimization_level option
Controls the amount of effort made by the SQL Anywhere query optimizer to find an access plan for a SQL statement.
optimization_goal option
Determines whether query processing is optimized towards returning the first row quickly, or minimizing the cost of returning the complete result set.
The optimization_goal option controls whether SQL Anywhere optimizes SQL data manipulation language (DML) statements for response time or total resource consumption.
If the
option is set to All-rows (the default) , then SQL Anywhere optimizes a query to choose an access plan with the minimal estimated total retrieval time. Setting
optimization_goal to All-rows may be appropriate for applications that intend to process the entire result set, such as Sybase PowerBuilder DataWindow applications. A setting of All-rows is also appropriate for insensitive (ODBC static) cursors since the entire result is materialized when the cursor is opened. It may also be appropriate for scroll (ODBC keyset-driven) cursors, since the intent of such a cursor is to permit scrolling through the result set.
If the option is set to
First-row , SQL Anywhere chooses an access plan that is intended to reduce the time to fetch the first row of the query's result, possibly at the expense of total retrieval time.
In particular, the SQL Anywhere optimizer will typically avoid, if possible, access plans that require the materialization of results to reduce the time to return the first row . With this setting, the optimizer favors access plans that utilize an index to satisfy a query's ORDER BY clause, rather than plans that require an explicit sorting operation.
