DB2 v10.5 Fixpack 2 has just been released. There is one bit of the changes as described in the fixpack summary that got my attention:
"The performance of a select, update, or delete operation that affects only one row in a column-organized table can be improved if the table has unique indexes, because the query optimizer can now use an index scan instead of a full table scan. "
As I wrote about the "Oraganize By Column" about 2 months ago, I thought it was unfortunate that DB2 was unable to use the primary key index to locate a single row. Naturally what this fixpack has promised to deliver is encouraging.
Unfortunately, after applying this fixpack and redoing the test, I am still not able to get the index scan to work for a ridiculously senseless and simple query like "SELECT C1 FROM T1 WHERE C1 = 10", where C1 is the primary key, with T1 holding 1 million rows.
More bugs? Installation problem? Blah ...
"The performance of a select, update, or delete operation that affects only one row in a column-organized table can be improved if the table has unique indexes, because the query optimizer can now use an index scan instead of a full table scan. "
As I wrote about the "Oraganize By Column" about 2 months ago, I thought it was unfortunate that DB2 was unable to use the primary key index to locate a single row. Naturally what this fixpack has promised to deliver is encouraging.
Unfortunately, after applying this fixpack and redoing the test, I am still not able to get the index scan to work for a ridiculously senseless and simple query like "SELECT C1 FROM T1 WHERE C1 = 10", where C1 is the primary key, with T1 holding 1 million rows.
More bugs? Installation problem? Blah ...
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