MDEV-16188 Use in-memory PK filters built from range index scans

This patch contains a full implementation of the optimization
that allows to use in-memory rowid / primary filters built for range  
conditions over indexes. In many cases usage of such filters reduce  
the number of disk seeks spent for fetching table rows.

In this implementation the choice of what possible filter to be applied  
(if any) is made purely on cost-based considerations.

This implementation re-achitectured the partial implementation of
the feature pushed by Galina Shalygina in the commit
8d5a11122c32f4d9eb87536886c6e893377bdd07.

Besides this patch contains a better implementation of the generic  
handler function handler::multi_range_read_info_const() that
takes into account gaps between ranges when calculating the cost of
range index scans. It also contains some corrections of the
implementation of the handler function records_in_range() for MyISAM.

This patch supports the feature for InnoDB and MyISAM.

1 files changed, 4 insertions, 0 deletions

diff --git a/mysql-test/main/subselect_mat_cost.test b/mysql-test/main/subselect_mat_cost.test
index 5a1fb550ca4..5f44d0d2bf4 100644
--- a/mysql-test/main/subselect_mat_cost.test
+++ b/mysql-test/main/subselect_mat_cost.test
@@ -205,6 +205,9 @@ WHERE Code NOT IN (SELECT Country FROM CountryLanguage WHERE Language = 'English
 -- echo Countries that speak French OR Spanish, but do not speak English
 -- echo MATERIALIZATION because the outer query filters less rows than Q5-a,
 -- echo so there are more lookups.
+
+
+set statement optimizer_switch='rowid_filter=off' for
 EXPLAIN
 SELECT Country.Name
 FROM Country, CountryLanguage 
@@ -212,6 +215,7 @@ WHERE Code NOT IN (SELECT Country FROM CountryLanguage WHERE Language = 'English
   AND (CountryLanguage.Language = 'French' OR CountryLanguage.Language = 'Spanish')
   AND Code = Country;
 
+set statement optimizer_switch='rowid_filter=off' for
 SELECT Country.Name
 FROM Country, CountryLanguage 
 WHERE Code NOT IN (SELECT Country FROM CountryLanguage WHERE Language = 'English')