5 commits

Author	SHA1	Message	Date
Sergei Petrunia	85cc831880	MDEV-31067: selectivity_from_histogram >1.0 for a DOUBLE_PREC_HB histogram ... Variant #2. When Histogram::point_selectivity() sees that the point value of interest falls into one bucket, it tries to guess whether the bucket has many different (unpopular) values or a few popular values. (The number of rows is fixed, as it's a Height-balanced histogram). The basis for this guess is the "width" of the value range the bucket covers. Buckets covering wider value ranges are assumed to contain values with proportionally lower frequencies. This is just a [brave] guesswork. For a very narrow bucket, it may produce an estimate that's larger than total #rows in the bucket or even in the whole table. Remove the guesswork and replace it with basic logic: return either the per-table average selectivity of col=const, or selectivity of one bucket, whichever is lower.	2023-04-28 22:39:25 +03:00
Oleksandr Byelkin	7841a7eb09	Merge branch '10.3' into 10.4	2021-07-31 22:59:58 +02:00
Sergei Golubchik	6190a02f35	Merge branch '10.2' into 10.3	2021-07-21 20:11:07 +02:00
Igor Babaev	658128af43	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 8d5a11122c. 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.	2019-02-03 14:56:12 -08:00
Michael Widenius	a7abddeffa	Create 'main' test directory and move 't' and 'r' there	2018-03-29 13:59:44 +03:00

Renamed from mysql-test/r/selectivity_no_engine.result (Browse further)