URI | http://purl.tuc.gr/dl/dias/FA5231DA-D168-4CB2-AA1A-FDAF32CF9E93 | - |
Αναγνωριστικό | https://doi.org/10.1016/0306-4379(84)90017-6 | - |
Γλώσσα | en | - |
Τίτλος | Estimating block selectivities | en |
Δημιουργός | Christodoulakis Stavros | en |
Δημιουργός | Χριστοδουλακης Σταυρος | el |
Εκδότης | Elsevier | en |
Περίληψη | In many data base performance studies there is a need to estimate the number of records of a file which qualify in a query, as well as the number of blocks of secondary storage which contain these records. In this paper we present a model of data base contents and data placement on devices. We extend a multivariate statistical model that was used for the estimation of record selectivities in [5] to model the distribution of records that qualify in a query among the blocks of secondary storage. Then we show how to obtain estimates of block selectivities and we compare our estimates with the estimates of previous models. | en |
Τύπος | Peer-Reviewed Journal Publication | en |
Τύπος | Δημοσίευση σε Περιοδικό με Κριτές | el |
Άδεια Χρήσης | http://creativecommons.org/licenses/by/4.0/ | en |
Ημερομηνία | 2015-11-25 | - |
Ημερομηνία Δημοσίευσης | 1984 | - |
Θεματική Κατηγορία | Information Systems | en |
Βιβλιογραφική Αναφορά | S. Christodoulakis, "Estimating block selectivities", Information Systems, vol. 9, no. 1, pp. 69-79, 1984. doi: 10.1016/0306-4379(84)90017-6 | en |