H. Wedekind. On the selection of access paths in a data base system. In J. W. Klimbie and K. L. Koffeman, editors, Data Base Management, pages 385--397. NorthHolland, Amsterdam, 1974.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....node are accounted for by entries in a node; there is one entry per child. The entries contain key and pointer information. The leaf nodes contain the items in the B tree, where an item consists of a key and a pointer to the associated record (This type of B tree was first proposed by Wedekind [17] and is often called a B tree) A B tree node is of order k if it has k entries or items. This analysis will count the entries in the interior nodes because analyses of interior nodes will be primarily concerned with their fanout. The analysis will count the items in the leaf nodes because we ....

H. Wedekind. On the selection of access paths in a data base system. In J.W. Klimbie and K.L. Koffeman, editors, Database Management, pages 385--397. North Holland Publishing Company, 1974.

....the operation and then rebalances the tree if necessary. An updater is referred to as an updating reader and an updating writer while in searching and restructuring phase respectively. The path from the root to a leaf determined by a process on its passage to a leaf is referred to its access path [Wedekind74]. In order to regulate concurrent accessses we need a concurrency control mechanism to specify the types of locks to be used and a compatibility and convertibility graph (CCG) for them [Samadi76] Bayer77] Kwong82] Processes can manipulate the locks via three types of indivisible operations, ....

H Wedekind, On the selection of access paths in a data base system (J W Klimbie, K L Koffeman, eds.), Database management, pp. 385 - 397, Amsterdam: North-Holland 1974.

....e i e 10 5 7 1 8 3 r f h n o Index on C linked leaf pages Index on A Index on B Tab e g z e g Figure 2. Example for a relation R with 3 indices B,andCand three indices I A , I B,a ndI C on these attributes. As mentioned earlier, we assume that all indices are B trees [23] in which all # key, RID # entries are in the leaf pages. The inner nodes of the B tree contain only reference keys for navigation purposes no real data values. Furthermore, we assume a B link tree organization [10] in a B link tree, the leaf nodes are chained in order to facilitate ....

H. Wedekind. On the selection of access paths in a data base system. In IFIP Working Conference Data Base Management, pages 385--398, 1974.

....The buffer manager also coordinates the writing of pages to disk with the log manager and the recovery manager. That is, it supports the write ahead logging rule and the force log at commit rule. 2. 5 The B tree The B tree was introduced in [2] The B tree was introduced by Wedekind in [43]. It is one of the most commonly used access methods in database management systems today. It is a balanced tree where the distance between the root and any leaf is the same. Figure 3 shows a picture of a B tree. Each node in the B tree corresponds to a disk page. In the following ....

....and recovery problem associated with it. Section 7.8 describes related results. Section 7.9 contains a summary and a discussion of future work. Alternative concurrency protocols for some of the leaf operations are in appendix A. 7. 2 The Problem The B tree was introduced by Wedekind in [43]. It is a balanced tree where the distance between the root and any leaf is the same. The B tree in this context is sparsely populated, CHAPTER 7. ON LINE REORGANIZATION OF B TREES 109 that is, a large portion of many leaf pages is unused. There are also some free pages available in the ....

H. Wedekind. On the selection of access paths in a data base system, chapter Database Management. North Holland Publishing Company, 1974.

....node are accounted for by entries in a node; there is one entry per child. The entries contain key and pointer information. The leaf nodes contain the items in the B tree, where an item consists of a key and a pointer to the associated record (This type of B tree was first proposed by Wedekind [17] and is often called a B tree) A B tree node is of order k if it has k entries or items. This analysis will count the entries in the interior nodes because analyses of interior nodes will be primarily concerned with their fanout. The analysis will count the items in the leaf nodes because we ....

H. Wedekind. On the selection of access paths in a data base system. In J.W. Klimbie and K.L. Koffeman, editors, Database Management, pages 385--397. North Holland Publishing Company, 1974.

....key that is stored in a leaf and is larger than K. If the leaf node becomes too small (contains m=2 Gamma 1 keys) merge it with one of its siblings. If the sibling has m=2 keys, merge the node and its sibling and add the separator key from the parent, to form a node with m keys. Wedekind [87] defines a variant of a B tree, which he calls a B tree. The primary difference between a B tree and a B tree is that in a B tree, all data is stored at the leaves. Some other changes are necessary, primarily that all operations must operate on the leaves, and pointer p j in an ....

....node are accounted for by entries in a node; there is one entry per child. The entries contain key and pointer information. The leaf nodes contain the items in the B tree, where an item consists of a key and a pointer to the associated record (This type of B tree was first proposed by Wedekind [87]) A B tree node is of order k if it has k entries. This analysis will count the entries in the interior nodes because analyses of interior nodes will be primarily concerned with their fanout. The analysis will count the items in the leaf nodes because we assume that the keys are stored in the ....

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H. Wedekind. On the selection of access paths in a data base system. In J.W. Klimbie and K.L. Koffeman, editors, Database Management, pages 385--397. North Holland Publishing Company, 1974.

....still be proportional to the height of the tree, though. The paper [62] introduces an implementation, where at any time only a constant number of locks have to be hold for any single update. The structure which is used is called a B link tree. This is only a slight modification of B # trees [88], where links to the sibling to the right are maintained. Still, overflow is taken care of by the inserting process. As only a constant number of locks are used, a complicated scheme with process queues has to be designed to ensure that the process can traverse the path from the leaf to the root ....

H. Wedekind. On the Selection of Access Paths in a Data Base System. In J. W. Klimbie and K. L. Ko#eman, editors, Data Base Management, pages 385-397. North-Holland, 1974.

....on search trees that deals with the idea of uncoupling the updating from the rebalancing. At first, this was only done partially, but later the separation became complete. The more important results introducing the idea of separating updating and rebalancing and partially obtaining this include [8, 13, 14, 15, 19, 26, 27, 28]. In [21, 22] rebalancing is separated entirely from the updating. States of unbalance are merely registered, and background processes deal with these problems of unbalance in parallel with searches and updates. This type of search tree is referred to as a search tree with relaxed balance. ....

H. Wedekind. On the Selection of Access Paths in a Data Base System. In J. W. Klimbie and K. L. Koffeman, editors, Data Base Management, pages 385--397. North-Holland, 1974.

....on search trees that deals with the idea of uncoupling the updating from the rebalancing. At first, this was only done partially, but later the separation became complete. The more important results introducing the idea of separating updating and rebalancing and partially obtaining this include [9, 14, 15, 16, 19, 24, 25, 26]. In [21, 22] the rebalancing is separated entirely from the updating. Several complexity results have been obtained for relaxed search trees. The analysis of the behavior of a relaxed version of AVL trees [1] introduced in [22] was given in [17] The structure chromatic search tree of interest ....

H. Wedekind. On the Selection of Access Paths in a Data Base System. In J. W. Klimbie and K. L. Koffeman, editors, Data Base Management, pages 385--397. North-Holland, 1974.

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H. Wedekind. On the selection of access paths in a data base system. In J. W. Klimbie and K. L. Koffeman, editors, Data Base Management, pages 385--397. NorthHolland, Amsterdam, 1974.

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H. Wedekind, On the selection of access paths in a data base system, in IFIP Working Conference on Data Base Management" (J. W. Klimbie and K. L. Koffeman, Eds.), pp. 385#397, North-Holland, Amsterdam#New York, 1974.

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H. Wedekind. On the selection of access paths in a database system. In Proceedings of the IFIP Working Conference on Data Base Management. North{Holland Publishing Company, 1974.

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H. Wedekind. On the selection of access paths in a database system. In Proceedings of the IFIP Working Conference on Data Base Management. North{Holland Publishing Company, 1974.

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