Inverted index structures are a core element of current text retrieval systems. They can be constructed quickly using offline approaches, in which one or more passes are made over a static set of input data, and, at the completion of the process, an ...

The packed-memory array (PMA) is a data structure that maintains a dynamic set of N elements in sorted order in a Θ(N)-sized array. The idea is to intersperse Θ(N) empty spaces or gaps among the elements so that only a small number of elements need to ...

We present a scalable distributed data structure called LH*. LH* generalizes Linear Hashing (LH) to distributed RAM and disk files. An LH* file can be created from records with primary keys, or objects with OIDs, provided by any number of distributed and ...

Access methods based on signature files can largely benefit from possibilities offered by parallel environments. To this end, an effective declustering strategy that would distribute signatures over a set of parallel independent disks has to be combined ...

We present an exact performance analysis, under random insertions, of file organizations that use multibucket data leaves and perform partial expansions before splitting. We evaluate the expected disk space utilization of the file and show how the ...

The problem of disk allocation addresses the issue of how to distribute a file on several disks in order to maximize concurrent disk accesses in response to a partial match query. In this paper a coding-theoretic analysis of this problem is presented, ...

Gral is an extensible database system, based on the formal concept of a many-sorted relational algebra. Many-sorted algebra is used to define any application's query language, its query execution language, and its optimiztion rules. In this paper we ...

We present a dynamic external hash method that allows retrieval of a record by only one access to mass storage while maintaining a high load factor. The hash function is based on generalized spiral storage. Both primary and overflow records are allocated ...

A new multiattribute index structure called the hB-tree is introduced. It is derived from the K-D-B-tree of Robinson [15] but has additional desirable properties. The hB-tree internode search and growth processes are precisely analogous to the ...

A direct and unified approach is used to analyze the efficiency of batched searching of sequential and tree-structured files. The analysis is applicable to arbitrary search distributions, and closed-form expressions are obtained for the expected batched ...

Indexes are commonly employed to retrieve a portion of a file or to retrieve its records in a particular order. An accurate performance model of indexes is essential to the design, analysis, and tuning of file management and database systems, and ...

Perfect hashing refers to hashing with no overflows. We propose and analyze a composite perfect hashing scheme for large external files. The scheme guarantees retrieval of any record in a single disk access. Insertions and deletions are simple, and the ...

We develop an efficient approach to Trie index optimization. A Trie is a data structure used to index a file having a set of attributes as record identifiers. In the proposed methodology, a file is horizontally partitioned into subsets of records using a ...

A bounded-disorder (BD) file is one in which data are organized into nodes that are indexed, e.g., by means of a B-tree. The data nodes are multibucket nodes that are accessed by hashing. In this paper we present two important improvements to the BD ...

A new dynamic hashing scheme is presented. Its most outstanding feature is that any record can be retrieved in exactly one disk access. This is achieved by using a small amount of supplemental internal storage that stores enough information to uniquely ...

Both single-level and two-level indexed descriptor schemes for multikey retrieval are presented and compared. The descriptors are formed using superimposed coding techniques and stored using a bit-inversion technique. A fast-batch insertion algorithm for ...

Signature files seem to be a promising access method for text and attributes. According to this method, the documents (or records) are stored sequentially in one file ("text file"), while abstractions of the documents ("signatures") are stored ...

In this paper we examine the problem of object and record retrieval from optical disks. General objects (such as images, documents, etc.) may be long and their length may have high variance. We assume that all the components of an object are stored ...

Concurrent access to complex shared data structures, particularly structures useful as database indices, has long been of interest in the database community. In dynamic databases, tree structures such as B-trees have been used as indices because of their ...

The use of database systems for managerial decision making often incorporates information-retrieval capabilities with numeric report generation. Of great concern to the user of such a system is the response time associated with issuing a query to the ...