JPH04286072A - High speed retrieval system for table - Google Patents

Abstract

PURPOSE:To supply a high speed retrieval system for table, which can retrieve the small number of table retrieval times, when the number of tables to be retrieved becomes considerably large. CONSTITUTION:A hash 1 decision means 14 deciding a hash value, a hash 2 decision means 15 deciding the hash value different from that of the hash 1 decision means 14, and a table reconstitution means 12 reconstructing a table group 2 are provided. When there are many equal value chains for the table of a constitution element unit from a hash table, the different hash table is newly pointed from the above hash table and the table of said constitution element unit is incorporated to the table reconstitution means with a value decided in the above hash 2 decision means 15 from the different hash table.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-speed search method for tables in large-scale computer systems.

0002

[Prior Art] Conventionally, this type of high-speed table search method was
There were mainly two methods described below. Two methods were used: a method of searching a table using a hash table, and a method of performing a binary search by arranging component names in ascending (or descending) order.

0003

[Problems to be Solved by the Invention] In the conventional high-speed table search method described above, when the number of constituent elements becomes very large (for example, tens of thousands or more), when using the hash method, the size of the hash table becomes large. Even if it is possible to handle hundreds to thousands of elements, the average number of equivalent chains is 10 to 100 or more, so an average of 10 or more table searches is required, or when using the binary search method. Since the search is performed in two parts, it is necessary to search the table more than ten times on average, and the problem is that the table cannot be searched immediately.

0004

[Means for Solving the Problems] The terminal address determining means of the present invention includes a hash 1 determining means for returning a hash value in a table group in which a hash table points to a table for each component, and a hash 1 determining means for returning a hash value. hash 2 determining means for returning a hash value different from the means; table creating means for incorporating the hash table into a table for each component so as to point to the value determined by the hash 1 determining means from the hash table; If there are many equivalence chains from the hash table to the component-based table, point the hash table to another new hash table, and use the value determined by the hash 2 determining means from the other hash table. a table reconfiguration means for incorporating the table in units of constituent elements so as to point to the table; and a table search means for searching for a target table in units of constituent elements using the hash 1 determining means and the hash 2 determining means; A feature is that a table to be searched can be searched with a small number of table searches.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention, which includes table creation means 11 for creating table group 2 to be described later, table reconfiguration means 12 for reconfiguring table group 2, and table group 2. table search means 13 for searching 2, and hash 1 determining means 1 for determining the hash value.
4, hash 2 determining means 15 which determines a hash value different from hash 1 determining means 14, and table group 2. FIG. 2 shows the contents of the table group 2 of the present invention, including a route table 21, a hash table 22, and a hash table 2 sorted by hash values determined by the hash 1 determining means 14 from the route table 21.
2, the sub-hash table 2 is sorted by the hash value determined by the hash table determining means 15.
3. It is composed of a resource table 24, a resource table 25, a resource table 26, and a resource table 27 that hold information for each component.

The feature of the present invention is that, as shown in the figure, table reconfiguration means 12, hash 2 determination means 15, and subhash table 23 are provided.

Next, the operation of this embodiment will be explained below.

[0009] Each table has an identifier at the top of the table indicating what type of table it is. This structure provides a structure in which it is easy to distinguish whether the table pointed to by the pointer is a resource table or a hash table/subhash table.

When the table creation means 11 newly registers a table for each component in the table group 2, it obtains the address of the hash table 22 pointed to by the pointer from the route table 21. The hash values in the hash table 22 are distributed according to the values determined by the hash 1 determining means 14.

Assume that when the hash value is determined by the hash 1 determination means 14 in order to newly register the resource table 27, the hash value is entry 2. At this time, entry 2
If the resource table 26 is already chained in the resource table 26, the resource table 27 is
Pointed to by the equivalence chain pointer inside.

Next, when attempting to newly register the resource table 25, it is assumed that when the hash value is determined by the hash 1 determining means 14, entry 1 is found. At this time, if the entry 1 already has many equivalence chains including the resource table 24, the table creation means 11 chains the resource table 25 to the last table of the equivalence chain, and adds the entry 1 to the table reconfiguration means 12.
Pass the value of

The table reconfiguration means 12 now secures a subhash table 23 different from the hash table 22, and changes the hash table 22 so that the subhash table 23 is pointed to by the entry 1. Then, the resource table previously pointed to by entry 1 is changed to point to the subhash table 23 in accordance with the hash value obtained using the hash 2 determining means 15 while tracing the equivalence chain.

[0014] Here, in the hash table 22, there is an equivalence chain, and the resource tables 24 and 25 have different hash functions, so entry 1 of the sub-hash table is in the resource table 24, and entry 2 is in the resource table 24. Table 25, and so on, the table equivalence chain is resolved.

The table search means 13 for searching these tables searches for a target resource table while determining the table identifier assigned to each table.

For example, when it is desired to search the resource table 25, the subhash table 23 is reached from the hash table 22 using the entry 1 obtained by the hash 1 determining means 14. Here, since the identifier of the subhash table 23 indicates a subhash table, the table search means 13 recognizes that this table is a subhash table, and returns a hash value different from that of the hash 1 determination means 14. 2 determination means 15 is used to obtain entry 2 of the subhash table.

[0017] Then, the resource table 25 pointed to by this entry can be reached.

As described above, according to this embodiment, even if there are many equivalence chains of hash tables, by using a subhash table, searching for a resource table can be shortened without tracing previous equivalence chains. This can be done within a short period of time and the number of accesses.

Furthermore, if there is no equivalence chain of the hash table, there is no table reconfiguration means 12, and the table creation means 11 hash table 2 from the beginning.
The only difference is that table group 2 is created so that subhash table 23 is pointed to subhash table 2.

[0020]

[Effect of the Invention] As explained above, the present invention uses a hash table in two stages when the number of constituent elements becomes very large (for example, tens of thousands or more). If there is no chain, the table to be searched can be found with two table searches, which has the effect of significantly reducing the overhead of computer table searches.

[0021]

[Detailed explanation of drawings]

[0022]

FIG. 1 is a block diagram of an embodiment of the invention.

[0023]

FIG. 2 is a diagram showing an example of the contents of table group 2 in FIG. 1;

[0024]

[Explanation of symbols]

11 Table creation means 12 Table reconfiguration means 13 Table search means 14 Hash 1 determining means 15 Hash 2 determining means 2 Table group 21 Route table 22 Hash table 23 Subhash table

Claims (2)

[Claims] 1. A hash 1 determining means for returning a hash value in a table group in which a hash table points to a table for each constituent element, and a hash 2 determining means for returning a hash value different from the hash 1 determining means.
determining means, and determining the hash 1 from the hash table.
The value determined by the determining means points to another hash table, and the hash 2 is retrieved from the another hash table.
Searching for a target table for each component using a table creation means that points to the table for each component with the value determined by the determination means, and the hash 1 determination means and the hash 2 determination means. A high-speed table search method is provided with a table search means, and is characterized in that a table to be searched can be searched with a small number of table searches. 2. Hash 1 determining means for returning a hash value, and hash 2 determining means for returning a hash value different from the hash 1 determining means in a table group in which a hash table points to a table for each constituent element.
determining means, and determining the hash 1 from the hash table.
A table creation means that incorporates the value determined by the determination means to point to the table for each component, and when there are many equivalence chains from the hash table to the table for each component, table reconfiguration means that points to another hash table and incorporates a value determined by the hash 2 determination means from the other hash table to the table for each constituent element, the hash 1 determination means; 1. A high-speed table search method, characterized in that a table search means for searching a target table in units of constituent elements using a hash 2 determination means is provided, and a table to be searched can be searched with a small number of table searches.