CA2562281C - Partial query caching - Google Patents

Partial query caching

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Publication number
CA2562281C
CA2562281C CA 2562281 CA2562281A CA2562281C CA 2562281 C CA2562281 C CA 2562281C CA 2562281 CA2562281 CA 2562281 CA 2562281 A CA2562281 A CA 2562281A CA 2562281 C CA2562281 C CA 2562281C
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Prior art keywords
plan
results set
operator
plurality
plan operator
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CA 2562281
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French (fr)
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CA2562281A1 (en )
Inventor
Cetin Ozbutun
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Oracle International Corp
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Oracle International Corp
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    • GPHYSICS
    • G06COMPUTING; CALCULATING; COUNTING
    • G06FELECTRIC DIGITAL DATA PROCESSING
    • G06F17/00Digital computing or data processing equipment or methods, specially adapted for specific functions
    • G06F17/30Information retrieval; Database structures therefor ; File system structures therefor
    • G06F17/30286Information retrieval; Database structures therefor ; File system structures therefor in structured data stores
    • G06F17/30386Retrieval requests
    • G06F17/30424Query processing
    • G06F17/30442Query optimisation
    • G06F17/30448Query rewriting and transformation
    • G06F17/30457Query rewriting and transformation to use cached/materialised query results
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10STECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S707/00Data processing: database and file management or data structures
    • Y10S707/99931Database or file accessing
    • Y10S707/99933Query processing, i.e. searching

Abstract

When a query is performed an execution plan is formed, which is made up of a plurality of plan operators. Before executing any given plan operator, a storage area is checked. If a results set has been stored corresponding to the plan operator, then the cached results set is used instead of the executing the plan operator. If no results set exists that corresponds to the particular plan operator, the plan operator is executed, and the results set that is output may be stored for use by another plan operator of another execution plan.

Description

PARTIAL QUERY CACHING
FIELD OF THE INVENTION
[0001] The present invention relates to processing database commands, and in particular to caching results sets of queries.

BACKGROUND OF THE INVENTION

[0002] The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued.
Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section.
Similarly, the problems identified with an approach should not be assumed to have been recognized in the prior art, unless otherwise indicated.

[0003] When a database server receives a statement representing a request to perform a database operation, the database server may generate an execution plan. An execution plan defines the steps and operations performed by a database server to carry out a request. The statement used to request database operations may be in the form of a database command that conforms to a database language, such as Structured Query Language (SQL).

[0004] It is desirable to return results sets of queries quickly. As more and more people use databases to get information they are looking for, there is increased likelihood that some of the queries issued against a database are the same. In some systems, results sets of at least certain queries are stored. When a query is received a text based search is performed to find the previously executed query. If it is found that the same identical query (having the same text) is being presented for a second time, and if the results set for that query was stored, the system returns the cached results set rather than performing the query a second time. The more people that use the database, the greater the performance enhancement gained by saving the results sets of queries.

[0005] However, many queries are not identical, but similar. Many queries may process subsets of identical data within their results sets. Nonetheless, because the queries are not identical, a cached results set that is likely to have identical subsets of data as the expected results set cannot be reused, despite the similarity of the results sets, and each of the similar queries are executed.

[0006] Based on the forgoing, there is still a need to store and reuse results sets of queries.

BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The present invention is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar elements and in which:

[0008] FIG. 1 is an execution plan diagram.

[0009] FIG. 2 is a flowchart showing a method of executing an plan operator, according to an embodiment of the invention.

[0010] FIG. 3 is a flow chart showing a method of storing a results set, according to an embodiment of the invention.

[0011] FIG. 4 is a block diagram that illustrates a computer system upon which an embodiment of the present invention may be implemented.

DETAILED DESCRIPTION OF THE INVENTION

[0012] A method and apparatus for partial query caching is described. In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, that the present invention may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to avoid unnecessarily obscuring the present invention.

[0013] Several features are described hereafter that can each be used independently of one another or with any combination of the other features. However, any individual feature may not address any of the problems discussed above or may only address one of the problems discussed above. Some of the problems discussed above may not be fully addressed by any of the features described herein. Although headings are provided, information related to a particular heading, but not found in the section having that heading, may also be found elsewhere in the specification.

[0014] Described herein are approaches that use at least a portion of the results previously generated for a query for a subsequent computation of another query. A results set generated for an operation defined by the execution plan of a query is used as the results set for an identical or similar operation of an execution of another query.

EXECUTION PLANS

[0015] Database servers generate execution plans that are optimized for efficiency. When determining what steps to include in an execution plan, and the order in which the steps are performed, a database server accounts for many factors that affect efficiency.
For example, a query may request rows that contain a first value in a first column and a second value in a second column.
If the first column is indexed, then a database server may generate an execution plan that uses the index to access data more efficiently. Such an execution plan may include the following steps, executed in the order indicated below.
1. Access the index and generate row IDs of rows that contain the first value in the first column.
2. Obtain the set of rows identified by the row IDs.
3. Filter the set of rows for the second value in the second column.

[0016] A query execution plan comprises steps referred to as "plan operators".
A plan operator defines a set of operations that are performed in an execution plan and that may be executed by a database server to access one or more row sources. A row source may be data stored in a database (e.g., one or more rows in a table), or one or more output rows of another plan operator.
Execution plans are explained in chapter 22 - 24 of Oracle 8i Concepts, by Oracle Corporation, February, 1999.

ILLUSTRATIVE EXECUTION PLAN DIAGRAM

[0017] An execution plan can be represented by an execution plan diagram. FIG.
1 is an execution plan diagram provided to illustrate various features of an example of an execution plan that includes partial query caching. In FIG. 1, execution plan 102 is generated for query 104 (by the database server). Query 104 is the query SELECT tl.col4, t2.co12 FROM tl, t2 WHERE tl.collrt2.col2 AND tl.col3=192 GROUP BY tl.col4;

[0018] Query 104 contains predicate 105, which is tl.coll-t2.col2 and tl.co13=192. A
predicate is a logical expression that defines criteria that must be satisfied by the rows in the tables against which a query is applied.

[00191 In execution plan 102, plan operators are depicted using blocks.
Specifically, group plan operator 106, join plan operator 108, scan table and filter plan operator 112, and scan table plan operator 116 are the plan operators that make up execution plan 102.
Branches between a parent plan operator and a child plan operator represent a flow of rows from the child plan operator to the parent plan operator. Thus, the output rows of a child plan operator are input rows to a parent plan operator. Plan operators are described herein as performing the operations that the plan operators themselves define. However, this is simply a convenient way of expressing that a database server is performing the operations defined by the plan operators when the database server executes the plan operators.
[00201 In execution plan 102, scan table and filter plan operator 112 and scan table plan operator 116 perform a scan of column coll of table tl and of column colt of table t2, respectively.
However, scan table and filter plan operator 112 additionally filters the scanned rows of table tl so that only rows having col3=192 are selected and thereby included in the output of scan table and filter plan operator 112. Join plan operator 108 joins the rows that are output from scan table and filter plan operator 112 and scan table plan operator 116 to form the rows that are output by join plan operator 108. Group plan operator 106 groups the rows created by join plan operator 108 into groups. As a result of group plan operator 106, each row in the output represents a different group (in other words, each t1.col4 in the output is unique).

FUNCTIONAL OVERVIEW
[0021] In partial query caching, the results sets of individual plan operators of query are computed and stored in a storage area for potential reuse for other queries.
The storage area is an operator output storage area, which will be referred to as output storage. The results sets of the plan operator are referred to herein as cached results sets. Each cached results set will have a signature generated based on the definition of the results set's respective plan operator. Plan operators with identical or similar definitions, and hence potentially identical or similar results sets, will have the same or similar signatures. To compute (i.e., generate results for) a plan operator, a signature is generated for the plan operator, and is used to search a storage area for a cached results set with the same signature. If a cached results set is found, the cached results set's plan operator may be further examined to determine whether the cached results set may be used as the results set for the plan operator being computed. In an another embodiment, if a cached results set for a given signature is found, the plan operator is not further examined, and the cached results set is used as the results set of the plan operator. If a cached results set is not found, then the plan operator is executed.
Additionally, the results set that was generated by executing the plan operator may be stored in the output storage for later use by another corresponding plan operator.
[0022] In an embodiment, first a search is performed for the entire query by searching for a results set of a plan operator that encompasses all of the plan operators of the execution plan of the query. If a results set was not stored for a plan operator corresponding to the entire query, then for one or more of the plan operators that make up the execution plan, the output storage is searched to see if cached results sets were stored for the corresponding plan operators.
[0023] In an embodiment, the plan operators are searched for, starting with those plan operators that encompass the largest portions of the search (e.g., a plan operator that encompasses the entire query), and preceding to searching for the plan operators that encompass next largest portions of the search, which are encompassed within the plan operators of the largest portions of the query. In other words, if cached results set are not found for a parent plan operator, a search is performed for cached results sets for the plan operators that are the immediate children of the parent plan operator, if any exist.

EXECUTING A QUERY
[0024] FIG. 2 is a flowchart showing a method 200 of executing a plan operator, according to an embodiment of the invention. Method 200 shows steps performed when executing a plan operator. In step 201, a plan operator is generated for a query. In step 202, a signature of the plan operator is generated. In step 204, a results set is generated by executing the plan operator. In step 206, the results set, generated in step 204, is stored in the output storage (e.g., cached). The output storage is discussed further below. In step 208, the signature and optionally the plan operator are stored in a manner in which the signature and optionally the plan operator are associated with the cached results set.
[0025] FIG. 3 is a flow chart showing a method 300 of utilizing cached results sets, according to an embodiment of the invention. In step 302 a plan operator is generated for a query.
In step 303, a signature is generated for plan operator that is being evaluated. In step 304, the output storage is searched for cached results set. In performing the search, a comparison may be performed between the signature of the plan operator that is being evaluated and the signatures stored in association with the cached results sets. In an embodiment, an exact match may not be required. In optional step 306, if a match is found, a further evaluation is performed in which the stored plan operator is compared to the plan operator being evaluated to see if the cached results set may be used. In step 308, if step 306 is included in the method 300, then if in step 306 it is determined that the cached results set is usable, the cached results set is returned (either to the user as a results set or for use as input by another plan operator) in lieu of executing the plan operator.
In step 308, if step 306 is not included in method 300, then if in step 304 a match is found (e.g., if the two signatures are found to be sufficiently similar), the cached results set is returned in lieu of executing the plan operator.
[00261 Referring to FIG. 1, in carrying out method 300, upon receiving query 104, the database server formulates query plan 102. Then the database server checks the plan operator output storage area to see if cached results sets were stored for the plan operators that make up execution plan 102. Plan operators that constitute larger portions of the query are searched for first, because if results sets corresponding to the plan operators that make up the larger portions are found, there is no need to search for the plan operators that make up the smaller portions encompassed by the larger portions.
[00271 For example, in execution plan 102, first a search is done for a cached results set corresponding to group plan operator 106. If a results set is found, the results set found is returned to the user as the results set of query 104 rather than executing group plan operator 106 a second time. Additionally, there is no need to search for results sets for the remaining plan operators, because the remaining plan operators of execution plan 102 are encompassed within group plan operator 106.
[00281 However, if a cached results set corresponding to group plan operator 106 is not found, then the database server searches for a cached results set corresponding to join plan operator 108. If a cached results set is found that corresponds to join plan operator 108, then that cached results set is returned for use as input to group plan operator 106, and there is no need to execute the remaining operators of execution plan 102. After executing group plan operator 106 on the cached results set corresponding to join, plan operator 108, the results set of group plan operator 106 (based on the cached results set corresponding to join plan operator 108) is returned to the user as the results set of query 104. The results set of executing group plan operator 106 may be stored in the output storage in case another query includes group plan operator 106 or a similar plan operator.
[0029] If a cached results set is not found that corresponds to join plan operator 108, then the database server searches for cached results sets corresponding to scan table and filter plan operator 112 and scan table plan operator 116. If a cached results set is found that corresponds to scan table and filter plan operator 112, the cached results set is returned for use by join plan operator 108. If a cached results set is not found for scan table and filter plan operator 112, then the database server executes scan table and filter plan operator 112 and returns the results set of executing scan table and filter plan operator 112 for use by join plan operator 108. Additionally, the results sets of scan table and filter plan operator 112 may be stored for later use. Similarly, if a cached results set are found for scan table plan operator 116, the cached results set is returned for use by join plan operator 108. If a cached results set is not found for scan table plan operator 116, then the database server executes scan table plan operator 116 and returns the results set of executing scan table plan operator 116 for use by join plan operator 108.
Additionally, the results set of scan table plan operator 116 may be stored for later use. Join plan operator 108 is then executed on the results sets returned, whether the results sets returned originated from executing scan table and filter plan operator 112 and scan table plan operator 116, originated from finding the cached results sets corresponding to the scan table and filter plan operator 112 and scan table plan operator 116, or originated from finding cached results sets stored for one of, and performing the other of, scan table and filter plan operator 112 and scan table plan operator 116. Next group plan operator 106 is executed using the results set of join plan operator 108, and the results set of group plan operator 106 are returned to the user as the results set of query 104. As mentioned above, the results set of executing group plan operator 106 and/or join plan operator 108 may be stored in the plan operator output storage in case another query includes one of group plan operator 106 or join plan operator 108.
[0030] In an embodiment, the results set of a given operator may not necessarily be stored.
Instead, a cost benefit analysis may be performed to determine whether to store the results set of the given operator or whether to not store the results set and have the operator executed a second time if another query includes the same operator. Some of the factors that may be used in determining whether to store the results set of the given operator are the time and resources necessary for executing the operator and the amount of storage area available. For example, if the time required to execute the plan operator is less than the expected time required to search the output storage for the cached results set, the results set may not be stored. Similarly, if the storage area required to store the results set is greater than the available storage area in the output storage (either because the results set is so large or because the storage area is full or nearly, for example), the results set may also not be stored. In contrast, if the results set does not require much storage area or there is a large amount of storage area available, and the plan operator requires a great deal of time to execute, the results set may be stored. Other factors that may be used in determining whether to store results set of a newly executed plan operator, as will be apparent to those skilled in the art.
[0031] Two different queries may each be formulated by a different set of database statements, but may nonetheless have the same execution plan. For example, a first query may include a NATURAL join, while a second query may be the same as the first query except instead of using a NATURAL join the join key is explicitly named in a USING clause. By formulating an execution plan and searching for results sets of the execution plan, the results sets of one query may be returned as the results sets of another query even though the two queries are formed by different sets of database statements.
[0032] The output storage may be any sort of memory, such as those described below in the HARDWARE OVERVIEW. In an embodiment, the output storage is one or more storage areas in one or more temporary or short term storage devices (e.g., volatile storage devices). In an embodiment, the short term output storage may have relatively fast access time (e.g., flash memory or RAM) when compared to long term memory (e.g., a hard drive). In an embodiment, the output storage is one or more storage areas in one or more long term storage devices (e.g., non-volatile storage devices). In an embodiment, the output storage is a combination of one or more storage areas in one or more long term storage devices and short term storage devices.

SIGNATURES OF PLAN OPERATORS
[0033] In an embodiment, a signature is established for each plan operator based on the plan operator's definition. The signatures are generated such that plan operators with the same or similar definitions have the same signature. In an embodiment, the signature may be based on a data structure used to define or describe a plan operator. For example, the data structure associated with the plan operator may be used to generate a hash value, which may be mapped to numerical values that are used for forming a sequence numbers used to compose a signature.

[0034] The results set of a plan operator may be stored with the signature of the plan operator. When a new query is received, the results sets associated with previously executed plan operators are searched for by searching for a results set that is associated with a plan operator having the same signature. Using signatures, two queries may be written differently, but their respective execution plans may share plan operators with the same signature.
[0035] Use of the signatures allows the database server to quickly find results sets that may be used for a query. In an embodiment, each plan operator is mapped to signature that represents an exact description of that plan operator. In an alternative embodiment, each plan operator is mapped to a signature that is also used for a set and/or range of other plan operators, and the results set associated with this signature is used for each of the plan operators within the set and/or range of the signature. In this embodiment, the signature does not necessarily represent an exact description of the plan operator. In an embodiment, after finding a match of signatures the plan operators are compared in order to evaluate whether the results set from one plan operator are expected to be usable as the results set of the other plan operator. In another embodiment, if the two signatures are match or are sufficiently close the cached results set found is used without a further check of the plan operator that produced the cached results set.

PLAN OPERATORS THAT ARE SIMILAR BUT NOT IDENTICAL
[0036] Many times queries are similar but not identical. By searching for plan operators corresponding to queries that are not identical, the speed at which results sets may be returned for the query may be increased. Accordingly, in an embodiment, when searching for a results set of a plan operator, if a cached results set for a different plan operator is found that is similar, the results set of the similar operation may be used instead of executing the actual operation. For example, if a plan operator generated for a query involves finding a set of data associated with the dates November 1, 2000-January 1, 2004, and a cached results set is found for a plan operator that finds data associated with the dates November 1, 2000-February 23, 2004, the cached results set found may be used instead of executing the actual plan operator generated for the query. In one embodiment, the cached results set found is used "as is", without further modification. In another embodiment, the cached results set found is further filtered to remove some or all of the extra data in the cached results set. In another embodiment, the cached results set or the signature of the cached results set is evaluated to determine whether the user is likely to mind receiving the difference between the results requested and cached results set found, which in this example is the extra data associated with the dates Jan 2, 2004 through February 23, 2004. If it is expected that the user will not mind the difference, the cached results set found is returned rather than performing the plan operator. If it is expected that the user will mind the difference, the plan operator is executed or the cached results set is filtered to remove the extra data, Jan 2, 2004 through February 23, 2004.
[0037] In an embodiment, two plan operators may be considered similar if it is expected that a typical user is unlikely to care which results set is returned. For example, in an embodiment, if the content of a cached results set is expected to be nearly the same differing by only a small percentage of rows as that of plan operator's, then the cached result may be used as the results set of plan operator. Whether similar but different, or dissimilar, cached results sets may be used in this way may be controlled by user input. For example, a user may include a command or a parameter in a query that specifies whether similar, but different, cached results sets may be returned, or a variable in user's database session may be set to specify whether similar, but different, cached results sets may be returned, via an Application Programmer Interface ("API").
Parameters or variables may also specify the extent to which two plan operators or signatures may be different, while still allowing the cached results set of one to be used for the results set of the other.
[0038] Also, in an embodiment, if a first plan operator is expected to return all of a results set of a second plan operator in addition to some extra data, and the extra data is expected not to be so voluminous as to obscure the content corresponding to the results set of the second plan operator, then the results set of the first plan operator may be accepted as the results set of the second plan operator as is or after being modified. Similarly, in an embodiment, if a first plan operator is expected to return a smaller results set than a second plan operator, but the missing data is expected not to be important or a small amount, then the results set of the first plan operator may be accepted as the results set of the second plan operator as is or after being modified.

STALE CACHED RESULTS SETS
[0039] Even though plan operators for given queries may be identical, the results set for the plan operators may be different as a result of the queries being executed at different times. In an embodiment, when a cached results set corresponding to a given plan operator is found, a check is performed to see if the cached results set found is stale. For example, in an embodiment, the time a cached results set was computed is stored in association with cached results set in the plan operator output storage. If the age of a the cached results set is greater than a threshold age, the cached results set is no longer preserved in cache or used as a results set for the plan operator of another query. The threshold age may be based on user input as described above.

HARDWARE OVERVIEW
[00401 FIG. 4 is a block diagram that illustrates a computer system 400, is one example of a machine upon which an embodiment of the invention may be implemented.
Specifically computer system 400 may be used as the database server and/or may be programmed to implement the partial query caching method described above. Computer system 400 includes a bus 402 or other communication mechanism for communicating information, and a processor 404 coupled with bus 402 for processing information. Computer system 400 also includes a main memory 406, such as a Random Access Memory (RAM) or other dynamic storage device, coupled to bus 402 for storing information and instructions to be executed by processor 404. Main memory 406 also may be used for storing temporary variables or other intermediate information during execution of instructions to be executed by processor 404. Computer system 400 further includes a Read-Only Memory (ROM) 408 or other static storage device coupled to bus 402 for storing static information and instructions for processor 404. A storage device 410, such as a magnetic disk or optical disk, is provided and coupled to bus 402 for storing information and instructions.
[00411 Computer system 400 may be coupled via bus 402 to a display 412, such as a Cathode Ray Tube (CRT), for displaying information to a computer user. An input device 414, including alphanumeric and other keys, is coupled to bus 402 for communicating information and command selections to processor 404. Another type of user input device is cursor control 416, such as a mouse, a trackball, or cursor direction keys for communicating direction information and command selections to processor 404 and for controlling cursor movement on display 412. This input device typically has two degrees of freedom in two axes, a first axis (e.g., x) and a second axis (e.g., y), that allows the device to specify positions in a plane.
[00421 Computer system 400 may be used for storing results sets of plan operators.
According to one embodiment of the invention, storage of results sets of plan operators and searching for cached results sets of previously executed plan operators in memory 112 is provided by computer system 400 in response to processor 404 executing one or more sequences of one or more instructions contained in main memory 406. Such instructions may be read into main memory 406 from another computer-readable medium, such as storage device 410.
Execution of the sequences of instructions contained in main memory 406 causes processor 404 to perform the process steps described herein. One or more processors in a multi-processing arrangement may also be employed to execute the sequences of instructions contained in main memory 406. In alternative embodiments, hard-wired circuitry may be used in place of or in combination with software instructions to implement the invention. Thus, embodiments of the invention are not limited to any specific combination of hardware circuitry and software.
[0043] The term "computer-readable medium" as used herein is one example of "machine-readable medium", and refers to any medium that participates in providing instructions to processor 404 for execution. Such a medium may take many forms, including but not limited to, non-volatile media, volatile media, and transmission media. Non-volatile media includes, for example, optical or magnetic disks, such as storage device 410. Volatile media includes dynamic memory, such as main memory 406. Transmission media includes coaxial cables, copper wire and fiber optics, including the wires that comprise bus 402. Transmission media can also take the form of acoustic or light waves, such as those generated during radio wave and infrared data communications.
[0044] Common forms of computer-readable media include, for example, a floppy disk, a flexible disk, hard disk, magnetic tape, or any other magnetic medium, a CD-ROM, any other optical medium, punch cards, paper tape, any other physical medium with patterns of holes, a RAM, a PROM, an EPROM, a FLASH-EPROM, any other memory chip or cartridge, a carrier wave as described hereinafter, or any other medium from which a computer can read.
[0045] Various forms of computer readable media may be involved in carrying one or more sequences of one or more instructions to processor 404 for execution. For example, the instructions may initially be carried on a magnetic disk of a remote computer. The remote computer can load the instructions into its dynamic memory and send the instructions over a telephone line using a modem. A modem local to computer system 400 can receive the data on the telephone line and use an infrared transmitter to convert the data to an infrared signal. An infrared detector coupled to bus 402 can receive the data carried in the infrared signal and place the data on bus 402. Bus 402 carries the data to main memory 406, from which processor 404 retrieves and executes the instructions. The instructions received by main memory 406 may optionally be stored on storage device 410 either before or after execution by processor 404.

[0046] Computer system 400 also includes a communication interface 418 coupled to bus 402. Communication interface 418 provides a two-way data communication coupling to a network link 420 that is connected to a local network 422. For example, communication interface 418 may be an Integrated Services Digital Network (ISDN) card or a modem to provide a data communication connection to a corresponding type of telephone line. As another example, communication interface 418 may be a Local Area Network (LAN) card to provide a data communication connection to a compatible LAN. Wireless links may also be implemented. In any such implementation, communication interface 418 sends and receives electrical, electromagnetic or optical signals that carry digital data streams representing various types of information.
[0047] Network link 420 typically provides data communication through one or more networks to other data devices. For example, network link 420 may provide a connection through local network 422 to a host computer 424 or to data equipment operated by an Internet Service Provider (ISP) 426. ISP 426 in turn provides data communication services through the worldwide packet data communication network now commonly referred to as the "Internet"
428. Local network 422 and Internet 428 both use electrical, electromagnetic or optical signals that carry digital data streams. The signals through the various networks and the signals on network link 420 and through communication interface 418, which carry the digital data to and from computer system 400, are exemplary forms of carrier waves transporting the information.
[0048] Computer system 400 can send messages and receive data, including program code, through the network(s), network link 420 and communication interface 418. In the Internet example, a server 420 might transmit a requested code for an application program through Internet 428, ISP 426, local network 422 and communication interface 418. In accordance with the invention, one such downloaded application provides for storage of results sets associated with previously executed plan operators in output storage, as described herein.
[0049] The received code may be executed by processor 404 as it is received, and/or stored in storage device 410, or other non-volatile storage for later execution. In this manner, computer system 400 may obtain application code in the form of a carrier wave.
[0050] In the foregoing specification, embodiments of the invention have been described with reference to numerous specific details that may vary from implementation to implementation.
Thus, the sole and exclusive indicator of what is the invention, and is intended by the applicants to be the invention, is the set of claims that issue from this application, in the specific form in which such claims issue, including any subsequent correction. Any definitions expressly set forth herein for terms contained in such claims shall govern the meaning of such terms as used in the claims.
Hence, no limitation, element, property, feature, advantage or attribute that is not expressly recited in a claim should limit the scope of such claim in any way. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.

Claims (28)

1. A method for computing a query at a database server comprising:

generating a plurality of first execution plans at the database server, wherein each first execution plan of said plurality of first execution plans is for executing a first query, wherein said each first execution plan includes a first plurality of plan operators, each plan operator of said first plurality of plan operators defining operations that are performed by the database server to execute said first query, execution of each plan operator of said first plurality of plan operators generating a first results set;

generating a plurality of first signatures by generating, for each plan operator of the first pluralities of plan operators of said plurality of first execution plans, a first signature;

generating a plurality of first results sets by executing each plan operator in said first pluralities of plan operators to generate a respective first results set for said each plan operator;

storing each first results set of said plurality of first results sets, wherein a first results set of a particular plan operator is stored in association with the respective first signature of said particular plan operator;

after storing the plurality of first results sets in association with said first signatures said database server receiving a second query from a user;

generating a second plan for executing the second query at the database server, wherein the second execution plan includes a second plurality of plan operators that include at least one second plan operator, each plan operator of said second plurality of plan operators defining operations that are performed by the database server to execute said second query;

generating a second signature for said at least one second plan operator of said second plurality of plan operators:

using said second signature, searching signatures of said plurality of first signatures to determine whether at least a subset of a particular first results set of said plurality of first results sets is usable as a second results set of said second operator; and upon determining that at least a subset of said particular first results set of said plurality of first results sets is usable as a second results set of said second operator, computing a second results set for the second query based on the subset of the particular first results set that was stored.
2. The method of claim 1, wherein the first signature of a particular plan operator is generated based on operations performed by said particular plan operator.
3. The method of claim 1, wherein the plan operator of said first pluralities of plan operators that is associated with said particular first results set, at least the subset of which is usable as said second results set, is identical to the second plan operator.
4. The method of claim 1, wherein the plan operator of said first pluralities of plan operators that is associated with said particular first results set, at least the subset of which is usable as said second results set, is not identical to the second plan operator.
5. The method of claim 1, wherein the plan operator of said first pluralities of plan operators that is associated with said particular first results set, at least the subset of which is usable as said second results set, is similar to the second plan operator.
6. The method of claim 1, wherein the plan operator of said first pluralities of plan operators that is associated with said particular first results set, at least the subset of which is usable as said second results set, is identical to the second plan operator, but the first results set and the second results set are different.
7. The method of claim 1, wherein a first execution plan of the plurality of first execution plans includes a third plan operator, the method further comprises:
generating a third results set by executing the third plan operator, wherein the third results set is not stored.
8. The method of claim 1, wherein the step of determining includes at least determining when the first results set was computed.
9. The method of claim 1, wherein a difference exists between the plan operator of said first pluralities of plan operators that is associated with said particular first results set, at least the subset of which is usable as said second results set, and the second plan operator, and the step of computing includes at least modifying the first results set based on the difference.
10. A machine-readable storage medium storing one or more sequences of instructions, which when executed by one or more processors, causes the one or more processors to perform a method comprising the steps of:

generating a plurality of first execution plans at the database server, wherein each first execution plan of said plurality of first execution plans is for executing a first query, wherein said each first execution plan includes a first plurality of plan operators, each plan operator of said first plurality of plan operators defining operations that are performed by the database server to execute said first query, execution of each plan operator of said first plurality of plan operators generating a first results set;

generating a plurality of first signatures by generating, for each plan operator of the first pluralities of plan operators of said plurality of first execution plans, a first signature;

generating a plurality of first results sets by executing each plan operator in said first pluralities of plan operators to generate a respective first results set for said each plan operator;

storing each first results set of said plurality of first results sets, wherein a first results set of a particular plan operator is stored in association with the respective first signature of said particular plan operator;

after storing the plurality of first results sets in association with said first signatures, said database server receiving a second query from a user;

generating a second plan for executing the second query at the database server, wherein the second execution plan includes a second plurality of plan operators that include at least one second plan operator, each plan operator of said second plurality of plan operators defining operations that are performed by the database server to execute said second query;

generating a second signature for said at least one second plan operator of said second plurality of plan operators;

using said second signature, searching signatures of said plurality of first signatures to determine whether at least a subset of a particular first results set of said plurality of first results sets is usable as a second results set of said second operator; and upon determining that at least a subset of said particular first results set of said plurality of first results sets is usable as a second results set of said second operator, computing a second results set for the second query based on the subset of the particular first results set that was stored.
11. The machine-readable storage medium of claim 10, wherein the first signature of a particular plan operator is generated based on operations performed by said particular plan operator.
12. The machine-readable storage medium of claim 10, wherein the plan operator of said first pluralities of plan operators that is associated with said particular first results set, at least the subset of which is usable as said second results set, is identical to the second plan operator.
13. The machine-readable storage medium of claim 10, wherein the plan operator of said first pluralities of plan operators that is associated with said particular first results set, at least the subset of which is usable as said second results set, is not identical to the second plan operator.
14. The machine-readable storage medium of claim 10, wherein the plan operator of said first pluralities of plan operators that is associated with said particular first results set, at least the subset of which is usable as said second results set, is similar to the second plan operator.
15. The machine-readable storage medium of claim 10, wherein the plan operator of said first pluralities of plan operators that is associated with said particular first results set, at least the subset of which is usable as said second results set, is identical to the second plan operator, but the first results set and the second results set are different.
16. The machine-readable storage medium of claim 10, wherein a first execution plan of the plurality of first execution plans includes a third plan operator, and further comprises:

generating a third results set by executing the third plan operator, wherein the third results set is not stored.
17. The machine-readable storage medium of claim 10, wherein the step of determining includes at least determining when the first results set was computed.
18. The machine-readable storage medium of claim 10, wherein a difference exists between the plan operator of said first pluralities of plan operators that is associated with said particular first results set, at least the subset of which is usable as said second results set, and the second plan operator, and the step of computing includes at least modifying the first results set based on the difference.
19. The method of claim 1, wherein receiving a second query from the user includes receiving the second query from a different user.
20. The machine-readable storage medium of claim 10, wherein receiving a second query from the user includes receiving the second query from a different user.
21. The method of claim 1, further comprising computing the subset of the first results set by applying a filter to the first results set that was stored, wherein the subset is generated based on a condition contained in the second query.
22. The machine-readable storage medium of claim 10, further comprising computing the subset of the first results set by applying a filter to the first results set that was stored, wherein the subset is generated based on a condition contained in the second query.
23. The method of claim 1, wherein determining further comprises searching for first signatures that correspond to plan operators that constitute larger portions of the query first.
24. The method of claim 8, further comprising determining whether the age of the first results set is greater than a threshold age;

upon determining that the age of the first results set is greater than the threshold age, (a) removing the first results set from storage or (b) removing the first results set from consideration to use the first results set as part of the second results set.
25. The method of claim 1, wherein plan operators are at least one of: a group plan operator, a join plan operator, a filter plan operator, or a scan table plan operator.
26. The machine-readable storage medium of claim 10, wherein determining further comprises searching for first signatures that correspond to plan operators that constitute larger portions of the query first.
27. The machine-readable storage medium of claim 17, further comprising determining whether the age of the first results set is greater than a threshold age;

upon determining that the age of the first results set is greater than the threshold age, (a) removing the first results set from storage or (b) removing the first results set from consideration to use the first results set as part of the second results set.
28. The machine-readable storage medium of claim 10, wherein plan operators are at least one of: a group plan operator, a join plan operator, a filter plan operator, or a scan table plan operator.
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Families Citing this family (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8521725B1 (en) 2003-12-03 2013-08-27 Google Inc. Systems and methods for improved searching
US7765200B2 (en) * 2005-03-25 2010-07-27 International Business Machines Corporation SQL query problem determination tool
US9128945B1 (en) * 2008-05-16 2015-09-08 Google Inc. Query augmentation
US20100241893A1 (en) * 2009-03-18 2010-09-23 Eric Friedman Interpretation and execution of a customizable database request using an extensible computer process and an available computing environment
US9760658B2 (en) * 2009-10-08 2017-09-12 Oracle International Corporation Memory-mapped objects
US8346792B1 (en) 2010-11-09 2013-01-01 Google Inc. Query generation using structural similarity between documents
US20120173516A1 (en) * 2010-12-31 2012-07-05 Emc Corporation Work file recycling
US8965879B2 (en) 2011-06-03 2015-02-24 Microsoft Technology Licensing, Llc Unique join data caching method
JP5919825B2 (en) 2012-01-05 2016-05-18 富士通株式会社 Data processing method, a distributed processing system and program
US9251209B2 (en) * 2012-03-15 2016-02-02 International Business Machines Corporation Autonomic caching for in memory data grid query processing
CN102880629B (en) * 2012-06-20 2015-06-03 杜小勇 Accelerating query method of probabilistic database
US9317554B2 (en) * 2012-09-26 2016-04-19 Microsoft Technology Licensing, Llc SQL generation for assert, update and delete relational trees
JP6319694B2 (en) * 2015-08-11 2018-05-09 日本電信電話株式会社 Data caching method, the node device and a program
JP6072334B1 (en) * 2016-06-09 2017-02-01 株式会社Cygames The information processing system and method, and program

Family Cites Families (116)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5241305A (en) 1987-05-15 1993-08-31 Newspager Corporation Of America Paper multi-level group messaging with group parsing by message
GB8719572D0 (en) * 1987-08-19 1987-09-23 Krebs M S Sigscan text retrieval system
US5133075A (en) * 1988-12-19 1992-07-21 Hewlett-Packard Company Method of monitoring changes in attribute values of object in an object-oriented database
US5265221A (en) 1989-03-20 1993-11-23 Tandem Computers Access restriction facility method and apparatus
DE69032576T2 (en) * 1990-02-27 1999-04-15 Oracle Corp Dynamic optimization of a single relational access
US5748899A (en) 1990-09-07 1998-05-05 Lowry Computer Products, Inc. Method and system for collecting and processing bar code data
US5276901A (en) 1991-12-16 1994-01-04 International Business Machines Corporation System for controlling group access to objects using group access control folder and group identification as individual user
JP3258063B2 (en) * 1992-02-07 2002-02-18 新日鉄ソリューションズ株式会社 Database search system and method
US5428778A (en) 1992-02-13 1995-06-27 Office Express Pty. Ltd. Selective dissemination of information
CA2079351A1 (en) 1992-02-19 1993-08-20 Bruce A. Tate Scaled depiction of information from a database
US5412804A (en) * 1992-04-30 1995-05-02 Oracle Corporation Extending the semantics of the outer join operator for un-nesting queries to a data base
GB2297180B (en) * 1993-09-27 1998-05-20 Oracle Corp Method and apparatus for parallel processing in a database system
US5581704A (en) * 1993-12-06 1996-12-03 Panasonic Technologies, Inc. System for maintaining data coherency in cache memory by periodically broadcasting invalidation reports from server to client
GB9402935D0 (en) 1994-02-16 1994-04-06 British Telecomm A method for controlling access to a database
CA2138302C (en) 1994-12-15 1999-05-25 Michael S. Fortinsky Provision of secure access to external resources from a distributed computing environment
US5751949A (en) 1995-05-23 1998-05-12 Mci Corporation Data security system and method
JP3738787B2 (en) 1995-10-19 2006-01-25 富士ゼロックス株式会社 Resource management device and resource management method
US5999946A (en) * 1996-04-10 1999-12-07 Harris Corporation Databases in telecommunications
US5903898A (en) * 1996-06-04 1999-05-11 Oracle Corporation Method and apparatus for user selectable logging
US5761654A (en) * 1996-06-05 1998-06-02 Oracle Corporation Memory structure and method for tuning a database statement using a join-tree data structure representation, including selectivity factors, of a master table and detail table
US5802523A (en) * 1996-06-21 1998-09-01 Oracle Corporation Method and apparatus for reducing the memory required to store bind variable descriptors in a database
US5870743A (en) * 1996-06-24 1999-02-09 Oracle Corporation Method and apparatus for parallelizing operations that create a table
JP3747525B2 (en) 1996-08-28 2006-02-22 株式会社日立製作所 Parallel database system retrieval method
US6212578B1 (en) * 1996-09-09 2001-04-03 Oracle Corporation Method and apparatus for managing dependencies in a distributed computing environment for ensuring the safety of remote procedure calls
US5819256A (en) * 1996-11-20 1998-10-06 Oracle Corporation Method and apparatus for processing count statements in a database system
US5884307A (en) * 1997-02-28 1999-03-16 Oracle Corporation Updating bitmapped indexes
US5899988A (en) * 1997-02-28 1999-05-04 Oracle Corporation Bitmapped indexing with high granularity locking
US6141656A (en) * 1997-02-28 2000-10-31 Oracle Corporation Query processing using compressed bitmaps
US5822748A (en) * 1997-02-28 1998-10-13 Oracle Corporation Group by and distinct sort elimination using cost-based optimization
US5963935A (en) * 1997-02-28 1999-10-05 Oracle Corporation Combining bitmaps within a memory limit
US5848408A (en) * 1997-02-28 1998-12-08 Oracle Corporation Method for executing star queries
US5924088A (en) * 1997-02-28 1999-07-13 Oracle Corporation Index selection for an index access path
US6067540A (en) * 1997-02-28 2000-05-23 Oracle Corporation Bitmap segmentation
US5903888A (en) * 1997-02-28 1999-05-11 Oracle Corporation Method and apparatus for using incompatible types of indexes to process a single query
US5907297A (en) * 1997-02-28 1999-05-25 Oracle Corporation Bitmap index compression
US6081800A (en) * 1997-02-28 2000-06-27 Oracle Corporation Creating bitmaps from multi-level identifiers
US6253343B1 (en) * 1997-04-25 2001-06-26 Matsushita Electric Industrial Co., Ltd. Method of design for testability test sequence generation method and semiconductor integrated circuit
US5963932A (en) * 1997-04-29 1999-10-05 Oracle Corporation Method and apparatus for transforming queries
US5842220A (en) * 1997-05-02 1998-11-24 Oracle Corporation Methods and apparatus for exposing members of an object class through class signature interfaces
US5875445A (en) * 1997-05-29 1999-02-23 Oracle Corporation Performance-related estimation using pseudo-ranked trees
US5956704A (en) * 1997-06-05 1999-09-21 Oracle Corporation Method and apparatus for parallelizing operations that insert data into an existing data container
US5937409A (en) * 1997-07-25 1999-08-10 Oracle Corporation Integrating relational databases in an object oriented environment
US6026391A (en) * 1997-10-31 2000-02-15 Oracle Corporation Systems and methods for estimating query response times in a computer system
US6691118B1 (en) * 1997-10-31 2004-02-10 Oracle International Corporation Context management system for modular software architecture
US6275830B1 (en) * 1998-03-18 2001-08-14 Oracle Corporation Compile time variable size paging of constant pools
US6167517A (en) * 1998-04-09 2000-12-26 Oracle Corporation Trusted biometric client authentication
US6341281B1 (en) * 1998-04-14 2002-01-22 Sybase, Inc. Database system with methods for optimizing performance of correlated subqueries by reusing invariant results of operator tree
US6182277B1 (en) * 1998-04-15 2001-01-30 Oracle Corporation Methods and apparatus for declarative programming techniques in an object oriented environment
US6134559A (en) * 1998-04-27 2000-10-17 Oracle Corporation Uniform object model having methods and additional features for integrating objects defined by different foreign object type systems into a single type system
EP0961210A1 (en) * 1998-05-29 1999-12-01 Xerox Corporation Signature file based semantic caching of queries
US6163858A (en) * 1998-06-08 2000-12-19 Oracle Corporation Diagnostic methodology for debugging integrated software
US6138120A (en) * 1998-06-19 2000-10-24 Oracle Corporation System for sharing server sessions across multiple clients
US6510504B2 (en) * 1998-06-29 2003-01-21 Oracle Corporation Methods and apparatus for memory allocation for object instances in an object-oriented software environment
US6219666B1 (en) * 1998-07-13 2001-04-17 Oracle Corporation Autonomous transactions in a database system
US7228300B2 (en) 1998-10-05 2007-06-05 Oracle International Corporation Caching the results of security policy functions
US6578037B1 (en) 1998-10-05 2003-06-10 Oracle Corporation Partitioned access control to a database
US6813617B2 (en) 1998-10-05 2004-11-02 Oracle International Corporation Dynamic generation of optimizer hints
US6487552B1 (en) * 1998-10-05 2002-11-26 Oracle Corporation Database fine-grained access control
US6304974B1 (en) * 1998-11-06 2001-10-16 Oracle Corporation Method and apparatus for managing trusted certificates
US6321238B1 (en) * 1998-12-28 2001-11-20 Oracle Corporation Hybrid shared nothing/shared disk database system
US6477525B1 (en) * 1998-12-28 2002-11-05 Oracle Corporation Rewriting a query in terms of a summary based on one-to-one and one-to-many losslessness of joins
US6496819B1 (en) 1998-12-28 2002-12-17 Oracle Corporation Rewriting a query in terms of a summary based on functional dependencies and join backs, and based on join derivability
US5991754A (en) * 1998-12-28 1999-11-23 Oracle Corporation Rewriting a query in terms of a summary based on aggregate computability and canonical format, and when a dimension table is on the child side of an outer join
US6341340B1 (en) * 1998-12-28 2002-01-22 Oracle Corporation Transitioning ownership of data items between ownership groups
US6351742B1 (en) * 1999-03-18 2002-02-26 Oracle Corporation Method and mechanism for database statement optimization
US6529885B1 (en) * 1999-03-18 2003-03-04 Oracle Corporation Methods and systems for carrying out directory-authenticated electronic transactions including contingency-dependent payments via secure electronic bank drafts
US6401083B1 (en) * 1999-03-18 2002-06-04 Oracle Corporation Method and mechanism for associating properties with objects and instances
US6370522B1 (en) * 1999-03-18 2002-04-09 Oracle Corporation Method and mechanism for extending native optimization in a database system
US6487641B1 (en) * 1999-04-19 2002-11-26 Oracle Corporation Dynamic caches with miss tables
US6314419B1 (en) * 1999-06-04 2001-11-06 Oracle Corporation Methods and apparatus for generating query feedback based on co-occurrence patterns
US6418430B1 (en) * 1999-06-10 2002-07-09 Oracle International Corporation System for efficient content-based retrieval of images
US6466931B1 (en) * 1999-07-30 2002-10-15 International Business Machines Corporation Method and system for transparently caching and reusing query execution plans efficiently
US6601071B1 (en) * 1999-08-04 2003-07-29 Oracle International Corp. Method and system for business to business data interchange using XML
US6549916B1 (en) * 1999-08-05 2003-04-15 Oracle Corporation Event notification system tied to a file system
US6609131B1 (en) * 1999-09-27 2003-08-19 Oracle International Corporation Parallel partition-wise joins
US6665684B2 (en) 1999-09-27 2003-12-16 Oracle International Corporation Partition pruning with composite partitioning
US7093137B1 (en) 1999-09-30 2006-08-15 Casio Computer Co., Ltd. Database management apparatus and encrypting/decrypting system
US6493710B1 (en) * 1999-10-04 2002-12-10 Oracle Corporation Method and apparatus for reducing costs associated with manipulating data
JP4552242B2 (en) * 1999-10-06 2010-09-29 株式会社日立製作所 Query processing system and method using virtual table interface and the interface
US6484179B1 (en) * 1999-10-25 2002-11-19 Oracle Corporation Storing multidimensional data in a relational database management system
US6546382B1 (en) * 1999-11-03 2003-04-08 Oracle Corporation Finding the TOP N values through the execution of a query
US6421666B1 (en) * 1999-11-08 2002-07-16 Oracle Corporation Mechanism for sharing ancillary data between a family of related functions
US6684203B1 (en) * 1999-11-08 2004-01-27 Oracle International Corporation Using global temporary tables to transform queries
US6430550B1 (en) * 1999-12-03 2002-08-06 Oracle Corporation Parallel distinct aggregates
US6546394B1 (en) * 1999-12-28 2003-04-08 Oracle International Corporation Database system having logical row identifiers
US6658405B1 (en) 2000-01-06 2003-12-02 Oracle International Corporation Indexing key ranges
US6671715B1 (en) 2000-01-21 2003-12-30 Microstrategy, Inc. System and method for automatic, real-time delivery of personalized informational and transactional data to users via high throughput content delivery device
US6457020B1 (en) * 2000-03-20 2002-09-24 International Business Machines Corporation Query optimization using a multi-layered object cache
US6332198B1 (en) * 2000-05-20 2001-12-18 Equipe Communications Corporation Network device for supporting multiple redundancy schemes
US20020001307A1 (en) * 2000-05-20 2002-01-03 Equipe Communications Corporation VPI/VCI availability index
US6986060B1 (en) 2000-05-23 2006-01-10 Oracle International Corp. Method and apparatus for sharing a security context between different sessions on a database server
JP4465147B2 (en) * 2000-07-13 2010-05-19 オラクル・インターナショナル・コーポレイション How to calculate the spreadsheet in a database system
US6684207B1 (en) * 2000-08-01 2004-01-27 Oracle International Corp. System and method for online analytical processing
US6622138B1 (en) * 2000-09-06 2003-09-16 Oracle International Corporation Method and apparatus for optimizing computation of OLAP ranking functions
US6581055B1 (en) * 2000-09-11 2003-06-17 Oracle International Corporation Query optimization with switch predicates
US20020095405A1 (en) 2001-01-18 2002-07-18 Hitachi America, Ltd. View definition with mask for cell-level data access control
US7162467B2 (en) * 2001-02-22 2007-01-09 Greenplum, Inc. Systems and methods for managing distributed database resources
US6732085B1 (en) * 2001-05-31 2004-05-04 Oracle International Corporation Method and system for sample size determination for database optimizers
US6691099B1 (en) * 2001-05-31 2004-02-10 Oracle International Corporation Method and system for histogram determination in a database
US6741997B1 (en) * 2001-06-14 2004-05-25 Oracle International Corporation Instantiating objects in distributed database systems
GB2378534B (en) * 2001-08-03 2003-08-20 Oracle Corp SQL execution analysis
JP2003108561A (en) * 2001-09-28 2003-04-11 Kawasaki Steel Systems R & D Corp Database retrieving system
US6615206B1 (en) 2001-09-28 2003-09-02 Oracle International Corporation Techniques for eliminating database table joins based on a join index
GB2398146B (en) 2001-11-01 2005-07-13 Sun Microsystems Inc Directory request caching in distributed computer systems
JP4162184B2 (en) * 2001-11-14 2008-10-08 株式会社日立製作所 Storage device having a means for acquiring execution information of the database management system
US6738762B1 (en) * 2001-11-26 2004-05-18 At&T Corp. Multidimensional substring selectivity estimation using set hashing of cross-counts
CN1421809A (en) 2001-11-27 2003-06-04 英业达股份有限公司 Method of integrating several web page servers according to personal authority limits in network client end
US7152048B1 (en) * 2002-02-07 2006-12-19 Oracle International Corporation Memphis: multiple electronic money payment highlevel integrated security
US7962630B2 (en) 2002-05-10 2011-06-14 Oracle International Corporation Method and mechanism for implementing tagged session pools
US7103608B1 (en) * 2002-05-10 2006-09-05 Oracle International Corporation Method and mechanism for storing and accessing data
US7035846B2 (en) * 2002-09-23 2006-04-25 International Business Machines Corporation Methods, computer programs and apparatus for caching directory queries
US20040064441A1 (en) * 2002-09-27 2004-04-01 Tow Daniel S. Systems and methods for providing structured query language optimization
US7320010B2 (en) * 2002-11-18 2008-01-15 Innopath Software, Inc. Controlling updates of electronic files
US20040139043A1 (en) 2003-01-13 2004-07-15 Oracle International Corporation Attribute relevant access control policies
US7194451B2 (en) * 2004-02-26 2007-03-20 Microsoft Corporation Database monitoring system
US7158966B2 (en) * 2004-03-09 2007-01-02 Microsoft Corporation User intent discovery

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