BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates generally to data warehousing data management and more specifically to optimizing single-row operations within a data warehouse. 
         [0002]    Data warehouses are central repositories of integrated data from a plurality of disparate sources. Data warehouses store current and historical data and are used for creating analytical reports for users throughout an enterprise. Data in data warehouse systems are stored in multiple physical locations called extends. Data warehouse queries typically read and process a large amount of data (known in the art as massive data) and those operations search through an entire set of data (extends) in order to output a final response. The sequence in which extends are read by the data warehouse are inconsequential as all data is read. 
         [0003]    When single-row operations (requiring only one row to be found) are periodically processed, records are read and operated on in small group of extends. Single-row operations are processed for usage and/or customer specific needs and related typically to periodical data verification, housekeeping and/or audit of records created and/or updated in a specific time period. In the case of processing single-row operations, the sequence in which extends are read by the data warehouse becomes a factor to performance of data retrieval. 
       SUMMARY 
       [0004]    As disclosed herein, a method for optimizing single-row operations in a data warehouse, the method comprising: determining one or more single-row operations based on receiving database operations; receiving one or more extends identifiers based on the one or more single-row operations; storing one or more single-row usage statistics in one or more extends lists stores wherein the one or more single-row usage statistics comprises at least one of a hit count and a last hit date; maintaining the one or more single-row usage statistics for the one or more extends identifiers based on the one or more single-row operations; sorting a logical sequence of the one or more extends identifiers in one or more extends lists stores based on the one or more single-row usage statistics and maintaining the logical sequence based on determining a further one or more single-row operations. A computer system and a computer program product corresponding to the above method are also disclosed herein. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]      FIG. 1  is a functional block diagram illustrating a computing environment, in accordance with an embodiment of the present invention; 
           [0006]      FIG. 2A  depicts an extends list store with sample single-row usage tracking statistics, in accordance with an embodiment of the present invention; 
           [0007]      FIG. 2B  is a flowchart depicting single-row usage tracking, in accordance with an embodiment of the present invention; 
           [0008]      FIG. 3  is a flowchart depicting single-row operations monitoring, in accordance with an embodiment of the present invention; and 
           [0009]      FIG. 4  depicts a block diagram of components of the server and/or the computing device, in accordance with an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0010]    Embodiments of the present invention provide systems, methods and computer program products for changing the logical order of extends in a data warehouse to optimize searching records when executing single-row (S-R) operations. 
         [0011]    A feature of a data warehouse is that each extends instance comprises metadata containing various statistical information about the content stored. The metadata information comprises data such as, but not limited to, minimal and maximal values for each column stored in an extends. Before reading physical data from a database, a data warehouse database engine first checks low level statistics to filter records that are not required for processing in a query. 
         [0012]    Embodiments of the present invention monitor execution of data warehouse operations, determines when single-row operations are executed and logs ‘hits’ or access frequency that occur in each extends. Based on extends hits, a sort sequence of extends is determined and maintained to prioritize the order in which extends are processed by a data warehouse during single-row operations. Single-row operations are optimized as the logical sequencing of extends increases the probability of finding records of interest earlier in a search and continued read operations of all extends can be abandoned. 
         [0013]    Embodiments of the present invention will now be described in detail with reference to the figures. It should be noted that references in the specification to “an exemplary embodiment,” “other embodiments,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. 
         [0014]      FIG. 1  is a functional block diagram of computing environment  100 , in accordance with an embodiment of the present invention. Computing environment  100  comprises communication device  110  and computer system  130 , interconnected via network  150 . Communication device  110  and computer system  130  can be desktop computers, laptop computers, specialized computer servers, or the like. In certain embodiments, communication device  110  and computer system  130  represent computer systems utilizing clustered computers and components acting as a single pool of seamless resources via network  150 . For example, such embodiments can be used in data center, cloud computing, storage area network (SAN) and network attached storage (NAS) applications. In general, communication device  110  and computer system  130  are representative of any electronic devices, or combination of electronic devices, capable of executing computer readable program instructions, as described in detail with regard to  FIG. 4 . 
         [0015]    Network  150  can be, for example, a local area network (LAN), a wide area network (WAN) such as, the Internet, or a combination of the two and include wired, wireless, or fiber optic connections. In general, network  150  can be any combination of connections and protocols that will support communications between communication device  110  and computer system  130 , in accordance with an embodiment of the present invention. 
         [0016]    In one embodiment of the present invention, communication device  110  comprises data warehouse  112  and query tool  122 . Data warehouse  112  can be a plurality of data warehouses  112  within communication device  110 . Query tool  122  can be a plurality of query tools  122  used to retrieve and manage data within data warehouse  112  and comprises any combination of commercial or custom software products (not shown) associated with Data warehouse  112  data management. Data warehouse  112  can be described as a warehouse of current and historical data used for creating analytical reports for users throughout an enterprise. Data warehouse  112  can be operated by a plurality of database management systems (DBMS) and comprise any combination of commercial or custom software products (not shown) associated with operating and maintaining data warehouse  112 . 
         [0017]    In one embodiment of the present invention, data warehouse  112  further comprises extends D 1   114 , extends D 2   116 , extends D 3   118  and extends list store  120 . Extends D 1   114 , extends D 2   116  and extends D 3   118  can be a plurality of extends D 1   114 , extends D 2   116  and extends D 3   118  within data warehouse  112 . Data and associated metadata in data warehouse  112  are stored in multiple physical locations. Extends D 1   114 , extends D 2   116  and extends D 3   118  represent physical locations comprising metadata and data used in the operation of a data warehouse  112  which can be distributed and/or integrated in a plurality of communication device  110 . While data warehouse  112  depicts three extends (e.g., extends D 1   114 , extends D 2   116  and extends D 3   118 ), the number of extends used by data warehouse  112  are based on predetermined data warehouse  112  implementation needs. Further, each extends metadata comprises statistical information such as, but not limited to, minimal and maximal values for each column in an extends. 
         [0018]    In one embodiment of the present invention, extends list store  120  can be a plurality of extends list stores  120  within data warehouse  112 . Extends list store  120  is a list of extends (e.g., extends D 1   114 , extends D 2   116  and extends D 3   118 ) that data warehouse  112  uses as source reference to search metdata and data in each identified extends in extends list store  120 . Extends list store  120  is modified by embodiments of the present invention to maintain access frequency (i.e., hit count) and extends identifier (ID) logical sequence. 
         [0019]    In one embodiment of the present invention, computer system  130  comprises extends optimizer  132 . Extends optimizer  132  further comprises S-R monitor  134  and S-R manager  136 . Extends optimizer  132  comprises any combination of commercial or custom software products (not shown) associated with operating and maintaining extends optimizer  132 . It should be noted that, extends optimizer  132  can be implemented as an integrated or distributed application. 
         [0020]    In one embodiment of the present invention, S-R monitor  134  can be a plurality of S-R monitors  134  within extends optimizer  132 . S-R monitor  134  monitors data warehouse  112  operation for single-row database operations (e.g., query, update, delete). Single-row operations can be determined by examining query statement logic for single-row operations sent by query tool  122  toward data warehouse  112 . Single-row operations can be determined by examining received data warehouse  112  operation statements such as, but not limited to, (1) unique value field, using ‘where’ clause (e.g., where id=4); (2) explicitly, using ‘select top 1’ clause; and (3) logically using ‘exists’ clause. In case (1) unique value field, the definition of unique key is data that can contain one of a specific value. Known by one skilled in the art, key fields are defined in database schema and provide attributes to indicate which key fields contain unique values. In case (2) explicitly, the ‘top 1’ parameter is an option in a ‘select’ clause resulting in a single-row result. In case (3) logically, where exists clause is satisfied when the first occurrence of a value is found (e.g., logical True/False). In the prior examples, a single-row operation is identified and when data warehouse  112  finds a record of interest for the single-row operation in an extends, S-R monitor  134  receives the extends ID (e.g., extends D 1   114 , extends D 2   116  and extends D 3   118 ) from data warehouse  112 . It should be noted that Structured Query Language (SQL) is an example of a plurality of query languages that can be used with data warehouse  112  operations. When a single-row operation is processed, S-R monitor  134  sends the extends ID (e.g., extends D 1   114 , extends D 2   116  and extends D 3   118 ) toward S-R manager  136 . 
         [0021]    In one embodiment of the present invention, S-R manager  136  can be a plurality of S-R managers  136  within extends optimizer  132 . S-R manager  136  determines extends hits and logical sort order of extends ID in extends list store  120  based on single-row hit statistics (usage) in extends list store  120 . S-R manager  136  stores the extends hits and logical sort order of extends ID in extends list store  120 . It should be noted that sorting of extends can be performed by a range of predetermined methods such as, but not limited to, real-time (i.e., during each extends hit occurrence), periodically by a predetermined schedule and based on a predetermined hit count threshold. In one embodiment of the present invention, after an extend hit occurs, a compare of the hit value of the current extends ID with a logically adjacent extends ID can determine if a sequence change in extends search order is needed. A single exchange method based on exchanging extends sequence position with adjacent extends produces a gradual sort, similar to a single pass bubble sort, to reduce rapid and drastic change of extends list store  120  sequence content. In another embodiment of the present invention, predetermined periodic comparison sorts can be executed. Sort methods such as, but not limited to, bubble sort, comb sort, heapsort, merge sort and quicksort are known by one skilled in the art as comparison sorts. These sort methods can logically sequence extends list store  120  based on access frequency (i.e., hit count) and can be combined with other attributes such as, but not limited to, a range of last hit dates to group extends ID&#39;s and reduce the collection of each logical sort. 
         [0022]      FIG. 2A  depicts an extends list store with sample single-row usage tracking statistics, in accordance with an embodiment of the present invention. The extends list store sample  200  represents one aspect of data that can be contained in extends list store  120 . 
         [0023]    Heading  202  Extends_ID is an identifier of Extends. The values of extends range from D 1  to Dn, where Dn is any number of extends datasets in the sample table (i.e., store). It should be noted that extends identifier format is based on data warehouse  112  implementation needs. 
         [0024]    Heading  204  Hit_Count is a hit count of Extends ID. Heading  204  Hit_Count can be an added data column in extends list store  120  as part of data warehouse  112 . The value in each row of heading  204  Hit_Count column is based on the number of times heading  202  Extends_ID is found to contain data for a single-row operation and is calculated by S-R manager  136 . 
         [0025]    Heading  206  SR_Sequence is a single-row logical order (i.e., priority sequence) determined by S-R manager  136 . Heading  206  SR_Sequence can be an added and/or existing data column in extends list store  120  as part of data warehouse  112 . As heading  204  Hit_Count values increase, the logical order can change when compared to other heading  204  Hit_Count values associated to heading  202  Extends_ID values. The single-row logical order are used by data warehouse  112  in single-row searches to sequence searching of extends. 
         [0026]    Heading  208  Last_Hit is a last extends hit date stamp. Heading  208  Last_Hit can be an added data column in extends list store  120  as part of data warehouse  112 . When a value of heading  204  Hit_Count increases for an extends ID (e.g., heading  202  Extends_ID) a current date stamp is recorded. Heading  208  Last_Hit value depicted as day month year and is a representation of one embodiment of the present invention. Heading  208  Last_Hit can be used in conjunction with heading  204  Hit_Count values to determine a new sequence of extends that have been accessed recently. For example, a predetermined value of 24 hours is established to contribute to the sequence process of S-R manager  136 . In this example, heading  206  SR_Sequence value considers heading  208  Last_Hit dates of 25.9.2015 to group extends associated to the sorting operation. Older values heading  208  Last_Hit dates of value 25.9.2015 contain heading  206  SR_Sequence value greater than heading  206  SR_Sequence values within the 25.9.2015 grouping. 
         [0027]    Heading  210  P_Hit_Count and heading  212  P_SR_Sequence are previous values of respective heading  204  Hit_Count and heading  206  SR_Sequence hit count of Extends. Heading  210  P_Hit_Count and heading  212  P_SR_Sequence are provided for illustrative purposes and are not required in embodiments of the present invention. For example, heading  202  Extends_ID values D 2  and D 3  are heading  210  P_Hit_Count values of 5 and 5 respectively. Heading  212  P_SR_Sequence value is 3 for heading  202  Extends_ID value D 3  priority increased to heading  206  SR_Sequence value of 2 when heading  204  Hit_Count increased to value 6 for 25.9.2015 group of heading  208  Last_Hit. Note that heading  202  Extends_ID value D 5  is heading  204  Hit_Count value 10 but is not heading  206  SR_Sequence value of 1 since heading  202  Extends_ID value D 5  is older and not part of heading  208  Last_Hit value 25.9.2015 grouping. 
         [0028]      FIG. 2B  is a flowchart depicting single-row usage tracking, in accordance with an embodiment of the present invention. The single-row usage tracking flow sample  220  represents one embodiment of the present invention. 
         [0029]    Step  222  Receive Extends ID is the extends ID of the extends found to contain records of interest in a single-row operation. 
         [0030]    In step  224  Search extends ID, searches for the extends ID from step  222  Receive Extends ID in extends list store  120 . Results of step  224  Search extends ID comprise data such as, but not limited to, extends ID, hit count, single-row sequence and last hit date stamp (e.g., heading  202  Extends_ID, heading  204  Hit_Count, heading  206  SR_Sequence and heading  208  Last_Hit). 
         [0031]    Step  226  Increment Hit Count, increments current hit count from step  224  Search extends ID for the extends ID being updated. 
         [0032]    In step  228  Sort Sequence, the hit count from step  226  Increment Hit Count is compared to other hit counts in extends list store  120  for the extends ID&#39;s current system date. If the hit counts is a high access frequency as compared to logically adjacent extends ID&#39;s having a low access frequency, the extends ID sequence position can be exchanged. It should be noted that, some embodiments of the present invention can perform comparison sorts such as, but not limited to, bubble sort, comb sort, heapsort, merge sort and quicksort periodically based on a predetermined threshold of usage statistics updates and/or a predetermined schedule. When step  228  Sort Sequence completes processing, respective extends ID&#39;s are logically moved higher in extends list store  120 . 
         [0033]      FIG. 3  is a flowchart depicting single-row operations monitoring, in accordance with an embodiment of the present invention. Step  302  Receive DW query in S-R monitor flow diagram  300 , receives a query sent toward data warehouse  112  for processing. Embodiments of the present invention can retrieve and/or receive query contents and/or portions of query syntax to determine single-row operations by data warehouse  112 . 
         [0034]    Step  304  Determine S-R operation, analyzes and determines if a single-row operation is requested for processing by data warehouse  112 . A single-row query can be determined by previously described techniques such as, but not limited to, (1) unique value field; (2) explicitly (using select top 1); and (3) logically (where exists clause). It should be noted that determination techniques identified are in SQL language as an example and a plurality of query languages can have similar identifiers to determine if a query is a single-row operation. As an example, a given query for field ‘id’ that is equal to 44 (id=44) is processed in data warehouse  112 . Data warehouse  112  searches for a single record (single-row) where id is equal to 44 (id=44) by selecting the first extends ID in extends list store  120  and searches the identified extends (e.g., extends D 1   114 ) metadata. If the extends metadata for extends D 1   114  comprise key field “id”, minimal value of 0 and maximal value of 25 then data warehouse  112  query processing advances to select the next extends ID (e.g., extends D 3   118 ) from extends list store  120  and queries extends D 3   118  metadata. Continuing with the example, extends D 3   118  metadata comprises key field “id”, minimal value of 30 and a maximal value of 100. Since id equal to 44 (id=44) is within the metadata range data for extends D 3   118 , it is statistically probable that the data row (record of interest) exists in extends D 3   118 . When data warehouse  112  query processing finds id equal to 44 (id=44) does exist in extends D 3   118  then step  306  DW S-R data found evaluates as true otherwise data warehouse  112  query process continues until all extends in extends list store  120  are searched. If data warehouse  112  query processing finds no records to satisfy the query then S-R monitor flow diagram  300  ends. It should be noted that some embodiments of the present invention can provide S-R monitor  134  with the ability to have data warehouse  112  query processing to abandon searching metadata after a single-row operation is satisfied with a record of interest. In other embodiments of the present invention, data warehouse  112  query processing automatically terminates when single-row results are located. 
         [0035]    When step  306  DW S-R data found is true, step  308  Receive DW extends ID receives the extends ID where data warehouse  112  found the record of interest (e.g., extends D 3   118 ). 
         [0036]    Step  310  Send extends ID toward S-R Manager, sends the extends ID (e.g., extends D 3   118 ) from step  308  Receive DW extends ID toward S-R manager  136  to update extends usage (i.e., a hit). 
         [0037]      FIG. 4  depicts a block diagram of components of communication device  110  and computer system  130  in accordance with an illustrative embodiment of the present invention. It should be appreciated that  FIG. 4  provides only an illustration of one implementation and does not imply any limitations with regard to the environments in which different embodiments may be implemented. Many modifications to the depicted environment may be made. 
         [0038]    Computer system  400  includes communications fabric  402 , which provides communications between computer processor(s)  404 , memory  406 , persistent storage  408 , communications unit  410  and input/output (I/O) interface(s)  412 . Communications fabric  402  can be implemented with any architecture designed for passing data and/or control information between processors (such as, microprocessors, communications and network processors, etc.), system memory, peripheral devices, and any other hardware components within a system. For example, communications fabric  402  can be implemented with one or more buses. 
         [0039]    Computer system  400  includes processors  404 , cache  416 , memory  406 , persistent storage  408 , communications unit  410 , input/output (I/O) interface(s)  412  and communications fabric  402 . Communications fabric  402  provides communications between cache  416 , memory  406 , persistent storage  408 , communications unit  410 , and input/output (I/O) interface(s)  412 . Communications fabric  402  can be implemented with any architecture designed for passing data and/or control information between processors (such as, microprocessors, communications and network processors, etc.), system memory, peripheral devices, and any other hardware components within a system. For example, communications fabric  402  can be implemented with one or more buses or a crossbar switch. 
         [0040]    Memory  406  and persistent storage  408  are computer readable storage media. In this embodiment, memory  406  includes random access memory (RAM). In general, memory  406  can include any suitable volatile or non-volatile computer readable storage media. Cache  416  is a fast memory that enhances the performance of processors  404  by holding recently accessed data, and data near recently accessed data, from memory  406 . 
         [0041]    Program instructions and data used to practice embodiments of the present invention may be stored in persistent storage  408  and in memory  406  for execution by one or more of the respective processors  404  via cache  416 . In an embodiment, persistent storage  408  includes a magnetic hard disk drive. Alternatively, or in addition to a magnetic hard disk drive, persistent storage  408  can include a solid state hard drive, a semiconductor storage device, read-only memory (ROM), erasable programmable read-only memory (EPROM), flash memory, or any other computer readable storage media that is capable of storing program instructions or digital information. 
         [0042]    The media used by persistent storage  408  may also be removable. For example, a removable hard drive may be used for persistent storage  408 . Other examples include optical and magnetic disks, thumb drives, and smart cards that are inserted into a drive for transfer onto another computer readable storage medium that is also part of persistent storage  408 . 
         [0043]    Communications unit  410 , in these examples, provides for communications with other data processing systems or devices. In these examples, communications unit  410  includes one or more network interface cards. Communications unit  410  may provide communications through the use of either or both physical and wireless communications links. Program instructions and data used to practice embodiments of the present invention may be downloaded to persistent storage  408  through communications unit  410 . 
         [0044]    I/O interface(s)  412  allows for input and output of data with other devices that may be connected to each computer system. For example, I/O interface  412  may provide a connection to external devices  418  such as, a keyboard, keypad, a touch screen, and/or some other suitable input device. External devices  418  can also include portable computer readable storage media such as, for example, thumb drives, portable optical or magnetic disks, and memory cards. Software and data used to practice embodiments of the present invention can be stored on such portable computer readable storage media and can be loaded onto persistent storage  408  via I/O interface(s)  412 . I/O interface(s)  412  also connect to display  420 . 
         [0045]    Display  420  provides a mechanism to display data to a user and may be, for example, a computer monitor. 
         [0046]    The programs described herein are identified based upon the application for which they are implemented in a specific embodiment of the invention. However, it should be appreciated that any particular program nomenclature herein is used merely for convenience, and thus the invention should not be limited to use solely in any specific application identified and/or implied by such nomenclature. 
         [0047]    The present invention may be a system, a method, and/or a computer program product. The computer program product may include a computer readable storage medium (or media) having computer readable program instructions thereon for causing a processor to carry out aspects of the present invention. 
         [0048]    The computer readable storage medium can be a tangible device that can retain and store instructions for use by an instruction execution device. The computer readable storage medium may be, for example, but is not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of the computer readable storage medium includes the following: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanically encoded device such as, punch-cards or raised structures in a groove having instructions recorded thereon, and any suitable combination of the foregoing. A computer readable storage medium, as used herein, is not to be construed as being transitory signals per se, such as, radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission media (e.g., light pulses passing through a fiber-optic cable), or electrical signals transmitted through a wire. 
         [0049]    Computer readable program instructions described herein can be downloaded to respective computing/processing devices from a computer readable storage medium or to an external computer or external storage device via a network, for example, the Internet, a local area network, a wide area network and/or a wireless network. The network may comprise copper transmission cables, optical transmission fibers, wireless transmission, routers, firewalls, switches, gateway computers and/or edge servers. A network adapter card or network interface in each computing/processing device receives computer readable program instructions from the network and forwards the computer readable program instructions for storage in a computer readable storage medium within the respective computing/processing device. 
         [0050]    Computer readable program instructions for carrying out operations of the present invention may be assembler instructions, instruction-set-architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state-setting data, or either source code or object code written in any combination of one or more programming languages, including an object oriented programming language such as, Smalltalk, C++ or the like, and conventional procedural programming languages, such as, the “C” programming language or similar programming languages. The computer readable program instructions may execute entirely on the user&#39;s computer, partly on the user&#39;s computer, as a stand-alone software package, partly on the user&#39;s computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user&#39;s computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider). In some embodiments, electronic circuitry including, for example, programmable logic circuitry, field-programmable gate arrays (FPGA), or programmable logic arrays (PLA) may execute the computer readable program instructions by utilizing state information of the computer readable program instructions to personalize the electronic circuitry, in order to perform aspects of the present invention. 
         [0051]    Aspects of the present invention are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer readable program instructions. 
         [0052]    These computer readable program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. These computer readable program instructions may also be stored in a computer readable storage medium that can direct a computer, a programmable data processing apparatus, and/or other devices to function in a particular manner, such that the computer readable storage medium having instructions stored therein comprises an article of manufacture including instructions which implement aspects of the function/act specified in the flowchart and/or block diagram block or blocks. 
         [0053]    The computer readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus or other device to produce a computer implemented process, such that the instructions which execute on the computer, other programmable apparatus, or other device implement the functions/acts specified in the flowchart and/or block diagram block or blocks. 
         [0054]    The flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts or carry out combinations of special purpose hardware and computer instructions. 
         [0055]    The descriptions of the various embodiments of the present invention have been presented for purposes of illustration, but are not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. The terminology used herein was chosen to best explain the principles of the embodiment, the practical application or technical improvement over technologies found in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.
An approach for optimizing single-row operations in a data warehouse. Single-row operations are determined based on receiving database operations. Extends identifiers are received based on the single-row operations. Single-row usage statistics are stored in extends lists stores where single-row usage statistics include at least one of a hit count and a last hit date. Single-row usage statistics are maintained for extends identifiers based on single-row operations. A logical sequence of the extends identifiers in extends lists stores are sorted based on single-row usage statistics and the logical sequence is maintained based on determining a further single-row operations.