JP2012141830A - Index generation device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an index generation device and a method for generating information for partially decompressing a compressed file in order to read a necessary record from the compressed file.SOLUTION: An index generation device 10 successively transfers a plurality of records composing an uncompressed file 51 to a file compression device 60, and applies and successively stores the indexes of the records to be transferred in an index file 31. Then, the index generation device 10 monitors a compression processing state in the file compression device 60, and acquires the block size of one compressed block from the file compression device 60 in response to the detection of the end of the compression processing of one block, and calculates the block position of one compressed block from the beginning of a compressed file 61 on the basis of the acquired block size of one compressed block, and further stores the block position in the index file 31.

Description

  The present invention relates to an index generation apparatus and method.

  Conventionally, when a file system stores a file, the file system may be compressed and stored in order to reduce the amount of data to be stored. The saved post-compression file is decompressed and restored to the original file. Here, since the compression process processes the entire file at once, it is usually not possible to decompress only part of the compressed file.

  In such compression and decompression processing, when a part of the file is changed, the compressed file of the original file before the change and the compressed file obtained by compressing only the changed part are saved, and the original file before the change is stored at the time of decompression. Patent Document 1 that discloses a technique for combining with a file is known.

  In the technique disclosed in Patent Document 1, the control unit holds a compressed file obtained by compressing an original file in a compressed file storage area, and when the original file is changed, a pointer indicating the changed part is stored in the pointer storage area. Hold the changed compressed file obtained by partially compressing the changed portion of the original file, and hold it in the changed compressed file storage area. Then, the control unit decompresses the compressed file in the compressed file storage area through the compression / decompression processing unit when the file before the change is necessary, and restores the file before the change, and compresses the file after the change is necessary. / The modified compressed file in the modified compressed file storage area is decompressed through the decompression processing unit, the file is incorporated into the file before modification according to the pointer in the pointer storage area, and the modified file is restored.

JP 07-141234 A

  However, the technique disclosed in Patent Literature 1 retains a compressed file of a file before the change and a compressed file of only the changed portion in preparation for returning the changed file to the file before the change. It ’s just that. That is, even with the technique disclosed in Patent Document 1, in order to acquire necessary data from the compressed file, it is necessary to decompress all the compressed files.

  Therefore, there is a need for an apparatus and a method for generating information for partially decompressing a compressed file in order to read a necessary record from the compressed file.

  An object of the present invention is to provide an index generation apparatus and method for generating information for partially decompressing a compressed file in order to read a necessary record from the compressed file.

  The present invention provides the following solutions.

  (1) An index generation device that can communicate with a file compression device that compresses and decompresses a file block by block, and sequentially delivers a plurality of records constituting a file to be compressed to the file compression device; A record information acquisition unit that assigns an index of a record to be delivered and sequentially stores the index in the index storage unit; a compression processing state monitoring unit that monitors a compression processing state in the file compression device and detects the end of one block compression processing; In response to the fact that the compression processing state monitoring unit detects the end of the compression processing of the one block, information related to the one block after compression is acquired from the file compression apparatus, and the acquired one block after compression is acquired. Based on such information, information for specifying the one block after compression is generated and Index generation apparatus and a block information obtaining means further stores the index storage unit.

  According to the configuration of (1), the index generation device according to the present invention sequentially delivers a plurality of records constituting a file to be compressed to the file compression device, assigns an index of the records to be delivered, and sequentially stores them in the index storage means. . Next, the index generation device monitors the compression processing state in the file compression device, and acquires information on one block after compression from the file compression device in response to detecting the end of the compression processing of one block. Based on the acquired information relating to one block after compression, information for specifying one block after compression is generated and further stored in the index storage means.

  That is, the index generation device according to the present invention delivers a file to be compressed to a file compression device for each record, sequentially stores the index of the delivered record in an index storage unit, and relates to one block after compression from the file compression device. Information is acquired, information for specifying one block after compression is generated, and further stored in the index storage means. Therefore, the index generation device according to the present invention sequentially stores the index of the record delivered for compression in order to read out the necessary record from the compressed file, and further includes information for specifying one block after compression. Since it is stored, information for partially decompressing the compressed file can be generated.

  (2) Based on the record size of the record to be transferred, the record information acquisition unit is a block of the file before compression that is a block of the file before compression that includes the record to be transferred and that includes the record to be transferred. The index generation device according to (1), wherein an offset of the record to be transferred from the head is calculated and further stored in the index storage unit in association with the record to be transferred together with a record size.

  According to the configuration of (2), the index generation device according to (2) is the pre-compression file corresponding to the post-compression block including the record to be transferred and including the record to be transferred in (1). The offset of the record to be transferred from the head of the block is calculated, and further stored in the index storage means in association with the record to be transferred together with the record size. Therefore, the index generation device according to (2) sequentially stores the index of the record to be delivered for compression in order to read out the necessary record from the compressed file, and stores the block of the file before compression corresponding to the block after compression. Since both the offset from the head and the record size are stored, it is possible to generate information for decompressing up to the delivered record in one corresponding block of the compressed file.

  (3) A method executed by an index generation device that can communicate with a file compression device that compresses and decompresses a file block by block, and sequentially delivers a plurality of records constituting a file to be compressed to the file compression device. A record information acquisition step for assigning an index of the record to be delivered and sequentially storing the index in the index storage means, and a compression processing state monitor for monitoring a compression processing state in the file compression device and detecting the end of the compression processing of one block And when the compression processing state monitoring step detects the end of the compression processing of the one block, the information related to the one block after compression is acquired from the file compression device, and the acquired post-compression Based on the information related to the one block, the one block after compression is How and a block information obtaining step of further stored in the index storage means to generate information for constant.

  Therefore, the method according to the present invention sequentially stores the index of the record delivered for compression in order to read out the necessary record from the compressed file, and specifies one block after compression, as in (1). This information is further stored, so that information for partially decompressing the compressed file can be generated.

  According to the present invention, it is possible to provide an index generation device that operates in cooperation with a file compression device that compresses and decompresses a file block by block, and generates and stores information that can identify a block in a post-compression file. it can. As a result, the user can specify a block to be decompressed when reading a predetermined record from the compressed file.

It is a functional block diagram which shows the function structure of the index production | generation apparatus which concerns on one Embodiment of this invention. It is explanatory drawing for demonstrating the function of the index production | generation apparatus which concerns on one Embodiment of this invention. It is a figure which shows an example of the index file which concerns on Embodiment 1 of this invention. It is a flowchart which shows the index production | generation process of the index production | generation apparatus which concerns on Embodiment 1 of this invention. It is a flowchart which shows the search process which searches using the index file produced | generated by the index production | generation apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows an example of the index file which concerns on Embodiment 2 of this invention. It is a flowchart which shows the index production | generation process of the index production | generation apparatus which concerns on Embodiment 2 of this invention. It is a flowchart which shows the search process which searches using the index file produced | generated by the index production | generation apparatus which concerns on Embodiment 2 of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  The index generation device 10 of this embodiment is applied to a computer and its peripheral devices. Each unit in the present embodiment is configured by hardware included in a computer and its peripheral devices, and software that controls the hardware.

  The hardware includes a storage unit, a communication device, a display device, and an input device in addition to a CPU (Central Processing Unit) as a control unit. Examples of the storage unit include a memory (RAM: Random Access Memory, ROM: Read Only Memory, etc.), a hard disk drive (HDD: Hard Disk Drive), and an optical disk (CD: Compact Disc, DVD: Digital Versatile Drive, etc.). It is done. Examples of the communication device include various wired and wireless interface devices for communicating with the file compression device 60. Examples of the display device include various displays such as a liquid crystal display and a plasma display. Examples of the input device include a keyboard and a pointing device (mouse, tracking ball, etc.).

  The software includes a computer program and data for controlling the hardware. The computer program and data are stored in the storage unit, and are appropriately executed and referenced by the control unit. The computer program and data can be distributed via a communication line, or can be recorded on a computer-readable medium such as a CD-ROM and distributed.

[Embodiment 1]
FIG. 1 is a functional block diagram showing a functional configuration of an index generation device 10 according to an embodiment of the present invention. In FIG. 1, the configuration of the file compression device 60 is shown for explaining the index generation device 10. FIG. 2 is an explanatory diagram for explaining the function of the index generation device 10 according to an embodiment of the present invention. FIG. 3 is a diagram showing an example of the index file 31 according to the first embodiment of the present invention. 3A shows an example of the index file 31, and FIG. 3B shows an example of the pre-compression file 51, the post-compression file 61, and the decompression block 52 partially decompressed from the post-compression file 61. Show.

  The index generation device 10 is communicably connected to a file compression device 60 that compresses and decompresses a file for each block. The index generation device 10 includes an index file 31 as an index storage unit, a record transfer unit 11 as a record transfer unit, a record information acquisition unit 12 as a record information acquisition unit, and a compression process as a compression processing state monitoring unit A state monitoring unit 13 and a block information acquisition unit 14 as a block information acquisition unit are provided. 1 will be described in detail with reference to FIGS. 2 and 3. FIG.

  The record delivery unit 11 sequentially delivers a plurality of records constituting the file to be compressed (pre-compression file 51) to the file compression apparatus 60. Specifically, the record delivery unit 11 acquires records constituting the pre-compression file 51 one record at a time, and sequentially delivers the records to the file compression apparatus 60. For example, when the record length is variable, the record delivery unit 11 acquires the record from the start code to the end code as one record. When the record length is fixed, the record delivery unit 11 acquires one fixed-length record, Delivered according to the interface with the file compression device 60.

In the file compression device 60, the target record receiving unit 71 sequentially stores the delivered one record in the compression buffer 62. The file information update unit 72 updates the file information table 63. The file information table 63 includes, for example, a block number that is created every time compression is completed, a buffer size that is the remaining size of the compression buffer 62 that stores the delivered record, and a compressed block size. A certain post-compression block size is stored in memory. The buffer size monitoring unit 73 monitors the buffer size of the compression buffer 62. When the compression buffer 62 reaches a predetermined condition, the block compression unit 74 compresses the data in the compression buffer 62 and sequentially generates the compressed blocks. Further, the post-compression block size recording unit 75 records the post-compression block size in the file information table 63.
That is, as shown in FIG. 2, when the record constituting the pre-compression file 51 is delivered and the compression buffer 62 satisfies a predetermined condition, one block (for example, block 61i) of the post-compression file 61 is generated. .

Here, the predetermined condition is when the buffer size of the compression buffer 62 becomes 0 or negative. For example, when one delivered record is stored and the buffer size of the compression buffer 62 becomes 0, the file compression apparatus 60 generates one block of compressed data. Alternatively, when one delivered record is stored and the buffer size of the compression buffer 62 becomes negative, the file compression device 60 generates one block of compressed data and clears the last received record The data is stored in the compression buffer 62.
Furthermore, the file compression apparatus 60 associates a block number with one block after compression every time compression is completed. The size of one block after compression is the length from the first data to the last data constituting the block expressed by the number of bytes (8 bits), and is different for each block.

  The record information acquisition unit 12 assigns an index of the record delivered by the record delivery unit 11 and sequentially stores it in the index file 31. The index of the record may be created in advance, or may be acquired from the format information of the pre-compression file 51. Specifically, the record information acquisition unit 12 acquires an index of a record indicated by “key1” or the like in FIG. 3A from index information created in advance in association with the record. Alternatively, the record information acquisition unit 12 reads and acquires an index (for example, time information in the log file) from the read record according to the relative position and length of the index in the record. Then, the record information acquisition unit 12 sequentially stores the acquired index in the index file 31 as shown in FIG.

  The compression processing state monitoring unit 13 monitors the compression processing state in the file compression device 60 and detects the end of compression processing for one block. Specifically, the compression processing state monitoring unit 13 monitors the file information table 63 indicating the compression processing state in the file compression device 60 in accordance with the interface with the file compression device 60. That is, the compression processing state monitoring unit 13 detects the end of the compression processing when the block number of the file information table 63 indicating the compression processing state is increased (+1), for example.

  The compression process state monitoring unit 13 may detect the end of the compression process from the buffer size. For example, when the file compression device 60 stores the delivered one record, the buffer size of the compression buffer 62 decreases, and when the file compression device 60 clears the compression buffer 62 after compression, the buffer size increases.

  The block information acquisition unit 14 acquires the information related to one block after compression from the file compression device 60 in response to the compression processing state monitoring unit 13 detecting the end of the compression processing of one block, and acquires the compression Based on the information relating to the subsequent one block, information for specifying the compressed one block is generated and further stored in the index file 31.

  That is, the block information acquisition unit 14 acquires the block size of one block after compression from the file compression apparatus 60, and the block position from the head of the compressed file 61 based on the acquired block size of one block after compression. Is calculated. Specifically, the block information acquisition unit 14 acquires the block size of one block after compression according to the interface with the file compression device 60 at each end of the compression process, adds the acquired block size, and compresses it. The block position from the head of the subsequent file 61 is calculated. Block_pos_1 to block_pos_n in FIG. 3 (2) indicate the block positions calculated in this way.

  Next, the block information acquisition unit 14 further stores the calculated block position from the beginning of the compressed file 61 in the index file 31. Specifically, as illustrated in FIG. 3A, the block information acquisition unit 14 associates with the index (for example, key1) and includes the block position of the block (for example, the block 61i) including the record corresponding to the index. (For example, block_pos_i) is further stored in the index file 31.

  As shown in FIG. 3A, the index file 31 is a block of a block after compression including an index (for example, key1), a delimiter code (for example, \ t), and a record corresponding to the index. Position (for example, block_pos_i). When decompressing the post-compression file 61, the block position of the post-compression block including the record corresponding to the index to be searched (for example, the post-compression block 61i including the record 1 corresponding to “key1” in FIG. 3B) Block_pos_i) is specified, only the block at the designated block position is partially decompressed, and the decompressed block 52 is generated.

  FIG. 4 is a flowchart showing the index generation processing of the index generation device 10 according to the first embodiment of the present invention. A description will be given in connection with the file compression processing of the file compression device 60.

  In step S <b> 100, the CPU of the index generation device 10 (hereinafter simply referred to as “CPU”) initializes the block position value from the beginning of the compressed file 61. Thereafter, the CPU moves the process to step S101.

  In step S101, the CPU (record delivery unit 11) reads one record of the pre-compression file 51. More specifically, the CPU reads one record from the uncompressed file 51 opened by the file processing function by the record acquisition function. The CPU moves the process to step S102.

In step S <b> 102, the CPU (record delivery unit 11) transmits the one record read in step S <b> 101 to the file compression apparatus 60 according to the interface with the file compression apparatus 60. Thereafter, the CPU moves the process to step S103.
On the other hand, the file compression apparatus 60 receives one record from the index generation apparatus 10 in step S201. Next, in step S202, the file compression apparatus 60 stores one record received from the index generation apparatus 10 in the compression buffer 62, and monitors the buffer size of the compression buffer 62.

  In step S <b> 103, the CPU (record information acquisition unit 12) assigns a record index and stores it in the index file 31. More specifically, the CPU acquires the index of the record transmitted in step S102 based on the relative position and the length of the index in the record, and associates the acquired index with the block position of the compressed block to generate the index file 31. To remember. Thereafter, the CPU moves the process to step S104.

In step S104, the CPU (compression processing state monitoring unit 13) monitors the compression processing state. More specifically, the CPU monitors the buffer size of the file information table 63 in the file compression device 60 in accordance with the interface with the file compression device 60. Thereafter, the CPU moves the process to step S105.
On the other hand, in step S203, the file compression apparatus 60 determines whether or not the buffer size has exceeded (the buffer size has become 0 or less) by monitoring the buffer size of the compression buffer 62 in step S202. If it is determined that the file compression device 60 has reached (YES), the file compression device 60 moves the control to step S204. If it is determined that it is not less than 0 (NO), the file compression device 60 moves the control to step S201. Transfer. Next, in step S204, the file compression apparatus 60 starts compression of the compression buffer 62, completes compression, creates one block after compression, and increments (+1) the block number of the file 61 after compression. . Next, in step S205, the file compression apparatus 60 determines whether or not the process is completed. If the file compression apparatus 60 determines that the process is not completed (for example, one record has been received within a predetermined time), the process proceeds to step S201. If it is determined that there is a certain record (for example, one record is not received within a certain time), the process is terminated.

  In step S105, the CPU (compression processing state monitoring unit 13) determines whether or not compression for one block has been completed. More specifically, the CPU determines whether or not the block number monitored in step S104 has increased (+1). If this determination is YES, the CPU moves the process to step S106, and if this determination is NO, the CPU moves the process to step S101.

  In step S106, the CPU (block information acquisition unit 14) acquires the compressed block size. More specifically, the CPU acquires the block size after compression from the file compression device 60 in accordance with the interface with the file compression device 60. Thereafter, the CPU moves the process to step S107.

  In step S107, the CPU (block information acquisition unit 14) adds the compressed block size to the block position. Thereafter, the CPU moves the process to step S108.

  In step S108, the CPU (record delivery unit 11) determines whether or not the compression is finished. More specifically, the CPU determines whether or not the block including the last record of the pre-compression file 51 has been compressed (the file has been terminated in step S101). If this determination is YES, the CPU ends the process, and if this determination is NO, the CPU moves the process to step S101.

  FIG. 5 is a flowchart showing a search process for searching using the index file 31 generated by the index generation device 10 according to the first embodiment of the present invention. The search process will be described as a process executed by, for example, a search apparatus (not shown) different from the index generation apparatus 10, but may be executed by the index generation apparatus 10.

In step S301, the search device searches the index file 31 using the index included in the record to be searched. Next, in step S302, the search device acquires a block position corresponding to the searched index. Next, in step S303, the search device decompresses only the blocks starting from the acquired block position among the blocks constituting the post-compression file 61. Next, in step S304, the search device searches from the decompressed block file using an index, and acquires a record to be searched. In addition, when the record to be searched spans the block, the search device also decompresses the next block and acquires the record to be searched.
As described above, the index generation device 10 can extract the index file 31 that can search the record to be searched by partially decompressing only the block including the record to be searched by the search device among the blocks constituting the post-compression file 61. Can be generated.

[Embodiment 2]
The function of the index generation device 10 according to the second embodiment will be described with reference to FIG. 1, FIG. 2, and FIG. FIG. 6 is a diagram showing an example of the index file 31 according to the second embodiment of the present invention. 6 (1) shows an example of the index file 31, and FIG. 6 (2) shows an example of the pre-compression file 51, the post-compression file 61, and the decompression block 53 partially decompressed from the post-compression file 61. Show.

  The record information acquisition unit 12 in FIG. 1 is based on the record size of the record delivered by the record delivery unit 11 and is a pre-compression block corresponding to a block after compression that includes a record to be delivered that is a block of the pre-compression file 51 that includes the record to be delivered. The offset of the record to be delivered (hereinafter referred to as the record offset) from the head of the block of the file 51 is calculated, and further stored in the index file 31 in association with the record to be delivered together with the record size.

  As shown in FIG. 6 (1), the index file 31 is a compressed block position (eg, key 1), a delimiter code (eg, \ t), and a block position after compression (including a record corresponding to the index). For example, block_pos_i), delimiter code (for example, \ t), and record offset of the uncompressed file 51 including the record corresponding to the index (for example, the uncompressed file 51 corresponding to the compressed block 61i including the record 1 to be delivered). Record offset from the beginning of the block 51i, that is, offset_1 of the decompression block 53), delimiter code (for example, \ t), and record size of the uncompressed file 51 including the record corresponding to the index (for example, record 1 to be delivered) Compressed block containing Record size of the compressed before file 51 corresponding to 61i, that is, constituted from the Length_1) of decompression block 53.

  Specifically, in FIG. 6B, the record information acquisition unit 12 starts the block (for example, block 51i) of the uncompressed file 51 corresponding to the compressed block (for example, block 61i) that includes the delivered record. The record offset from is calculated based on the record size of the record to be delivered. That is, the record information acquisition unit 12 sets the initial value of the record offset every time it is compressed to a size that overflows from the compression buffer (for example, the first block is 0, and the record is stored across blocks) Overflow size), the record size of the record to be delivered is added to the record offset, and the record offset of the record to be delivered from the head of the block of the file 51 before compression is calculated. Then, as shown in FIG. 6A, the record information acquisition unit 12 associates both the record offset (for example, offset_1) and the record size (for example, length_1) with the index of the record to be delivered (for example, key1). Further stored in the index file 31. When the record offset stored in this way is used, the search device (not shown) generates a decompression block 53 in which the compressed block 61i is decompressed from the beginning to the portion including the record to be searched. can do. A retrieval device (not shown) generates a decompression block 53 that decompresses the compressed block (for example, block 61i) from the beginning to the portion including the record to be retrieved, and searches the decompression block 53. Instead, records corresponding to the record size can be easily extracted from the end of the decompression block 53 to obtain a search result.

  FIG. 7 is a flowchart showing the index generation processing of the index generation device 10 according to the second embodiment of the present invention. A description will be given in connection with the file compression processing of the file compression device 60.

  Since step S110 is the same as step S100 of the first embodiment, a description thereof will be omitted.

  In step S111, the CPU (record delivery unit 11) reads one record of the pre-compression file 51. More specifically, the CPU reads one record from the pre-compression file 51 opened by the file processing function using the record acquisition function, and acquires the record size. Then, the CPU moves the process to step S112.

  In step S <b> 112, the CPU (record delivery unit 11) transmits the one record read in step S <b> 111 to the file compression apparatus 60 according to the interface with the file compression apparatus 60. Thereafter, the CPU moves the process to step S113.

  In step S <b> 113, the CPU (record information acquisition unit 12) stores the record index, block position, record offset, and record size in the index file 31. More specifically, the CPU acquires the index of the record transmitted in step S112 based on the relative position in the record and the length of the index. Next, the CPU stores the block position, record offset, and record size in the index file 31 in association with the record index. Next, the CPU adds the record size acquired in step S111 to the record offset and stores it. Thereafter, the CPU moves the process to step S114.

  Steps S114 to S116 are the same as steps S104 to S106 of the first embodiment, and are therefore omitted. In step S117 corresponding to step S107 in the first embodiment, the CPU adds the compressed block size to the block position and sets an initial value of the record offset. Since S118 is the same as step S108 in the first embodiment, a description thereof will be omitted.

  FIG. 8 is a flowchart showing search processing for searching using the index file 31 generated by the index generation device 10 according to the second embodiment of the present invention. The search process will be described as a process executed by, for example, a search apparatus (not shown) different from the index generation apparatus 10, but may be executed by the index generation apparatus 10.

In step S311, the search device searches the index file 31 using the index included in the record to be searched. Next, in step S312, the search device acquires a block position, a record offset, and a record size corresponding to the searched index. Next, in step S313, the search device calculates the record offset and the record size up to the portion including the record to be searched for the block after the compression at the acquired block position among the blocks constituting the post-compression file 61. Use and thaw. Next, in step S314, the search device searches the decompressed block file using an index and obtains a record to be searched. In step S314, the search device may acquire the last record of the decompressed block as a record to be searched. When the record to be searched is straddling the block, the search device also decompresses the next block using the record size.
In this way, the index generation device 10 can search by decompressing only the block including the record to be searched by the search device to the portion including the record to be searched among the blocks constituting the post-compression file 61. A file 31 can be generated.

  According to the first embodiment, the index generation device 10 sequentially delivers a plurality of records constituting the pre-compression file 51 to the file compression device 60, assigns an index of the record to be delivered, and sequentially stores it in the index file 31. Next, the index generation device 10 monitors the compression processing state in the file compression device 60, and determines the block size of one block after compression from the file compression device 60 in response to detecting the end of the compression processing of one block. Based on the acquired block size of one block after compression, the block position from the head of the post-compression file 61 of one block after compression is calculated and further stored in the index file 31. Therefore, the index generation device 10 sequentially stores the index of the record to be delivered for compression in order to read out the necessary record from the compressed file 61, and one block after compression is a block from the head of the compressed file 61. The location is further stored, and information for partially decompressing the post-compression file 61 is generated. As a result, the index generation device 10 can provide information that can specify a block to be decompressed when a predetermined record is read from the compressed file 61.

  According to the second embodiment, the index generation apparatus 10 delivers from the head of the block of the uncompressed file 51 corresponding to the block after compression that includes the delivered record that is the block of the uncompressed file 51 including the delivered record. The record offset is calculated and stored in the index file 31 in association with the record to be delivered together with the record size. Therefore, the index generation device 10 sequentially stores the index of the record to be delivered for compression in order to read out the necessary record from the compressed file 61, and one block after compression is a block from the head of the compressed file 61. In order to store the position, further store the record offset and record size of the record to be delivered from the head of the block of the uncompressed file 51, and decompress the necessary record in the corresponding block of the compressed file 61 Generate information for. As a result, the index generating apparatus 10 can provide information that can specify the block to be decompressed and the amount of data to be decompressed when a predetermined record is read from the post-compression file 61.

  In the present embodiment, the index generation device 10 is configured, but the configuration is not limited thereto. For example, the program may be configured as a computer program that is incorporated in the file compression device 60 and realizes the same function as the index generation device 10 according to an interface with the program of the file compression device 60.

  As mentioned above, although embodiment of this invention was described, this invention is not restricted to embodiment mentioned above. The effects described in the embodiments of the present invention are only the most preferable effects resulting from the present invention, and the effects of the present invention are limited to those described in the embodiments of the present invention. is not.

DESCRIPTION OF SYMBOLS 10 Index production | generation apparatus 11 Record delivery part 12 Record information acquisition part 13 Compression process status monitoring part 14 Block information acquisition part 31 Index file 51 File before compression 61 File after compression

Claims (3)

An index generation device capable of communicating with a file compression device that compresses and decompresses a file block by block,
Record delivery means for sequentially delivering a plurality of records constituting a file to be compressed to the file compression device;
Record information acquisition means for providing an index of the record to be delivered and sequentially storing the index storage means;
Compression processing status monitoring means for monitoring the compression processing status in the file compression device and detecting the end of compression processing of one block;
In response to the compression processing state monitoring means detecting the end of the compression processing of the one block, information related to the one block after compression is acquired from the file compression apparatus, and the acquired one block after compression is acquired. Block information acquisition means for generating information for specifying the one block after compression based on the information relating to the information and further storing the information in the index storage means;
An index generation device comprising:   The record information acquisition means, based on the record size of the record to be transferred, is a block of the file before compression that includes the record to be transferred and corresponds to one block after compression that includes the record to be transferred. The index generation device according to claim 1, further comprising: calculating an offset of the record to be delivered and further storing the offset in association with the record to be delivered together with a record size in the index storage unit. A method executed by an index generation device that can communicate with a file compression device that compresses and decompresses a file block by block,
A record delivery step of sequentially delivering a plurality of records constituting a file to be compressed to the file compression device;
A record information acquisition step of assigning an index of the record to be delivered and sequentially storing the index storage means;
A compression processing state monitoring step of monitoring a compression processing state in the file compression device and detecting the end of compression processing of one block;
In response to the compression processing state monitoring step detecting the end of the compression processing of the one block, information related to the one block after compression is acquired from the file compression apparatus, and the acquired one block after compression is acquired. A block information acquisition step of generating information for specifying the one block after compression based on the information related to the information and further storing the information in the index storage means;
A method comprising:

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