14.2.2 Format of export options

Organization of this subsection

(1) Specification format
(2) Explanation of specification format

(1) Specification format

Options related to performance
  [set adb_export_rthd_num = number-of-processing-real-threads-to-be-used-by-adbexport-command]
  [set adb_export_scan_buff_size = table-data-scan-buffer-size]
  [set adb_export_wrktbl_blk_num = number-of-local-work-table-buffer-pages]
  [set adb_export_hashtbl_area_size = hash-table-area-size]
  [set adb_export_hashflt_area_size = hash-filter-area-size]
 
Options related to output format
  [set adb_export_order_mode = {BYTE|ISO}]

The specification rules for these export options are the same as for the server definition. For details about the specification rules for the server definition, see Syntax rules for the server definition in the HADB Setup and Operation Guide.

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(2) Explanation of specification format

(a) Options related to performance

• adb_export_rthd_num = number-of-processing-real-threads-to-be-used-by-adbexport-command

~<integer>((3 to 4,096))

Specifies the number of processing real threads to be used for executing the adbexport command.

Specification of this option is recommended. The adbexport command uses the number of processing real threads specified by this option. Therefore, specify an appropriate number of processing real threads for use by the adbexport command. For details about the processing of the adbexport command that uses processing real threads and the number of processing real threads to be used for each step, see 14.1.2 Relationships among threads used by the adbexport command.

If this option is omitted, the number of processing real threads to be used for executing the adbexport command is determined by the adb_sql_exe_max_rthd_num operand in the server definition. The following table shows the relationship between the value of this option or the adb_sql_exe_max_rthd_num operand in the server definition and the number of processing real threads used for executing the command.

Table 14‒3: Number of processing real threads used for executing the command
No.	Value in this option or in the server definition		Number of processing real threads used for executing the command
1	When this option is omitted	If the `adb_sql_exe_max_rthd_num` operand in the server definition is not specified	The default value of the `adb_sql_exe_max_rthd_num` operand in the server definition is used.
2		If a value in the range from `0` to `2` is specified in the `adb_sql_exe_max_rthd_num` operand in the server definition	--
3		If `3` or a greater value is specified for the `adb_sql_exe_max_rthd_num` operand in the server definition	The value specified for the `adb_sql_exe_max_rthd_num` operand in the server definition is used.
4	If `3` or a greater value is specified in this option		The value specified in this option is used.

Legend:: --: The adbexport command results in an error.
Note:: For details about the adb_sql_exe_max_rthd_num operand in the server definition, see Operands related to performance (set format) in the HADB Setup and Operation Guide.

• adb_export_scan_buff_size = table-data-scan-buffer-size

~<integer>((1 to 2,048))<<16>> (units: megabytes)

Specify the size (in megabytes) of the buffer to be used for retaining table data search results. A larger value can reduce overhead in searching table data.

As a guideline, specify a value equivalent to the data length in the search results times about 10,000.

For details about how to obtain data lengths in search results, see Data length of each data type in Determining the memory requirement during normal operation in Estimating the HADB server's memory requirement in Preparing Resources in the HADB Setup and Operation Guide.

Note that all the retrieval results stored in one scan buffer are exported to the same output data file.

If the specified buffer size is too small to store any data item obtained in the retrieval results, the adbexport command will result in an error.

• adb_export_wrktbl_blk_num = number-of-local-work-table-buffer-pages

~<integer>((5 to 100,000,000))

Normally, you will omit this option. When this option is omitted, the number of local work table buffer pages specified in the adb_dbbuff_wrktbl_clt_blk_num server definition operand is applied.

To minimize the execution time of an SQL statement that creates a local work table when the adbexport command is executed, specify in this option the number of local work table buffer pages. The local work table buffer allocated based on this option's value is used only when an SQL statement that creates a local work table is executed by the adbexport command. If this option is specified together with the adb_dbbuff_wrktbl_clt_blk_num server definition operand, the number of local work table buffer pages specified in this option is used when the adbexport command executes.

For details about how to estimate a value for this option, see Estimating the number of pages in the buffer for local work tables in Estimates related to work tables in Preparing Resources in the HADB Setup and Operation Guide.

The number of local work table buffer pages allocated by specifying this option cannot be changed by the adbmodbuff command. For details about the adbmodbuff command, see 35. adbmodbuff (Change Buffer).

Note: A local work table is created for each real thread that processes the SQL statement. Therefore, a local work table buffer with the number of pages specified in this option is allocated for each real thread that processes the SQL statement. For details about the SQL statements that create local work tables, see Work tables created when SQL statements are executed in Considerations when executing an SQL statement that creates work tables in Designs Related to Improvement of Application Program Performance in the HADB Application Development Guide.

• adb_export_hashtbl_area_size = hash-table-area-size

~<integer>((0 to 4,194,304)) (megabytes)

Normally, you will omit this option. If this option is omitted, the size of the hash table area specified in the adb_sql_exe_hashtbl_area_size operand in the server definition operand is applied.

To minimize the execution time of an SQL statement to which the hash retrieval is applied when the adbexport command is executed, specify in this option the size of the hash table area in megabytes. For details about estimating the value to be specified for this option, see Tuning to shorten SQL statement execution time by re-examining the hash table area size in the HADB Setup and Operation Guide.

The hash table area allocated based on this option's value is used only when an SQL statement to which hash retrieval is applied is executed by the adbexport command. If this option is specified together with the adb_sql_exe_hashtbl_area_size operand in the server definition, the size of the hash table area specified in this option is applied when the adbexport command is executed. For details about the adb_sql_exe_hashtbl_area_size operand in the server definition, see Operands related to performance in the HADB Setup and Operation Guide.

• adb_export_hashflt_area_size = hash-filter-area-size

~<integer>((0 to 419,430)) (megabytes)

Normally, you will omit this option. The value that is applied when this option is omitted varies depending on whether the adb_export_hashtbl_area_size export option is specified.

If the adb_export_hashtbl_area_size export option is specified:

The following value is applied.

↑value-of-the-adb_export_hashtbl_area_size-export-option÷10↑

If the adb_export_hashtbl_area_size export option is not specified:

The value of the adb_sql_exe_hashflt_area_size operand in the server definition is applied.

To minimize the execution time of an SQL statement to which the hash filter is applied when the adbexport command is executed, specify in this option the size of the hash filter area in megabytes. For details about estimating the value to be specified for this option, see Tuning to shorten SQL statement execution time by re-examining the hash filter area size in the HADB Setup and Operation Guide.

The hash filter area allocated based on this option's value is used only when an SQL statement to which hash filters are applied is executed by the adbexport command. If this option is specified together with the adb_sql_exe_hashflt_area_size operand in the server definition, the size of the hash filter area specified in this option is applied when the adbexport command is executed. For details about the adb_sql_exe_hashflt_area_size operand in the server definition, see Operands related to performance in the HADB Setup and Operation Guide.

(b) Options related to output results

• adb_export_order_mode = {BYTE|ISO}

Specifies the sort order for character string data when the ORDER BY clause is specified in the SQL statement file.

Specify this option when you want to export the retrieval results in a different sort order than the order specified in the adb_sql_order_mode server definition operand.

If this option is omitted and an ORDER BY clause is specified in the SQL statement file, the retrieval results are exported in the order specified in the adb_sql_order_mode server definition operand. For details about the adb_sql_order_mode operand, see the topic Operands related to SQL statements (set format) in Detailed descriptions of the server definition operands in Designing the Server Definition in the HADB Setup and Operation Guide.

BYTE: Output character string data by bytecode.
ISO: Output character string data by sort code (ISO/IEC 14651:2011 compliance). Note that ISO cannot be specified when SJIS is specified in the HADB server's ADBLANG environment variable.

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