6.12.6 Determining the size of the user logs that are output during execution of the adbmergechunk command (variable max_user_log)
Use the following formula to determine the size of the user logs that are output during execution of the adbmergechunk command.
Formula (bytes)
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![[Figure]](GRAPHICS/F0000627.GIF)
Explanation of variables
- MERPRGLOG
-
Deletion log for the index data that is defined for the table to be processed by the merge chunk command
- MERMAKELOG
-
Creation log for the index data that is defined for the table to be processed by the merge chunk command
- MERLOCLOG
-
Location table update log
- Organization of this subsection
(1) Determining the variable MERPRGLOG
Use the following formula to determine the value of variable MERPRGLOG.
Formula (bytes)
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![[Figure]](GRAPHICS/F0000628.GIF)
Explanation of variables
- idx_num
-
Number of indexes defined for the table to be processed by the merge chunk command
- dbarea_file_num(i)
-
Number of DB area files in data DB areas that store indexes
- SGIDX(i)
-
Number of segments that store indexes
- SEGBF(i)
-
Number of segment block factors in the data DB area that stores indexes
- page_size(i)
-
Page size of the data DB area that stores indexes (bytes)
- usrlog_file_num
-
Use the following formula to determine its value.
![[Figure]](GRAPHICS/F0000629.GIF)
For details about the number of segments in a data DB area and the segment block factors, see (2) Explanation of variables in 5.8.1 Determining the total number of pages in the data DB area.
For details about the number of user log files required during execution of the adbmergechunk command, see (2) Commands for which the number of user log files needs to be estimated in 6.12.15 Determining the number of user log files.
(2) Determining the variable MERMAKELOG
Use the following formula to determine the value of variable MERMAKELOG.
Formula (bytes)
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![[Figure]](GRAPHICS/F0000630.GIF)
Explanation of variables
- n
-
Number of indexes defined for the table to be processed by the merge chunk command
- MERMAKE(i)LOG
-
Log size of the i-th index defined for the table to be processed by the merge chunk command
Use the following formula to determine its value.
- Formula (bytes)
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![[Figure]](GRAPHICS/F0000631.GIF)
- page_size(i)
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Page size of the data DB area that stores the i-th index defined for the table to be processed by the merge chunk command (bytes)
- merc_dividx_rthd
-
Use the following formula to determine the value:
↓(value-specified-for-merge-chunk-option-adb_mergechunk_rthd_num - 1) ÷ 2↓
If the merge chunk option adb_mergechunk_rthd_num is omitted, substitute the number of threads used when the merge chunk option adb_mergechunk_rthd_num is omitted. For details, see adbmergechunk (Merge Chunks) in the manual HADB Command Reference.
- DIRPGNO(i)
-
Number of pages in the management area for the i-th index defined for the table to be processed by the merge chunk command
Use the following formula to determine its value.
Formula
![[Figure]](GRAPHICS/F0000632.GIF)
- dbarea_file_num(i)
-
Number of DB area files in data DB area that stores the indexes
- SGIDX(i)
-
Maximum number of index segments to be allocated to each chunk during merge chunk processing (index rebuilding).
Use the following formula to determine its value.
Formula
![[Figure]](GRAPHICS/F0000633.GIF)
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m
Number of chunks to be merged
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CHUNKSGIDX(j)
Number of index segments to be allocated to each chunk of the index to be rebuilt
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- SEGBF(i)
-
Number of segment block factors in the data DB area that stores indexes
For details about the number of segments in a data DB area and the segment block factors, see (2) Explanation of variables in 5.8.1 Determining the total number of pages in the data DB area.
(3) Determining the variable MERLOCLOG
Use the following formula to determine the value of variable MERLOCLOG.
If the table to be processed is not an archivable multi-chunk table, substitute 0. Also, if the chunk to be processed is not archived, substitute 0.
Formula (bytes)
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![[Figure]](GRAPHICS/F0000634.GIF)
Explanation of variables
- UPDLOG
-
Determine the value from the formula in Size of user logs that are output when an UPDATE statement is executed in 6.12.7 Determining the size of the user logs that are output during database updating (variable max_user_log). Note that for some of the variables in the formula, you must substitute values that are different from the values indicated in the preceding section. The following shows the relevant variables and the values to be substituted.
- VRWLOG
-
Substitute 0.
- TIXSLOG
-
Substitute 0.
- IDXSLOG
-
To determine the value of the variable IDXSLOG, see (3) Determining the size of the B-tree index user log in 6.12.7 Determining the size of the user logs that are output during database updating (variable max_user_log). Note that for some of the variables in the formula, you must substitute values that are different from the values indicated in the preceding section. The following shows the relevant variables and the values to be substituted.
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idx_num
Substitute 1.
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IDXLOG(i)
Use the following formula to determine this value.
Formula
![[Figure]](GRAPHICS/F0000635.GIF)
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SPLITLOG(i)
Determine this value according to Formula (when the number of duplicate index keys in the update-target rows is 256 or more) in the description of the SPLITLOG(i) variable in (3) Determining the size of the B-tree index user log under 6.12.7 Determining the size of the user logs that are output during database updating (variable max_user_log).
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- LROWNUM
-
Number of archive files created by the adbarchivechunk command
Use the formula for the variable LROWNUM in (f) Determining the variable SGROWTBL (for a multi-chunk table) under (2) Explanation of variables in 5.8.1 Determining the total number of pages in the data DB area. Note that for some of the variables in the formula, you must substitute values that are different from the values indicated in the preceding section. The following shows the relevant variables and the values to be substituted.
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archive_chunk_num
Substitute 0.
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merge_chunk_num
Substitute 1.
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- upd_row_num
-
Substitute the same value as the variable LROWNUM determined before.
- SGMTLOG
-
Use the following formula to determine this value.
Formula
![[Figure]](GRAPHICS/F0000636.GIF)
- LBP
-
Use the formula for the variable LBP(i) in (f) Determining the variable SGROWTBL (for a multi-chunk table) under (2) Explanation of variables in 5.8.1 Determining the total number of pages in the data DB area. Note that for some of the variables in the formula, you must substitute values that are different from the values indicated in the preceding section. The following shows the relevant variables and the values to be substituted.
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LROWNUM
Substitute the same value as the variable LROWNUM determined before.
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- SEGSIZE
-
Segment size of the data DB area that stores the archivable multi-chunk table
Use the following formula to determine this value.
Formula (pages)
![[Figure]](GRAPHICS/F0000637.GIF)
- page_size
-
Page size of the data DB area that stores the archivable multi-chunk table (bytes)