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8.2.42 DUMP 2399

Code Symbol Kernel Block(s)
node_id 2399 [none] DBLQH

Description.  Similarly to DUMP 2398, this command dumps information about free space in log part files for the data node with the node ID node_id. Unlike the case with DUMP 2398, the dump is written to the cluster log, and includes a figure for the percentage of free space remaining in the redo log.

Sample Output. 

ndb_mgm> 6 DUMP 2399
Sending dump signal with data:
0x0000095f

(Written to cluster log:)

2014-10-15 13:39:50 [MgmtSrvr] INFO     -- Node 5: Logpart: 0 head=[ file: 0 mbyte: 2 ] tail=[ file: 0 mbyte: 2 ] total mb: 256 free mb: 256 free%: 100
2014-10-15 13:39:50 [MgmtSrvr] INFO     -- Node 5: Logpart: 1 head=[ file: 0 mbyte: 2 ] tail=[ file: 0 mbyte: 2 ] total mb: 256 free mb: 256 free%: 100
2014-10-15 13:39:50 [MgmtSrvr] INFO     -- Node 5: Logpart: 2 head=[ file: 0 mbyte: 2 ] tail=[ file: 0 mbyte: 2 ] total mb: 256 free mb: 256 free%: 100
2014-10-15 13:39:50 [MgmtSrvr] INFO     -- Node 5: Logpart: 3 head=[ file: 0 mbyte: 2 ] tail=[ file: 0 mbyte: 2 ] total mb: 256 free mb: 256 free%: 100
2014-10-15 13:39:50 [MgmtSrvr] INFO     -- Node 6: Logpart: 0 head=[ file: 0 mbyte: 2 ] tail=[ file: 0 mbyte: 2 ] total mb: 256 free mb: 256 free%: 100
2014-10-15 13:39:50 [MgmtSrvr] INFO     -- Node 6: Logpart: 1 head=[ file: 0 mbyte: 2 ] tail=[ file: 0 mbyte: 2 ] total mb: 256 free mb: 256 free%: 100
2014-10-15 13:39:50 [MgmtSrvr] INFO     -- Node 6: Logpart: 2 head=[ file: 0 mbyte: 2 ] tail=[ file: 0 mbyte: 2 ] total mb: 256 free mb: 256 free%: 100
2014-10-15 13:39:50 [MgmtSrvr] INFO     -- Node 6: Logpart: 3 head=[ file: 0 mbyte: 2 ] tail=[ file: 0 mbyte: 2 ] total mb: 256 free mb: 256 free%: 100

Additional Information.  Each line of the output uses the following format (shown here split across two lines for legibility):

timestamp [MgmtSrvr] INFO     -- Node node_id: Logpart: part_no head=[ file: start_file_no mbyte: start_pos ]
tail=[ file: end_file_no mbyte: end_pos ] total mb: total_space free mb: free_space free%: free_pct

timestamp shows when the command was executed by data node node_id. A data node's redo log is divided into four parts. which part is indicated by part_no (always a number between 0 and 3 inclusive). The parts are stored in the data node file system directories named D8, D9, D10, and D11; redo log part 0 is stored in D8, part 1 in D9, and so on. Within each of these four directories is a DBLQH subdirectory containing NoOfFragmentLogFiles fragment log files. The default value for NoOfFragmentLogFiles is 16. The default size of each of these files is 16 MB; this can be changed by setting the FragmentLogFileSize configuration parameter. (See Section 8.1.1.2, “MySQL Cluster Data Node File System Directory Files”, for more information about the fragment log files.)

start_file_no indicates the number of the file and start_pos the point inside this file in which the redo log starts; for the example just shown, since part_no is 0, this means that the redo log starts at approximately 12 MB from the end of the file D8/DBLQH/S6.FragLog.

Similarly, end_file_no corresponds to the number of the file and end_pos to the point within that file where the redo log ends. Thus, in the previous example, the redo log's end point comes approximately 10 MB from the end of D8/DBLQH/S6.FragLog.

total_space shows the total amount of space reserved for part part_no of the redo log. This is equal to NoOfFragmentLogFiles * FragmentLogFileSize; by default this is 16 times 16 MB, or 256 MB. free_space shows the amount remaining. The amount used is equal to total_space - free_space; in this example, this is 256 - 254 = 2 MB. free_pct shows the ratio of free_space to total_space, expressed as whole-number percentage. In the example just shown, this is equal to 100 * (254 / 256), or approximately 99 percent.


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