Movatterモバイル変換

Description.  Similarly toDUMP 2398, this command dumps information about free space in log part files for the data node with the node IDnode_id. Unlike the case withDUMP 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 2399Sending 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%: 1002014-10-15 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%: 1002014-10-15 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%: 1002014-10-15 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%: 1002014-10-15 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%: 1002014-10-15 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%: 1002014-10-15 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%: 1002014-10-15 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     -- Nodenode_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 nodenode_id. A data node's redo log is divided into four parts. which part is indicated bypart_no (always a number between 0 and 3 inclusive). The parts are stored in the data node file system directories namedD8,D9,D10, andD11; redo log part 0 is stored inD8, part 1 inD9, and so on. Within each of these four directories is aDBLQH subdirectory containingNoOfFragmentLogFiles fragment log files. The default value forNoOfFragmentLogFiles is 16. The default size of each of these files is 16 MB; this can be changed by setting theFragmentLogFileSize configuration parameter. (SeeSection 1.1.2, “NDB Cluster Data Node File System Directory”, for more information about the fragment log files.)

start_file_no indicates the number of the file andstart_pos the point inside this file in which the redo log starts; for the example just shown, sincepart_no is 0, this means that the redo log starts at approximately 12 MB from the end of the fileD8/DBLQH/S6.FragLog.

Similarly,end_file_no corresponds to the number of the file andend_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 ofD8/DBLQH/S6.FragLog.

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