The onstat -X command displays the sharers and waiters for buffers.
Buffers (Access) address owner flags pagenum memaddr nslots pgflgs scount waiter Buffer pool page size: 2048 47 modified, 3000000 total, 4194304 hash buckets, 2048 buffer size Buffer pool page size: 16384 637 modified, 500000 total, 524288 hash buckets, 16384 buffer size
Heading | Description | Format | See Also |
---|---|---|---|
address | Address of the buffer header in the Resident Memory buffer pool. | onstat -b | |
owner | The address of the userthread currently accessing this buffer. This address corresponds to the address field given by the onstat -u command. | onstat -u | |
flgs | Flags identifying the current status of the buffer page
0x01 Modified Data 0x02 Data 0x04 LRU 0x08 Error 0x20 LRU AIO write in progress 0x40 Chunk write in progress 0x80 Buffer is/will be result of read-ahead 0x100 Cleaner assigned to LRU 0x200 Buffer should avoid bf_check calls 0x400 Do log flush before writing page 0x800 Buffer has been ‘buff’-checked 0x8000 Buffer has been pinned 0x10000 Buffer modified by fuzzy operation 0x20000 Use aging of buffer on LRU 0x40000 Don’t use buffer priorities |
onstat -b | |
pagenum | The physical page number of this page on disk | ||
memaddr | The buffer memory address | ||
nslots | The number of slot table entries (i.e., rows or row portions) on this page. | ||
pgflgs | Describes the page type
0x01 Data Page 0x02 Partition Page 0x04 Bitmap Page 0x08 Chunk Free List Page 0x09 Remainder Data Page 0x0b Partition Resident BLOB Page 0x0c BLOBSpace Resident BLOB Page 0x0d BLOB Chunk Free List Bitmap Page 0x0e BLOB Chunk BLOB Map Page 0x10 B+ Tree Node Page 0x20 B+ Tree Root Node Page 0x40 B+ Tree Branch Node Page 0x80 B+ Tree Leaf Node Page 0x100 Logical Log Page 0x200 Last Page of Logical Log 0x400 Sync Page of Logical Log 0x800 Physical Log Page 0x1000 Root Reserved Page 0x2000 No Physical Logging Required 0x4000 No Physical Logging Required (load-time) 0x8000 B-Tree Leaf with deleted entries 0x20 Secondary partition header (w/0x02) 0x40 Alter description partition header (w/0x02) 0x80 Key descriptor partition page (w/0x02) 0x80 Generic page 0x4000 Do not allocate a row without checking |
onstat -b | |
scount | A count of the number of threads sharing this buffer. | ||
waiter | A list of the threads waiting for this buffer. |
Label | Description | See Also |
---|---|---|
modified | The total number of buffers in the pool that have been modified since the last buffer flush (e.g., from a checkpoint) | onstat -R |
total | The total number of buffers as allocated by the BUFFERS parameter in the configuration file. | onstat -R |
hash buckets | The number of hash buckets created to track the pages placed into the buffer pool. | onstat -h |
buffer size | The size of an individual buffer. This is determined at port time and is not configurable. | onstat -R |
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