diff options
Diffstat (limited to 'src/mongo/db/storage/mmap_v1/record.h')
| -rw-r--r-- | src/mongo/db/storage/mmap_v1/record.h | 211 |
1 files changed, 127 insertions, 84 deletions
diff --git a/src/mongo/db/storage/mmap_v1/record.h b/src/mongo/db/storage/mmap_v1/record.h index 38c0cfd7085..0f3f9ebcdd4 100644 --- a/src/mongo/db/storage/mmap_v1/record.h +++ b/src/mongo/db/storage/mmap_v1/record.h @@ -37,98 +37,141 @@ namespace mongo { - class DeletedRecord; - - /* MmapV1RecordHeader is a record in a datafile. DeletedRecord is similar but for deleted space. - - *11:03:20 AM) dm10gen: regarding extentOfs... - (11:03:42 AM) dm10gen: an extent is a continugous disk area, which contains many Records and DeleteRecords - (11:03:56 AM) dm10gen: a DiskLoc has two pieces, the fileno and ofs. (64 bit total) - (11:04:16 AM) dm10gen: to keep the headesr small, instead of storing a 64 bit ptr to the full extent address, we keep just the offset - (11:04:29 AM) dm10gen: we can do this as we know the record's address, and it has the same fileNo - (11:04:33 AM) dm10gen: see class DiskLoc for more info - (11:04:43 AM) dm10gen: so that is how MmapV1RecordHeader::myExtent() works - (11:04:53 AM) dm10gen: on an alloc(), when we build a new MmapV1RecordHeader, we must populate its extentOfs then - */ +class DeletedRecord; + +/* MmapV1RecordHeader is a record in a datafile. DeletedRecord is similar but for deleted space. + +*11:03:20 AM) dm10gen: regarding extentOfs... +(11:03:42 AM) dm10gen: an extent is a continugous disk area, which contains many Records and DeleteRecords +(11:03:56 AM) dm10gen: a DiskLoc has two pieces, the fileno and ofs. (64 bit total) +(11:04:16 AM) dm10gen: to keep the headesr small, instead of storing a 64 bit ptr to the full extent address, we keep just the offset +(11:04:29 AM) dm10gen: we can do this as we know the record's address, and it has the same fileNo +(11:04:33 AM) dm10gen: see class DiskLoc for more info +(11:04:43 AM) dm10gen: so that is how MmapV1RecordHeader::myExtent() works +(11:04:53 AM) dm10gen: on an alloc(), when we build a new MmapV1RecordHeader, we must populate its extentOfs then +*/ #pragma pack(1) - class MmapV1RecordHeader { - public: - enum HeaderSizeValue { HeaderSize = 16 }; - - int lengthWithHeaders() const { return _lengthWithHeaders; } - int& lengthWithHeaders() { return _lengthWithHeaders; } - - int extentOfs() const { return _extentOfs; } - int& extentOfs() { return _extentOfs; } - - int nextOfs() const { return _nextOfs; } - int& nextOfs() { return _nextOfs; } - - int prevOfs() const { return _prevOfs; } - int& prevOfs() { return _prevOfs; } - - const char* data() const { return _data; } - char* data() { return _data; } - - // XXX remove - const char* dataNoThrowing() const { return _data; } - char* dataNoThrowing() { return _data; } - - int netLength() const { return _netLength(); } - - /* use this when a record is deleted. basically a union with next/prev fields */ - DeletedRecord& asDeleted() { return *((DeletedRecord*) this); } - - DiskLoc myExtentLoc(const DiskLoc& myLoc) const { return DiskLoc(myLoc.a(), extentOfs() ); } - - struct NP { - int nextOfs; - int prevOfs; - }; - - NP* np() { return (NP*) &_nextOfs; } - - RecordData toRecordData() const { return RecordData(_data, _netLength()); } - - private: - - int _netLength() const { return _lengthWithHeaders - HeaderSize; } - - int _lengthWithHeaders; - int _extentOfs; - int _nextOfs; - int _prevOfs; - - /** be careful when referencing this that your write intent was correct */ - char _data[4]; - - public: - static bool MemoryTrackingEnabled; - +class MmapV1RecordHeader { +public: + enum HeaderSizeValue { HeaderSize = 16 }; + + int lengthWithHeaders() const { + return _lengthWithHeaders; + } + int& lengthWithHeaders() { + return _lengthWithHeaders; + } + + int extentOfs() const { + return _extentOfs; + } + int& extentOfs() { + return _extentOfs; + } + + int nextOfs() const { + return _nextOfs; + } + int& nextOfs() { + return _nextOfs; + } + + int prevOfs() const { + return _prevOfs; + } + int& prevOfs() { + return _prevOfs; + } + + const char* data() const { + return _data; + } + char* data() { + return _data; + } + + // XXX remove + const char* dataNoThrowing() const { + return _data; + } + char* dataNoThrowing() { + return _data; + } + + int netLength() const { + return _netLength(); + } + + /* use this when a record is deleted. basically a union with next/prev fields */ + DeletedRecord& asDeleted() { + return *((DeletedRecord*)this); + } + + DiskLoc myExtentLoc(const DiskLoc& myLoc) const { + return DiskLoc(myLoc.a(), extentOfs()); + } + + struct NP { + int nextOfs; + int prevOfs; }; -#pragma pack() - - // TODO: this probably moves to record_store.h - class DeletedRecord { - public: - int lengthWithHeaders() const { return _lengthWithHeaders; } - int& lengthWithHeaders() { return _lengthWithHeaders; } + NP* np() { + return (NP*)&_nextOfs; + } - int extentOfs() const { return _extentOfs; } - int& extentOfs() { return _extentOfs; } + RecordData toRecordData() const { + return RecordData(_data, _netLength()); + } - // TODO: we need to not const_cast here but problem is DiskLoc::writing - DiskLoc& nextDeleted() const { return const_cast<DiskLoc&>(_nextDeleted); } +private: + int _netLength() const { + return _lengthWithHeaders - HeaderSize; + } - private: - int _lengthWithHeaders; + int _lengthWithHeaders; + int _extentOfs; + int _nextOfs; + int _prevOfs; - int _extentOfs; + /** be careful when referencing this that your write intent was correct */ + char _data[4]; - DiskLoc _nextDeleted; - }; +public: + static bool MemoryTrackingEnabled; +}; +#pragma pack() - BOOST_STATIC_ASSERT( 16 == sizeof(DeletedRecord) ); +// TODO: this probably moves to record_store.h +class DeletedRecord { +public: + int lengthWithHeaders() const { + return _lengthWithHeaders; + } + int& lengthWithHeaders() { + return _lengthWithHeaders; + } + + int extentOfs() const { + return _extentOfs; + } + int& extentOfs() { + return _extentOfs; + } + + // TODO: we need to not const_cast here but problem is DiskLoc::writing + DiskLoc& nextDeleted() const { + return const_cast<DiskLoc&>(_nextDeleted); + } + +private: + int _lengthWithHeaders; + + int _extentOfs; + + DiskLoc _nextDeleted; +}; + +BOOST_STATIC_ASSERT(16 == sizeof(DeletedRecord)); } // namespace mongo |