A cache when reading files over the network.
A caching system to speed up network I/O, i.e. when there is no operating system caching support (like the buffer cache for local disk I/O). The cache makes sure that every I/O is done with a (large) fixed length buffer thereby avoiding many small I/O's. Currently the read cache system is used by the classes TNetFile, TXNetFile and TWebFile (via TFile::ReadBuffers()). When processing TTree, TChain, a specialized class TTreeCache that derives from this class is automatically created.
Definition at line 22 of file TFileCacheRead.h.
Public Member Functions | |
TFileCacheRead () | |
Default Constructor. | |
TFileCacheRead (TFile *file, Int_t buffersize, TObject *tree=nullptr) | |
Creates a TFileCacheRead data structure. | |
virtual | ~TFileCacheRead () |
Destructor. | |
virtual Int_t | AddBranch (const char *, Bool_t=kFALSE) |
virtual Int_t | AddBranch (TBranch *, Bool_t=kFALSE) |
virtual void | AddNoCacheBytesRead (Long64_t len) |
virtual void | AddNoCacheReadCalls (Int_t reads) |
virtual void | Close (Option_t *option="") |
Close out any threads or asynchronous fetches used by the underlying implementation. | |
virtual Int_t | GetBufferSize () const |
virtual Long64_t | GetBytesRead () const |
virtual Long64_t | GetBytesReadExtra () const |
TFile * | GetFile () const |
virtual Long64_t | GetNoCacheBytesRead () const |
virtual Int_t | GetNoCacheReadCalls () const |
Int_t | GetNseek () const |
Int_t | GetNtot () const |
Long64_t | GetPrefetchedBlocks () const |
virtual TFilePrefetch * | GetPrefetchObj () |
virtual Int_t | GetReadCalls () const |
virtual Int_t | GetUnzipBuffer (char **, Long64_t, Int_t, Bool_t *) |
virtual Bool_t | IsAsyncReading () const |
virtual Bool_t | IsEnablePrefetching () const |
virtual Bool_t | IsLearning () const |
virtual Int_t | LearnBranch (TBranch *, Bool_t=kFALSE) |
virtual void | Prefetch (Long64_t pos, Int_t len) |
Add block of length len at position pos in the list of blocks to be prefetched. | |
virtual void | Print (Option_t *option="") const |
Print cache statistics. | |
virtual Int_t | ReadBuffer (char *buf, Long64_t pos, Int_t len) |
Read buffer at position pos. | |
virtual Int_t | ReadBufferExt (char *buf, Long64_t pos, Int_t len, Int_t &loc) |
virtual Int_t | ReadBufferExtNormal (char *buf, Long64_t pos, Int_t len, Int_t &loc) |
Base function for ReadBuffer. | |
virtual Int_t | ReadBufferExtPrefetch (char *buf, Long64_t pos, Int_t len, Int_t &loc) |
prefetch the first block | |
virtual void | SecondPrefetch (Long64_t, Int_t) |
virtual void | SecondSort () |
Sort buffers to be prefetched in increasing order of positions. | |
virtual Int_t | SetBufferSize (Int_t buffersize) |
Sets the buffer size. | |
virtual void | SetEnablePrefetching (Bool_t setPrefetching=kFALSE) |
Set the prefetching mode of this file. | |
virtual void | SetFile (TFile *file, TFile::ECacheAction action=TFile::kDisconnect) |
Set the file using this cache and reset the current blocks (if any). | |
virtual void | SetSkipZip (Bool_t=kTRUE) |
virtual void | Sort () |
Sort buffers to be prefetched in increasing order of positions. | |
virtual void | WaitFinishPrefetch () |
Public Member Functions inherited from TObject | |
TObject () | |
TObject constructor. | |
TObject (const TObject &object) | |
TObject copy ctor. | |
virtual | ~TObject () |
TObject destructor. | |
void | AbstractMethod (const char *method) const |
Use this method to implement an "abstract" method that you don't want to leave purely abstract. | |
virtual void | AppendPad (Option_t *option="") |
Append graphics object to current pad. | |
virtual void | Browse (TBrowser *b) |
Browse object. May be overridden for another default action. | |
ULong_t | CheckedHash () |
Check and record whether this class has a consistent Hash/RecursiveRemove setup (*) and then return the regular Hash value for this object. | |
virtual const char * | ClassName () const |
Returns name of class to which the object belongs. | |
virtual void | Clear (Option_t *="") |
virtual TObject * | Clone (const char *newname="") const |
Make a clone of an object using the Streamer facility. | |
virtual Int_t | Compare (const TObject *obj) const |
Compare abstract method. | |
virtual void | Copy (TObject &object) const |
Copy this to obj. | |
virtual void | Delete (Option_t *option="") |
Delete this object. | |
virtual Int_t | DistancetoPrimitive (Int_t px, Int_t py) |
Computes distance from point (px,py) to the object. | |
virtual void | Draw (Option_t *option="") |
Default Draw method for all objects. | |
virtual void | DrawClass () const |
Draw class inheritance tree of the class to which this object belongs. | |
virtual TObject * | DrawClone (Option_t *option="") const |
Draw a clone of this object in the current selected pad for instance with: gROOT->SetSelectedPad(gPad) . | |
virtual void | Dump () const |
Dump contents of object on stdout. | |
virtual void | Error (const char *method, const char *msgfmt,...) const |
Issue error message. | |
virtual void | Execute (const char *method, const char *params, Int_t *error=0) |
Execute method on this object with the given parameter string, e.g. | |
virtual void | Execute (TMethod *method, TObjArray *params, Int_t *error=0) |
Execute method on this object with parameters stored in the TObjArray. | |
virtual void | ExecuteEvent (Int_t event, Int_t px, Int_t py) |
Execute action corresponding to an event at (px,py). | |
virtual void | Fatal (const char *method, const char *msgfmt,...) const |
Issue fatal error message. | |
virtual TObject * | FindObject (const char *name) const |
Must be redefined in derived classes. | |
virtual TObject * | FindObject (const TObject *obj) const |
Must be redefined in derived classes. | |
virtual Option_t * | GetDrawOption () const |
Get option used by the graphics system to draw this object. | |
virtual const char * | GetIconName () const |
Returns mime type name of object. | |
virtual const char * | GetName () const |
Returns name of object. | |
virtual char * | GetObjectInfo (Int_t px, Int_t py) const |
Returns string containing info about the object at position (px,py). | |
virtual Option_t * | GetOption () const |
virtual const char * | GetTitle () const |
Returns title of object. | |
virtual UInt_t | GetUniqueID () const |
Return the unique object id. | |
virtual Bool_t | HandleTimer (TTimer *timer) |
Execute action in response of a timer timing out. | |
virtual ULong_t | Hash () const |
Return hash value for this object. | |
Bool_t | HasInconsistentHash () const |
Return true is the type of this object is known to have an inconsistent setup for Hash and RecursiveRemove (i.e. | |
virtual void | Info (const char *method, const char *msgfmt,...) const |
Issue info message. | |
virtual Bool_t | InheritsFrom (const char *classname) const |
Returns kTRUE if object inherits from class "classname". | |
virtual Bool_t | InheritsFrom (const TClass *cl) const |
Returns kTRUE if object inherits from TClass cl. | |
virtual void | Inspect () const |
Dump contents of this object in a graphics canvas. | |
void | InvertBit (UInt_t f) |
Bool_t | IsDestructed () const |
IsDestructed. | |
virtual Bool_t | IsEqual (const TObject *obj) const |
Default equal comparison (objects are equal if they have the same address in memory). | |
virtual Bool_t | IsFolder () const |
Returns kTRUE in case object contains browsable objects (like containers or lists of other objects). | |
R__ALWAYS_INLINE Bool_t | IsOnHeap () const |
virtual Bool_t | IsSortable () const |
R__ALWAYS_INLINE Bool_t | IsZombie () const |
virtual void | ls (Option_t *option="") const |
The ls function lists the contents of a class on stdout. | |
void | MayNotUse (const char *method) const |
Use this method to signal that a method (defined in a base class) may not be called in a derived class (in principle against good design since a child class should not provide less functionality than its parent, however, sometimes it is necessary). | |
virtual Bool_t | Notify () |
This method must be overridden to handle object notification. | |
void | Obsolete (const char *method, const char *asOfVers, const char *removedFromVers) const |
Use this method to declare a method obsolete. | |
void | operator delete (void *ptr) |
Operator delete. | |
void | operator delete[] (void *ptr) |
Operator delete []. | |
void * | operator new (size_t sz) |
void * | operator new (size_t sz, void *vp) |
void * | operator new[] (size_t sz) |
void * | operator new[] (size_t sz, void *vp) |
TObject & | operator= (const TObject &rhs) |
TObject assignment operator. | |
virtual void | Paint (Option_t *option="") |
This method must be overridden if a class wants to paint itself. | |
virtual void | Pop () |
Pop on object drawn in a pad to the top of the display list. | |
virtual Int_t | Read (const char *name) |
Read contents of object with specified name from the current directory. | |
virtual void | RecursiveRemove (TObject *obj) |
Recursively remove this object from a list. | |
void | ResetBit (UInt_t f) |
virtual void | SaveAs (const char *filename="", Option_t *option="") const |
Save this object in the file specified by filename. | |
virtual void | SavePrimitive (std::ostream &out, Option_t *option="") |
Save a primitive as a C++ statement(s) on output stream "out". | |
void | SetBit (UInt_t f) |
void | SetBit (UInt_t f, Bool_t set) |
Set or unset the user status bits as specified in f. | |
virtual void | SetDrawOption (Option_t *option="") |
Set drawing option for object. | |
virtual void | SetUniqueID (UInt_t uid) |
Set the unique object id. | |
virtual void | SysError (const char *method, const char *msgfmt,...) const |
Issue system error message. | |
R__ALWAYS_INLINE Bool_t | TestBit (UInt_t f) const |
Int_t | TestBits (UInt_t f) const |
virtual void | UseCurrentStyle () |
Set current style settings in this object This function is called when either TCanvas::UseCurrentStyle or TROOT::ForceStyle have been invoked. | |
virtual void | Warning (const char *method, const char *msgfmt,...) const |
Issue warning message. | |
virtual Int_t | Write (const char *name=0, Int_t option=0, Int_t bufsize=0) |
Write this object to the current directory. | |
virtual Int_t | Write (const char *name=0, Int_t option=0, Int_t bufsize=0) const |
Write this object to the current directory. | |
Protected Member Functions | |
void | SetEnablePrefetchingImpl (Bool_t setPrefetching=kFALSE) |
TFileCacheRead implementation of SetEnablePrefetching. | |
Protected Member Functions inherited from TObject | |
virtual void | DoError (int level, const char *location, const char *fmt, va_list va) const |
Interface to ErrorHandler (protected). | |
void | MakeZombie () |
Protected Attributes | |
Bool_t | fAsyncReading |
Bool_t | fBIsSorted |
Bool_t | fBIsTransferred |
Int_t * | fBLen |
[fBNb] | |
Int_t | fBNb |
Int_t | fBNseek |
Int_t | fBNtot |
Long64_t * | fBPos |
[fBNb] | |
Long64_t * | fBSeek |
[fBNseek] | |
Int_t * | fBSeekIndex |
[fBNseek] | |
Int_t * | fBSeekLen |
[fBNseek] | |
Int_t * | fBSeekPos |
[fBNseek] | |
Int_t | fBSeekSize |
Long64_t * | fBSeekSort |
[fBNseek] | |
Int_t * | fBSeekSortLen |
[fBNseek] | |
char * | fBuffer |
[fBufferSize] buffer of contiguous prefetched blocks | |
Int_t | fBufferLen |
Current buffer length (<= fBufferSize) | |
Int_t | fBufferSize |
Allocated size of fBuffer (at a given time) | |
Int_t | fBufferSizeMin |
Original size of fBuffer. | |
Long64_t | fBytesRead |
Number of bytes read for this cache. | |
Long64_t | fBytesReadExtra |
Number of extra bytes (overhead) read by the readahead buffer. | |
Bool_t | fEnablePrefetching |
reading by prefetching asynchronously | |
TFile * | fFile |
Pointer to file. | |
Bool_t | fIsSorted |
True if fSeek array is sorted. | |
Bool_t | fIsTransferred |
True when fBuffer contains something valid. | |
Int_t * | fLen |
[fNb] Length of long buffers | |
Int_t | fNb |
Number of long buffers. | |
Long64_t | fNoCacheBytesRead |
Number of bytes read by basket to fill cached tree. | |
Int_t | fNoCacheReadCalls |
Number of read calls by basket to fill cached tree. | |
Int_t | fNseek |
Number of blocks to be prefetched. | |
Int_t | fNtot |
Total size of prefetched blocks. | |
Long64_t * | fPos |
[fNb] start of long buffers | |
TFilePrefetch * | fPrefetch |
! Object that does the asynchronous reading in another thread | |
Long64_t | fPrefetchedBlocks |
Number of blocks prefetched. | |
Int_t | fReadCalls |
Number of read calls for this cache. | |
Long64_t * | fSeek |
[fNseek] Position on file of buffers to be prefetched | |
Int_t * | fSeekIndex |
[fNseek] sorted index table of fSeek | |
Int_t * | fSeekLen |
[fNseek] Length of buffers to be prefetched | |
Int_t * | fSeekPos |
[fNseek] Position of sorted blocks in fBuffer | |
Int_t | fSeekSize |
Allocated size of fSeek. | |
Long64_t * | fSeekSort |
[fNseek] Position on file of buffers to be prefetched (sorted) | |
Int_t * | fSeekSortLen |
[fNseek] Length of buffers to be prefetched (sorted) | |
Private Member Functions | |
TFileCacheRead (const TFileCacheRead &)=delete | |
TFileCacheRead & | operator= (const TFileCacheRead &)=delete |
Additional Inherited Members | |
Public Types inherited from TObject | |
enum | { kIsOnHeap = 0x01000000 , kNotDeleted = 0x02000000 , kZombie = 0x04000000 , kInconsistent = 0x08000000 , kBitMask = 0x00ffffff } |
enum | { kSingleKey = BIT(0) , kOverwrite = BIT(1) , kWriteDelete = BIT(2) } |
enum | EDeprecatedStatusBits { kObjInCanvas = BIT(3) } |
enum | EStatusBits { kCanDelete = BIT(0) , kMustCleanup = BIT(3) , kIsReferenced = BIT(4) , kHasUUID = BIT(5) , kCannotPick = BIT(6) , kNoContextMenu = BIT(8) , kInvalidObject = BIT(13) } |
Static Public Member Functions inherited from TObject | |
static Longptr_t | GetDtorOnly () |
Return destructor only flag. | |
static Bool_t | GetObjectStat () |
Get status of object stat flag. | |
static void | SetDtorOnly (void *obj) |
Set destructor only flag. | |
static void | SetObjectStat (Bool_t stat) |
Turn on/off tracking of objects in the TObjectTable. | |
Protected Types inherited from TObject | |
enum | { kOnlyPrepStep = BIT(3) } |
#include <TFileCacheRead.h>
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TFileCacheRead::TFileCacheRead | ( | ) |
Default Constructor.
Definition at line 40 of file TFileCacheRead.cxx.
Creates a TFileCacheRead data structure.
Definition at line 92 of file TFileCacheRead.cxx.
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Destructor.
Definition at line 159 of file TFileCacheRead.cxx.
Reimplemented in TTreeCache, and TTreeCacheUnzip.
Definition at line 84 of file TFileCacheRead.h.
Reimplemented in TTreeCacheUnzip, and TTreeCache.
Definition at line 83 of file TFileCacheRead.h.
Definition at line 85 of file TFileCacheRead.h.
Definition at line 86 of file TFileCacheRead.h.
Close out any threads or asynchronous fetches used by the underlying implementation.
This is called by TFile::Close to prevent usage of the file handles after the closing of the file.
Definition at line 188 of file TFileCacheRead.cxx.
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Definition at line 88 of file TFileCacheRead.h.
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Definition at line 89 of file TFileCacheRead.h.
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Definition at line 91 of file TFileCacheRead.h.
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Definition at line 92 of file TFileCacheRead.h.
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Definition at line 90 of file TFileCacheRead.h.
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Definition at line 96 of file TFileCacheRead.h.
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Definition at line 93 of file TFileCacheRead.h.
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Definition at line 94 of file TFileCacheRead.h.
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Definition at line 98 of file TFileCacheRead.h.
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Definition at line 683 of file TFileCacheRead.cxx.
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Definition at line 95 of file TFileCacheRead.h.
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Reimplemented in TTreeCacheUnzip.
Definition at line 97 of file TFileCacheRead.h.
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inlinevirtual |
Definition at line 99 of file TFileCacheRead.h.
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Definition at line 101 of file TFileCacheRead.h.
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Reimplemented in TTreeCache.
Definition at line 102 of file TFileCacheRead.h.
Reimplemented in TTreeCache.
Definition at line 103 of file TFileCacheRead.h.
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Add block of length len at position pos in the list of blocks to be prefetched.
If pos <= 0 the current blocks (if any) are reset.
Definition at line 201 of file TFileCacheRead.cxx.
Print cache statistics.
The format is: ******TreeCache statistics for file: cms2.root ****** Reading............................: 72761843 bytes in 7 transactions Readahead..........................: 256000 bytes with overhead = 0 bytes Average transaction................: 10394.549000 Kbytes Number of blocks in current cache..: 210, total size: 6280352
If option = "a" the list of blocks in the cache is printed NB: this function is automatically called by TTreeCache::Print
Reimplemented from TObject.
Reimplemented in TTreeCache, and TTreeCacheUnzip.
Definition at line 325 of file TFileCacheRead.cxx.
Read buffer at position pos.
If pos is in the list of prefetched blocks read from fBuffer, otherwise need to make a normal read from file. Returns -1 in case of read error, 0 in case not in cache, 1 in case read from cache.
Reimplemented in TTreeCache.
Definition at line 363 of file TFileCacheRead.cxx.
Reimplemented in TTreeCacheUnzip.
Definition at line 381 of file TFileCacheRead.cxx.
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Base function for ReadBuffer.
Also gives out the position of the block in the internal buffer. This helps TTreeCacheUnzip to avoid doing twice the binary search.
Definition at line 453 of file TFileCacheRead.cxx.
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prefetch the first block
Definition at line 393 of file TFileCacheRead.cxx.
Definition at line 258 of file TFileCacheRead.cxx.
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Sort buffers to be prefetched in increasing order of positions.
Merge consecutive blocks if necessary.
Definition at line 629 of file TFileCacheRead.cxx.
Sets the buffer size.
If the current prefetch list is too large to fit in the new buffer some or all of the prefetch blocks are dropped. The requested buffersize must be greater than zero. Return values:
Reimplemented in TTreeCache, and TTreeCacheUnzip.
Definition at line 709 of file TFileCacheRead.cxx.
Set the prefetching mode of this file.
If 'setPrefetching', enable the asynchronous prefetching (using TFilePrefetch) and if the gEnv and rootrc variable Cache.Directory is set, also enable the local caching of the prefetched blocks. if 'setPrefetching', the old prefetcher is enabled is the gEnv and rootrc variable is TFile.AsyncReading
Definition at line 771 of file TFileCacheRead.cxx.
TFileCacheRead implementation of SetEnablePrefetching.
This function is called from the constructor and should not be virtual.
Definition at line 781 of file TFileCacheRead.cxx.
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Set the file using this cache and reset the current blocks (if any).
Reimplemented in TTreeCache.
Definition at line 544 of file TFileCacheRead.cxx.
Definition at line 112 of file TFileCacheRead.h.
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Sort buffers to be prefetched in increasing order of positions.
Merge consecutive blocks if necessary.
Definition at line 571 of file TFileCacheRead.cxx.
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Definition at line 690 of file TFileCacheRead.cxx.
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Definition at line 36 of file TFileCacheRead.h.
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Definition at line 70 of file TFileCacheRead.h.
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Definition at line 71 of file TFileCacheRead.h.
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[fBNb]
Definition at line 69 of file TFileCacheRead.h.
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Definition at line 60 of file TFileCacheRead.h.
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Definition at line 58 of file TFileCacheRead.h.
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Definition at line 59 of file TFileCacheRead.h.
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[fBNb]
Definition at line 65 of file TFileCacheRead.h.
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[fBNseek]
Definition at line 62 of file TFileCacheRead.h.
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[fBNseek]
Definition at line 64 of file TFileCacheRead.h.
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[fBNseek]
Definition at line 66 of file TFileCacheRead.h.
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[fBNseek]
Definition at line 68 of file TFileCacheRead.h.
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Definition at line 61 of file TFileCacheRead.h.
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[fBNseek]
Definition at line 63 of file TFileCacheRead.h.
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[fBNseek]
Definition at line 67 of file TFileCacheRead.h.
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[fBufferSize] buffer of contiguous prefetched blocks
Definition at line 52 of file TFileCacheRead.h.
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Current buffer length (<= fBufferSize)
Definition at line 28 of file TFileCacheRead.h.
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Allocated size of fBuffer (at a given time)
Definition at line 27 of file TFileCacheRead.h.
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Original size of fBuffer.
Definition at line 26 of file TFileCacheRead.h.
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Number of bytes read for this cache.
Definition at line 30 of file TFileCacheRead.h.
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Number of extra bytes (overhead) read by the readahead buffer.
Definition at line 31 of file TFileCacheRead.h.
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reading by prefetching asynchronously
Definition at line 37 of file TFileCacheRead.h.
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Pointer to file.
Definition at line 51 of file TFileCacheRead.h.
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True if fSeek array is sorted.
Definition at line 53 of file TFileCacheRead.h.
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True when fBuffer contains something valid.
Definition at line 54 of file TFileCacheRead.h.
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[fNb] Length of long buffers
Definition at line 50 of file TFileCacheRead.h.
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Number of long buffers.
Definition at line 41 of file TFileCacheRead.h.
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Number of bytes read by basket to fill cached tree.
Definition at line 33 of file TFileCacheRead.h.
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Number of read calls by basket to fill cached tree.
Definition at line 34 of file TFileCacheRead.h.
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Number of blocks to be prefetched.
Definition at line 39 of file TFileCacheRead.h.
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Total size of prefetched blocks.
Definition at line 40 of file TFileCacheRead.h.
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[fNb] start of long buffers
Definition at line 46 of file TFileCacheRead.h.
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! Object that does the asynchronous reading in another thread
Definition at line 25 of file TFileCacheRead.h.
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Number of blocks prefetched.
Definition at line 55 of file TFileCacheRead.h.
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Number of read calls for this cache.
Definition at line 32 of file TFileCacheRead.h.
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[fNseek] Position on file of buffers to be prefetched
Definition at line 43 of file TFileCacheRead.h.
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[fNseek] sorted index table of fSeek
Definition at line 45 of file TFileCacheRead.h.
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[fNseek] Length of buffers to be prefetched
Definition at line 47 of file TFileCacheRead.h.
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[fNseek] Position of sorted blocks in fBuffer
Definition at line 49 of file TFileCacheRead.h.
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Allocated size of fSeek.
Definition at line 42 of file TFileCacheRead.h.
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[fNseek] Position on file of buffers to be prefetched (sorted)
Definition at line 44 of file TFileCacheRead.h.
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[fNseek] Length of buffers to be prefetched (sorted)
Definition at line 48 of file TFileCacheRead.h.