TDbiCache Class Reference

Concept Cache holding TDbiResultSet s for a specific database table. More...

#include <TDbiCache.hxx>

Collaboration diagram for TDbiCache:
Collaboration graph
[legend]

List of all members.

Public Types

typedef std::list
< TDbiResultSet * > 		ResultList_t

Public Member Functions

 TDbiCache (TDbiTableProxy &qp, const string &tableName)
virtual ~TDbiCache ()
UInt_t GetMaxSize () const
UInt_t GetCurSize () const
UInt_t GetNumAdopted () const
UInt_t GetNumReused () const
const TDbiResultSet * Search (const TVldContext &vc, const TDbi::Task &task) const
const TDbiResultSet * Search (const string &sqlQualifiers) const
const TDbiResultSet * Search (const TDbiValidityRec &vr, const string &sqlQualifiers="") const
 Secondary search.
ostream & ShowStatistics (ostream &msg) const
void Adopt (TDbiResultSet *res, bool generateKey=true)
void Purge ()
void SetStale ()

Private Member Functions

 TDbiCache (const TDbiCache &)
TDbiCache & operator= (const TDbiCache &)
const ResultList_t * GetSubCache (Int_t aggNo) const
void Purge (ResultList_t &subCache, const TDbiResultSet *res=0)

Private Attributes

TDbiTableProxy & fTableProxy
 TableProxy owning cache.
const string & fTableName
 Name of associated table.
std::map< Int_t, ResultList_t > fCache
UInt_t fCurSize
 Current size.
UInt_t fMaxSize
 Max (high water) size.
UInt_t fNumAdopted
 Total number adopted.
UInt_t fNumReused
 Number reused i.e. found.

Friends

class TDbiValidate

Detailed Description

Concept Cache holding TDbiResultSet s for a specific database table.

Purpose A TDbiCache is an object that minimises database I/O by caching query results. Queries are always first sent to the cache and only if not present are they sent down to the database. Contact: A.Finch@lancaster.ac.uk

Definition at line 37 of file TDbiCache.hxx.

Member Typedef Documentation

typedef std::list<TDbiResultSet*> TDbiCache::ResultList_t

Definition at line 45 of file TDbiCache.hxx.

Constructor & Destructor Documentation

TDbiCache::TDbiCache ( TDbiTableProxy &  qp,
const string &  tableName 
) 
   
     Purpose:  Constructor
   
     Arguments:
                in  qp         Owning TDbiTableProxy.
                in  tableName  Name of associated table
   
     Return:    n/a
   
     Contact:   N. West
   
     Specification:-
     =============
   
     o Create empty cache.
   
   
     Program Notes:-
     =============
   
     None.

Definition at line 61 of file TDbiCache.cxx.

References SK_DBI_Trace.

00061                                                                :
00062 fTableProxy(qp),
00063 fTableName(tableName),
00064 fCurSize(0),
00065 fMaxSize(0),
00066 fNumAdopted(0),
00067 fNumReused(0)
00068 {
00069 
00070 
00071   SK_DBI_Trace( "Creating TDbiCache" << "  ");
00072 
00073 }

TDbiCache::~TDbiCache (  )  [virtual] 
   
     Purpose: Destructor
   
     Arguments:
       None.
   
     Return:    n/a
   
     Contact:   N. West
   
     Specification:-
     =============
   
     o  Destroy cache and all owned TDbiResultSets.
   
   
     Program Notes:-
     =============
   
     None.

Definition at line 98 of file TDbiCache.cxx.

References fCache, GetSubCache(), Purge(), and SK_DBI_Trace.

00098                       {
00099 
00100 
00101 
00102   SK_DBI_Trace( "Destroying TDbiCache" << "  ");
00103 
00104   // Purge the AggNo == -1 cache before deleting.  For extended
00105   // context queries it can have TDbiResultSetAggs that are clients of
00106   // TDbiResultSetNonAggs in the same cache, so purging will remove clientless
00107   // TDbiResultSetAggs which should in turn make their TDbiResultSetNonAggs
00108   // clientless.
00109   if ( this->GetSubCache(-1) ) this->Purge(fCache[-1]);
00110 
00111   for ( CacheItr_t itr = fCache.begin(); itr != fCache.end(); ++itr) {
00112     ResultList_t& subCache = itr->second;
00113     for ( SubCacheItr_t sitr = subCache.begin();
00114           sitr != subCache.end();
00115           ++sitr) delete *sitr;
00116   }
00117 
00118 }

Here is the call graph for this function:

TDbiCache::TDbiCache ( const TDbiCache &   )  [private]

Member Function Documentation

void TDbiCache::Adopt ( TDbiResultSet *  res,
bool  generateKey = true 
) 
   
     Purpose:  Adopt and own a TDbiResultSet
   
     Arguments:
       res          in    The TDbiResiult to be adopted.
       generateKey  in    If true generate key
   
     Return:  None.
   
     Contact:   N. West
   
     Specification:-
     =============
   
     o Create new sub-cache for aggregate if necessary.
   
     o Purge sub-cache of unwanted data and adopt new result.
   
     Program Notes:-
     =============
   
     New entries are added to the end of the sub-cache unwanted entries
     are always removed from the beginning so sub-cache is a FIFO.

Definition at line 146 of file TDbiCache.cxx.

References fCache, fCurSize, fMaxSize, fNumAdopted, TDbiResultSet::GenerateKey(), TDbiValidityRec::GetAggregateNo(), TDbiResultSet::GetKey(), GetSubCache(), TDbiResultSet::GetValidityRec(), TDbiResultSet::GetValidityRecGlobal(), Purge(), SK_DBI_Debug, SK_DBI_Info, and TDbiResultSet::TableName().

Referenced by TDbiTableProxy::Query(), and TDbiTableProxy::RestoreFromL2Cache().

00146                                                          {
00147 
00148   if ( ! res ) return;
00149   int aggNo = res->GetValidityRec().GetAggregateNo();
00150 
00151 //  Prime sub-cache if necessary.
00152   if ( ! this->GetSubCache(aggNo) ) {
00153     ResultList_t emptyList;
00154     fCache[aggNo] = emptyList;
00155   }
00156 
00157 //  Purge expired entries and add new result to cache.
00158   ResultList_t& subCache = fCache[aggNo];
00159   Purge(subCache, res);
00160   subCache.push_back(res);
00161   ++fCurSize;
00162   ++fNumAdopted;
00163   SK_DBI_Debug( "Adopting result for " << res->TableName()
00164                          << "  " <<   res->GetValidityRecGlobal()
00165                          << "\nCache size now " << fCurSize << "  ");
00166   if ( fCurSize > fMaxSize ) fMaxSize = fCurSize;
00167   // If required generate key.
00168   if ( generateKey ) {
00169     res->GenerateKey();
00170     SK_DBI_Info( "Caching new results: ResultKey: " <<  *res->GetKey());
00171   }
00172 }

Here is the call graph for this function:

Here is the caller graph for this function:

UInt_t TDbiCache::GetCurSize (  )  const [inline]

Definition at line 56 of file TDbiCache.hxx.

References fCurSize.

00056 { return fCurSize; }

UInt_t TDbiCache::GetMaxSize (  )  const [inline]

Definition at line 55 of file TDbiCache.hxx.

References fMaxSize.

00055 { return fMaxSize; }

UInt_t TDbiCache::GetNumAdopted (  )  const [inline]

Definition at line 57 of file TDbiCache.hxx.

References fNumAdopted.

00057 { return fNumAdopted; }

UInt_t TDbiCache::GetNumReused (  )  const [inline]

Definition at line 58 of file TDbiCache.hxx.

References fNumReused.

00058 { return fNumReused; }

const ResultList_t * TDbiCache::GetSubCache ( Int_t  aggNo  )  const [private] 
   
     Purpose:  Return sub-cache for aggregate or 0 if none..

Definition at line 179 of file TDbiCache.cxx.

References ConstCacheItr_t, and fCache.

Referenced by Adopt(), Search(), and ~TDbiCache().

00179                                                             {
00180 
00181   ConstCacheItr_t itr = fCache.find(aggNo);
00182   return ( itr == fCache.end() ) ? 0 : &itr->second;
00183 
00184 }

Here is the caller graph for this function:

TDbiCache& TDbiCache::operator= ( const TDbiCache &   )  [private]
void TDbiCache::Purge ( ResultList_t &  subCache,
const TDbiResultSet *  res = 0 
) [private] 
   
     Purpose: Purge surplus sub-cache memebers.
   
     Arguments:
       subCache   in/out  The sub-cache to be purged
       res        in      Optional TDbiResultSet (default =0)
   
     Return:   None.
   
     Contact:   N. West
   
     Specification:-
     =============
   
     o Purge surplus sub-cache members i.e. those without clients.
   
     o If a TDbiResultSet is supplied, only purge entries that have
       expired relative to it or are stale.
   
     Program Notes:-
     =============

Definition at line 242 of file TDbiCache.cxx.

References TDbiResultSet::CanDelete(), fCurSize, TDbiResultSet::GetNumClients(), TDbiResultSet::GetValidityRec(), SK_DBI_Debug, and TDbiResultSet::TableName().

00242                                                                       {
00243 
00244 
00245 //  Passing a TDbiResultSet allows the sub-cache to hold entries
00246 //  for different detector types, simulation masks and tasks.
00247 
00248     for ( SubCacheItr_t itr = subCache.begin(); itr != subCache.end(); ) {
00249     TDbiResultSet* pRes = *itr;
00250 
00251      if (      pRes->GetNumClients() == 0
00252           && (    ! res
00253                || pRes->CanDelete(res)  ) ) {
00254 
00255       SK_DBI_Debug( "Purging " << pRes->GetValidityRec()
00256                              << " from " << pRes->TableName()
00257                              << " cache. Cache size now "
00258                              << fCurSize-1 << "  ");
00259       delete pRes;
00260 //    Erasing increments iterator.
00261       itr = subCache.erase(itr);
00262       --fCurSize;
00263 
00264     }
00265     else {
00266       ++itr;
00267     }
00268   }
00269 
00270 }

Here is the call graph for this function:

void TDbiCache::Purge (  )  
   
     Purpose: Purge all sub-caches.
   
     Arguments:  None.
   
    Return:   None.
   
     Contact:   N. West
   
     Specification:-
     =============
   
     o Purge all sub_caches.
   
     Program Notes:-
     =============
   
     The first sub-cached to be purged must be sub-cache -1 as
     its members may be aggregated and consequently will be
     connected to members in other caches.

Definition at line 209 of file TDbiCache.cxx.

References fCache.

Referenced by Adopt(), TDbiDatabaseManager::PurgeCaches(), and ~TDbiCache().

00209                       {
00210 
00211 
00212 
00213 
00214   for ( CacheItr_t itr = fCache.begin(); itr != fCache.end(); ++itr
00215       ) Purge(itr->second);
00216 
00217 }

Here is the caller graph for this function:

const TDbiResultSet * TDbiCache::Search ( const TDbiValidityRec &  vrec,
const string &  sqlQualifiers = "" 
) const

Secondary search. 

   
     Purpose:  Search sub-cache for TDbiResultSet set matching a TDbiValidityRec.
               with an optional sqlQualifiers string.
     Return:   Pointer to matching TDbiResultSet, or = 0 if none.

Definition at line 278 of file TDbiCache.cxx.

References fNumReused, fTableName, TDbiValidityRec::GetAggregateNo(), TDbiResultSet::GetNumAggregates(), TDbiResultSet::GetNumRows(), GetSubCache(), TDbiResultSet::Satisfies(), and SK_DBI_Trace.

00279                                                                      {
00280 
00281 
00282   Int_t aggNo = vrec.GetAggregateNo();
00283 
00284   SK_DBI_Trace( "Secondary cache search of table " << fTableName
00285                          << " for  " << vrec
00286                             << (sqlQualifiers != "" ? sqlQualifiers : "" ) << "  ");
00287   const ResultList_t* subCache = this->GetSubCache(aggNo);
00288   if ( ! subCache ) {
00289     SK_DBI_Trace( "Secondary cache search failed." << "  ");
00290     return 0;
00291   }
00292 
00293   ConstSubCacheItr_t itrEnd = subCache->end();
00294   for ( ConstSubCacheItr_t itr = subCache->begin();
00295         itr != itrEnd;
00296         ++itr) {
00297     TDbiResultSet* res = *itr;
00298     if ( res->Satisfies(vrec,sqlQualifiers) ) {
00299       fNumReused += res->GetNumAggregates();
00300       SK_DBI_Trace( "Secondary cache search succeeded.  Result set no. of rows: "
00301                                 << res->GetNumRows() << "  ");
00302       return res;
00303     }
00304   }
00305 
00306   SK_DBI_Trace( "Secondary cache search failed." << "  ");
00307   return 0;
00308 }

Here is the call graph for this function:

const TDbiResultSet * TDbiCache::Search ( const string &  sqlQualifiers  )  const 
   
     Purpose:  Search primary cache for TDbiResultSet set matching a new query.
   
     Arguments:
       sqlQualifiers  in  The SQL qualifiers (context-sql;data-sql;fill-options)
   
     Return:   Pointer to matching TDbiResultSet, or = 0 if none.

Definition at line 379 of file TDbiCache.cxx.

References fNumReused, fTableName, TDbiResultSet::GetNumAggregates(), TDbiResultSet::GetNumRows(), GetSubCache(), TDbiResultSet::Satisfies(), and SK_DBI_Trace.

00379                                                                         {
00380 
00381   SK_DBI_Trace( "Primary cache search of table " << fTableName
00382                          << " for  SQL " << sqlQualifiers << "  ");
00383   const ResultList_t* subCache = this->GetSubCache(-1);
00384   if ( ! subCache ) {
00385     SK_DBI_Trace( "Primary cache search failed" << "  ");
00386     return 0;
00387   }
00388   for ( ConstSubCacheItr_t itr = subCache->begin();
00389         itr != subCache->end();
00390         ++itr) {
00391     TDbiResultSet* res = *itr;
00392     if ( res->Satisfies(sqlQualifiers) ) {
00393       fNumReused += res->GetNumAggregates();
00394       SK_DBI_Trace( "Primary cache search succeeded Result set no. of rows: "
00395                                 << res->GetNumRows() << "  ");
00396       return res;
00397     }
00398   }
00399   SK_DBI_Trace( "Primary cache search failed" << "  ");
00400   return 0;
00401 }

Here is the call graph for this function:

const TDbiResultSet * TDbiCache::Search ( const TVldContext &  vc,
const TDbi::Task &  task 
) const 
   
     Purpose:  Search primary cache for TDbiResultSet set matching a new query.
   
     Arguments:
       vc           in    Context of new query
       task         in    Task of new query
   
     Return:   Pointer to matching TDbiResultSet, or = 0 if none.

Definition at line 321 of file TDbiCache.cxx.

References DbiSimFlag::AsString(), fNumReused, fTableName, TDbiSimFlagAssociation::Get(), TVldContext::GetDetector(), TDbiResultSet::GetNumAggregates(), TDbiResultSet::GetNumRows(), TVldContext::GetSimFlag(), GetSubCache(), TVldContext::GetTimeStamp(), TDbiSimFlagAssociation::Instance(), TDbiResultSet::Satisfies(), SK_DBI_Debug, and SK_DBI_Trace.

Referenced by TDbiTableProxy::Query(), and TDbiTableProxy::RestoreFromL2Cache().

00322                                                                {
00323 
00324   SK_DBI_Trace( "Primary cache search of table " << fTableName
00325                          << " for  " << vc
00326                          << " with task " << task << "  ");
00327   const ResultList_t* subCache = this->GetSubCache(-1);
00328   if ( ! subCache ) {
00329     SK_DBI_Trace( "Primary cache search failed - sub-cache -1 is empty" << "  ");
00330     return 0;
00331   }
00332 
00333   // Loop over all possible SimFlag associations.
00334 
00335   DbiDetector::Detector_t     det(vc.GetDetector());
00336   DbiSimFlag::SimFlag_t       sim(vc.GetSimFlag());
00337   TVldTimeStamp              ts(vc.GetTimeStamp());
00338 
00339   TDbiSimFlagAssociation::SimList_t simList
00340                   = TDbiSimFlagAssociation::Instance().Get(sim);
00341 
00342   TDbiSimFlagAssociation::SimList_t::iterator listItr    = simList.begin();
00343   TDbiSimFlagAssociation::SimList_t::iterator listItrEnd = simList.end();
00344   while ( listItr !=  listItrEnd ) {
00345 
00346     DbiSimFlag::SimFlag_t simTry = *listItr;
00347     TVldContext vcTry(det,simTry,ts);
00348 
00349     SK_DBI_Debug( "  Searching cache with SimFlag: "
00350                            << DbiSimFlag::AsString(simTry) << "  ");
00351     for ( ConstSubCacheItr_t itr = subCache->begin();
00352           itr != subCache->end();
00353           ++itr) {
00354       TDbiResultSet* res = *itr;
00355       if ( res->Satisfies(vcTry,task) ) {
00356         fNumReused += res->GetNumAggregates();
00357         SK_DBI_Trace( "Primary cache search succeeded. Result set no. of rows: "
00358                                   << res->GetNumRows() << "  ");
00359         return res;
00360       }
00361     }
00362 
00363   SK_DBI_Trace( "Primary cache search failed." << "  ");
00364   ++listItr;
00365   }
00366 
00367   return 0;
00368 }

Here is the call graph for this function:

Here is the caller graph for this function:

void TDbiCache::SetStale (  )  
   
     Purpose: Set all entries in the cache as stale i.e. don't reuse.
   
     Arguments: None
   
     Return:    n/a
   
     Contact:   N. West
   
     Specification:-
     =============
   
     o Set all entries in the cache as stale i.e. don't reuse.
   
     Program Notes:-
     =============
   
     This member function can be used to effectively clear the cache.
     As existing TDbiResultSet objects currently in the cache may currently
     have clients, its not possible simply to delete them, so instead
     this function marks them as stale so they will not be reused and
     will eventually be dropped once all their clients have disconnected.

Definition at line 429 of file TDbiCache.cxx.

References fCache.

00429                          {
00430 
00431   for ( CacheItr_t cacheItr = fCache.begin();
00432         cacheItr != fCache.end();
00433         ++cacheItr
00434         ) {
00435     ResultList_t& subcache = cacheItr->second;
00436 
00437     for ( SubCacheItr_t subcacheItr = subcache.begin();
00438           subcacheItr != subcache.end();
00439           ++subcacheItr ) (*subcacheItr)->SetCanReuse(kFALSE);
00440   }
00441 
00442 }

ostream & TDbiCache::ShowStatistics ( ostream &  msg  )  const 
   
     Purpose: Display statistics for cache on supplied ostream.
   
     Arguments:
       msg          in    ostream to output on.
   
     Return: Updated ostream.
   
     Contact:   N. West
   
     Specification:-
     =============
   
     o Output : Current Size, Max size, Adopted and Resused as
                4 10 character wide fields.
   
     Program Notes:-
     =============
   
     None.

Definition at line 467 of file TDbiCache.cxx.

References fCurSize, fMaxSize, fNumAdopted, and fNumReused.

00467                                                      {
00468 
00469   MsgFormat ifmt("%10i");
00470 
00471   msg << ifmt(fCurSize) << ifmt(fMaxSize)
00472       << ifmt(fNumAdopted) << ifmt(fNumReused);
00473   return msg;
00474 
00475 }

Friends And Related Function Documentation

friend class TDbiValidate [friend]

Definition at line 40 of file TDbiCache.hxx.

Member Data Documentation

std::map<Int_t,ResultList_t> TDbiCache::fCache [private]

Map of sub-caches indexed by aggregate number. Each sub-cache is a list of owned results for that aggregate.

Definition at line 101 of file TDbiCache.hxx.

Referenced by Adopt(), GetSubCache(), Purge(), SetStale(), and ~TDbiCache().

UInt_t TDbiCache::fCurSize [mutable, private]

Current size.

Definition at line 104 of file TDbiCache.hxx.

Referenced by Adopt(), GetCurSize(), Purge(), and ShowStatistics().

UInt_t TDbiCache::fMaxSize [mutable, private]

Max (high water) size.

Definition at line 107 of file TDbiCache.hxx.

Referenced by Adopt(), GetMaxSize(), and ShowStatistics().

UInt_t TDbiCache::fNumAdopted [mutable, private]

Total number adopted.

Definition at line 110 of file TDbiCache.hxx.

Referenced by Adopt(), GetNumAdopted(), and ShowStatistics().

UInt_t TDbiCache::fNumReused [mutable, private]

Number reused i.e. found.

Definition at line 113 of file TDbiCache.hxx.

Referenced by GetNumReused(), Search(), and ShowStatistics().

const string& TDbiCache::fTableName [private]

Name of associated table.

Definition at line 96 of file TDbiCache.hxx.

Referenced by Search().

TDbiTableProxy& TDbiCache::fTableProxy [private]

TableProxy owning cache.

Definition at line 93 of file TDbiCache.hxx.

The documentation for this class was generated from the following files:
Generated on 11 Aug 2013 for SKDatabase by  doxygen 1.6.1