void NamespaceDetails::cappedTruncateLastDelUpdate() {
if ( _capExtent == _firstExtent ) {
// Only one extent of the collection is in use, so there
// is no deleted record in a previous extent, so nullify
// cappedLastDelRecLastExtent().
cappedLastDelRecLastExtent().writing() = DiskLoc();
}
else {
// Scan through all deleted records in the collection
// until the last deleted record for the extent prior
// to the new capExtent is found. Then set
// cappedLastDelRecLastExtent() to that deleted record.
DiskLoc i = cappedListOfAllDeletedRecords();
for( ;
!i.drec()->nextDeleted().isNull() &&
!inCapExtent( i.drec()->nextDeleted() );
i = i.drec()->nextDeleted() );
// In our capped storage model, every extent must have at least one
// deleted record. Here we check that 'i' is not the last deleted
// record. (We expect that there will be deleted records in the new
// capExtent as well.)
verify( !i.drec()->nextDeleted().isNull() );
cappedLastDelRecLastExtent().writing() = i;
}
}
DiskLoc NamespaceDetails::__capAlloc( int len ) {
DiskLoc prev = cappedLastDelRecLastExtent();
DiskLoc i = cappedFirstDeletedInCurExtent();
DiskLoc ret;
for (; !i.isNull() && inCapExtent( i ); prev = i, i = i.drec()->nextDeleted() ) {
// We need to keep at least one DR per extent in cappedListOfAllDeletedRecords(),
// so make sure there's space to create a DR at the end.
if ( i.drec()->lengthWithHeaders() >= len + 24 ) {
ret = i;
break;
}
}
/* unlink ourself from the deleted list */
if ( !ret.isNull() ) {
if ( prev.isNull() )
cappedListOfAllDeletedRecords().writing() = ret.drec()->nextDeleted();
else
prev.drec()->nextDeleted().writing() = ret.drec()->nextDeleted();
ret.drec()->nextDeleted().writing().setInvalid(); // defensive.
verify( ret.drec()->extentOfs() < ret.getOfs() );
}
return ret;
}
bool NamespaceDetails::nextIsInCapExtent( const DiskLoc &dl ) const {
verify( !dl.isNull() );
DiskLoc next = dl.drec()->nextDeleted();
if ( next.isNull() )
return false;
return inCapExtent( next );
}
/* combine adjacent deleted records *for the current extent* of the capped collection
this is O(n^2) but we call it for capped tables where typically n==1 or 2!
(or 3...there will be a little unused sliver at the end of the extent.)
*/
void NamespaceDetails::compact() {
DDD( "NamespaceDetails::compact enter" );
verify( isCapped() );
vector<DiskLoc> drecs;
// Pull out capExtent's DRs from deletedList
DiskLoc i = cappedFirstDeletedInCurExtent();
for (; !i.isNull() && inCapExtent( i ); i = i.drec()->nextDeleted() ) {
DDD( "\t" << i );
drecs.push_back( i );
}
getDur().writingDiskLoc( cappedFirstDeletedInCurExtent() ) = i;
std::sort( drecs.begin(), drecs.end() );
DDD( "\t drecs.size(): " << drecs.size() );
vector<DiskLoc>::const_iterator j = drecs.begin();
verify( j != drecs.end() );
DiskLoc a = *j;
while ( 1 ) {
j++;
if ( j == drecs.end() ) {
DDD( "\t compact adddelrec" );
addDeletedRec(a.drec(), a);
break;
}
DiskLoc b = *j;
while ( a.a() == b.a() && a.getOfs() + a.drec()->lengthWithHeaders() == b.getOfs() ) {
// a & b are adjacent. merge.
getDur().writingInt( a.drec()->lengthWithHeaders() ) += b.drec()->lengthWithHeaders();
j++;
if ( j == drecs.end() ) {
DDD( "\t compact adddelrec2" );
addDeletedRec(a.drec(), a);
return;
}
b = *j;
}
DDD( "\t compact adddelrec3" );
addDeletedRec(a.drec(), a);
a = b;
}
}
/* combine adjacent deleted records *for the current extent* of the capped collection
this is O(n^2) but we call it for capped tables where typically n==1 or 2!
(or 3...there will be a little unused sliver at the end of the extent.)
*/
void NamespaceDetails::compact() {
assert(capped);
list<DiskLoc> drecs;
// Pull out capExtent's DRs from deletedList
DiskLoc i = cappedFirstDeletedInCurExtent();
for (; !i.isNull() && inCapExtent( i ); i = i.drec()->nextDeleted )
drecs.push_back( i );
getDur().writingDiskLoc( cappedFirstDeletedInCurExtent() ) = i;
// This is the O(n^2) part.
drecs.sort();
list<DiskLoc>::iterator j = drecs.begin();
assert( j != drecs.end() );
DiskLoc a = *j;
while ( 1 ) {
j++;
if ( j == drecs.end() ) {
DEBUGGING out() << "TEMP: compact adddelrec\n";
addDeletedRec(a.drec(), a);
break;
}
DiskLoc b = *j;
while ( a.a() == b.a() && a.getOfs() + a.drec()->lengthWithHeaders == b.getOfs() ) {
// a & b are adjacent. merge.
getDur().writingInt( a.drec()->lengthWithHeaders ) += b.drec()->lengthWithHeaders;
j++;
if ( j == drecs.end() ) {
DEBUGGING out() << "temp: compact adddelrec2\n";
addDeletedRec(a.drec(), a);
return;
}
b = *j;
}
DEBUGGING out() << "temp: compact adddelrec3\n";
addDeletedRec(a.drec(), a);
a = b;
}
}
/* everything from end on, eliminate from the capped collection.
@param inclusive if true, deletes end (i.e. closed or open range)
*/
void NamespaceDetails::cappedTruncateAfter(const char *ns, DiskLoc end, bool inclusive) {
DEV assert( this == nsdetails(ns) );
assert( cappedLastDelRecLastExtent().isValid() );
bool foundLast = false;
while( 1 ) {
if ( foundLast ) {
break;
}
DiskLoc curr = theCapExtent()->lastRecord;
assert( !curr.isNull() );
if ( curr == end ) {
if ( inclusive ) {
foundLast = true;
} else {
break;
}
}
uassert( 13415, "emptying the collection is not allowed", stats.nrecords > 1 );
if ( !capLooped() ) {
theDataFileMgr.deleteRecord(ns, curr.rec(), curr, true);
compact();
if ( theCapExtent()->lastRecord.isNull() ) {
assert( !theCapExtent()->xprev.isNull() );
capExtent = theCapExtent()->xprev;
theCapExtent()->assertOk();
if ( capExtent == firstExtent ) {
cappedLastDelRecLastExtent() = DiskLoc();
} else {
// slow - there's no prev ptr for deleted rec
DiskLoc i = cappedListOfAllDeletedRecords();
for( ;
!i.drec()->nextDeleted.isNull() &&
!inCapExtent( i.drec()->nextDeleted );
i = i.drec()->nextDeleted );
assert( !i.drec()->nextDeleted.isNull() ); // I believe there is always at least one drec per extent
cappedLastDelRecLastExtent() = i;
}
}
continue;
}
theDataFileMgr.deleteRecord(ns, curr.rec(), curr, true);
compact();
if ( curr == capFirstNewRecord ) { // invalid, but can compare locations
capExtent = ( capExtent == firstExtent ) ? lastExtent : theCapExtent()->xprev;
theCapExtent()->assertOk();
assert( !theCapExtent()->firstRecord.isNull() );
capFirstNewRecord = theCapExtent()->firstRecord;
if ( capExtent == firstExtent ) {
cappedLastDelRecLastExtent() = DiskLoc();
} else {
// slow - there's no prev ptr for deleted rec
DiskLoc i = cappedListOfAllDeletedRecords();
for( ;
!i.drec()->nextDeleted.isNull() &&
!inCapExtent( i.drec()->nextDeleted );
i = i.drec()->nextDeleted );
assert( !i.drec()->nextDeleted.isNull() ); // I believe there is always at least one drec per extent
cappedLastDelRecLastExtent() = i;
}
}
}
}
