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;
}
/* 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;
}
}
void NamespaceDetails::advanceCapExtent( const char *ns ) {
// We want cappedLastDelRecLastExtent() to be the last DeletedRecord of the prev cap extent
// (or DiskLoc() if new capExtent == firstExtent)
if ( capExtent == lastExtent )
getDur().writingDiskLoc( cappedLastDelRecLastExtent() ) = DiskLoc();
else {
DiskLoc i = cappedFirstDeletedInCurExtent();
for (; !i.isNull() && nextIsInCapExtent( i ); i = i.drec()->nextDeleted );
getDur().writingDiskLoc( cappedLastDelRecLastExtent() ) = i;
}
getDur().writingDiskLoc( capExtent ) = theCapExtent()->xnext.isNull() ? firstExtent : theCapExtent()->xnext;
/* this isn't true if a collection has been renamed...that is ok just used for diagnostics */
//dassert( theCapExtent()->ns == ns );
theCapExtent()->assertOk();
getDur().writingDiskLoc( capFirstNewRecord ) = DiskLoc();
}
