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/**
* Copyright (C) 2008 10gen Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/* clientcursor.cpp
ClientCursor is a wrapper that represents a cursorid from our database
application's perspective.
Cursor -- and its derived classes -- are our internal cursors.
*/
#include "stdafx.h"
#include "query.h"
#include "introspect.h"
#include <time.h>
#include "db.h"
#include "commands.h"
namespace mongo {
CCById clientCursorsById;
/* ------------------------------------------- */
long long IdSet_Deprecated::size_ = 0;
long long IdSet_Deprecated::maxSize_ = 200 * 1024 * 1024;
typedef multimap<DiskLoc, ClientCursor*> ByLoc;
ByLoc byLoc;
unsigned byLocSize() {
return byLoc.size();
}
void ClientCursor::setLastLoc(DiskLoc L) {
if ( L == _lastLoc )
return;
if ( !_lastLoc.isNull() ) {
ByLoc::iterator i = kv_find(byLoc, _lastLoc, this);
if ( i != byLoc.end() )
byLoc.erase(i);
}
if ( !L.isNull() )
byLoc.insert( make_pair(L, this) );
_lastLoc = L;
}
/* ------------------------------------------- */
/* must call this when a btree node is updated */
//void removedKey(const DiskLoc& btreeLoc, int keyPos) {
//}
/* todo: this implementation is incomplete. we use it as a prefix for dropDatabase, which
works fine as the prefix will end with '.'. however, when used with drop and
deleteIndexes, this could take out cursors that belong to something else -- if you
drop "foo", currently, this will kill cursors for "foobar".
*/
void ClientCursor::invalidate(const char *nsPrefix) {
vector<ClientCursor*> toDelete;
int len = strlen(nsPrefix);
assert( len > 0 && strchr(nsPrefix, '.') );
for ( ByLoc::iterator i = byLoc.begin(); i != byLoc.end(); ++i ) {
ClientCursor *cc = i->second;
if ( strncmp(nsPrefix, cc->ns.c_str(), len) == 0 )
toDelete.push_back(i->second);
}
for ( vector<ClientCursor*>::iterator i = toDelete.begin(); i != toDelete.end(); ++i )
delete (*i);
}
/* called every 4 seconds. millis is amount of idle time passed since the last call -- could be zero */
void idleTimeReport(unsigned millis) {
assert( dbMutexInfo.isLocked() );
for ( ByLoc::iterator i = byLoc.begin(); i != byLoc.end(); ) {
ByLoc::iterator j = i;
i++;
if( (j->second->idleAgeMillis += millis) > 600000 ) {
log(2) << "killing old cursor " << j->second->cursorid << ' ' << j->second->ns << " idle:" << j->second->idleAgeMillis << "ms\n";
delete j->second;
}
}
}
/* must call when a btree bucket going away.
note this is potentially slow
*/
void aboutToDeleteBucket(const DiskLoc& b) {
RARELY if ( byLoc.size() > 70 ) {
log() << "perf warning: byLoc.size=" << byLoc.size() << " in aboutToDeleteBucket\n";
}
for ( ByLoc::iterator i = byLoc.begin(); i != byLoc.end(); i++ )
i->second->c->aboutToDeleteBucket(b);
}
/* must call this on a delete so we clean up the cursors. */
void aboutToDelete(const DiskLoc& dl) {
ByLoc::iterator j = byLoc.lower_bound(dl);
ByLoc::iterator stop = byLoc.upper_bound(dl);
if ( j == stop )
return;
assert( dbMutexInfo.isLocked() );
vector<ClientCursor*> toAdvance;
while ( 1 ) {
toAdvance.push_back(j->second);
WIN assert( j->first == dl );
++j;
if ( j == stop )
break;
}
wassert( toAdvance.size() < 5000 );
for ( vector<ClientCursor*>::iterator i = toAdvance.begin();
i != toAdvance.end(); ++i )
{
Cursor *c = (*i)->c.get();
c->checkLocation();
DiskLoc tmp1 = c->refLoc();
if ( tmp1 != dl ) {
/* this might indicate a failure to call ClientCursor::updateLocation() */
problem() << "warning: cursor loc " << tmp1 << " does not match byLoc position " << dl << " !" << endl;
}
c->advance();
if ( c->eof() ) {
// advanced to end -- delete cursor
delete *i;
}
else {
wassert( c->refLoc() != dl );
(*i)->updateLocation();
}
}
}
ClientCursor::~ClientCursor() {
assert( pos != -2 );
setLastLoc( DiskLoc() ); // removes us from bylocation multimap
clientCursorsById.erase(cursorid);
// defensive:
(CursorId&) cursorid = -1;
pos = -2;
}
/* call when cursor's location changes so that we can update the
cursorsbylocation map. if you are locked and internally iterating, only
need to call when you are ready to "unlock".
*/
void ClientCursor::updateLocation() {
assert( cursorid );
idleAgeMillis = 0;
DiskLoc cl = c->refLoc();
if ( lastLoc() == cl ) {
//log() << "info: lastloc==curloc " << ns << '\n';
return;
}
setLastLoc(cl);
c->noteLocation();
}
int ctmLast = 0; // so we don't have to do find() which is a little slow very often.
long long ClientCursor::allocCursorId() {
long long x;
int ctm = (int) curTimeMillis();
while ( 1 ) {
x = (((long long)rand()) << 32);
x = x | ctm | 0x80000000; // OR to make sure not zero
if ( ctm != ctmLast || ClientCursor::find(x, false) == 0 )
break;
}
ctmLast = ctm;
DEV out() << " alloccursorid " << x << endl;
return x;
}
// QUESTION: Restrict to the namespace from which this command was issued?
// Alternatively, make this command admin-only?
class CmdCursorInfo : public Command {
public:
CmdCursorInfo() : Command( "cursorInfo" ) {}
virtual bool slaveOk() { return true; }
virtual void help( stringstream& help ) const {
help << " example: { cursorInfo : 1 }";
}
bool run(const char *dbname, BSONObj& jsobj, string& errmsg, BSONObjBuilder& result, bool fromRepl ){
result.append("byLocation_size", unsigned( byLoc.size() ) );
result.append("clientCursors_size", unsigned( clientCursorsById.size() ) );
return true;
}
} cmdCursorInfo;
} // namespace mongo
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