bool mergeChunks( OperationContext* txn,
const NamespaceString& nss,
const BSONObj& minKey,
const BSONObj& maxKey,
const OID& epoch,
string* errMsg ) {
//
// Get sharding state up-to-date
//
ConnectionString configLoc = ConnectionString::parse( shardingState.getConfigServer(),
*errMsg );
if ( !configLoc.isValid() ){
warning() << *errMsg << endl;
return false;
}
//
// Get the distributed lock
//
ScopedDistributedLock collLock( configLoc, nss.ns() );
collLock.setLockMessage( stream() << "merging chunks in " << nss.ns() << " from "
<< minKey << " to " << maxKey );
Status acquisitionStatus = collLock.tryAcquire();
if (!acquisitionStatus.isOK()) {
*errMsg = stream() << "could not acquire collection lock for " << nss.ns()
<< " to merge chunks in [" << minKey << "," << maxKey << ")"
<< causedBy(acquisitionStatus);
warning() << *errMsg << endl;
return false;
}
//
// We now have the collection lock, refresh metadata to latest version and sanity check
//
ChunkVersion shardVersion;
Status status = shardingState.refreshMetadataNow(txn, nss.ns(), &shardVersion);
if ( !status.isOK() ) {
*errMsg = str::stream() << "could not merge chunks, failed to refresh metadata for "
<< nss.ns() << causedBy( status.reason() );
warning() << *errMsg << endl;
return false;
}
if ( epoch.isSet() && shardVersion.epoch() != epoch ) {
*errMsg = stream() << "could not merge chunks, collection " << nss.ns()
<< " has changed" << " since merge was sent" << "(sent epoch : "
<< epoch.toString()
<< ", current epoch : " << shardVersion.epoch().toString() << ")";
warning() << *errMsg << endl;
return false;
}
CollectionMetadataPtr metadata = shardingState.getCollectionMetadata( nss.ns() );
if ( !metadata || metadata->getKeyPattern().isEmpty() ) {
*errMsg = stream() << "could not merge chunks, collection " << nss.ns()
<< " is not sharded";
warning() << *errMsg << endl;
return false;
}
dassert( metadata->getShardVersion().equals( shardVersion ) );
if ( !metadata->isValidKey( minKey ) || !metadata->isValidKey( maxKey ) ) {
*errMsg = stream() << "could not merge chunks, the range "
<< rangeToString( minKey, maxKey ) << " is not valid"
<< " for collection " << nss.ns() << " with key pattern "
<< metadata->getKeyPattern();
warning() << *errMsg << endl;
return false;
}
//
// Get merged chunk information
//
ChunkVersion mergeVersion = metadata->getCollVersion();
mergeVersion.incMinor();
OwnedPointerVector<ChunkType> chunksToMerge;
ChunkType itChunk;
itChunk.setMin( minKey );
itChunk.setMax( minKey );
itChunk.setNS( nss.ns() );
itChunk.setShard( shardingState.getShardName() );
while ( itChunk.getMax().woCompare( maxKey ) < 0 &&
metadata->getNextChunk( itChunk.getMax(), &itChunk ) ) {
auto_ptr<ChunkType> saved( new ChunkType );
itChunk.cloneTo( saved.get() );
chunksToMerge.mutableVector().push_back( saved.release() );
}
if ( chunksToMerge.empty() ) {
*errMsg = stream() << "could not merge chunks, collection " << nss.ns()
<< " range starting at " << minKey
<< " and ending at " << maxKey
<< " does not belong to shard " << shardingState.getShardName();
warning() << *errMsg << endl;
return false;
}
//
// Validate the range starts and ends at chunks and has no holes, error if not valid
//
BSONObj firstDocMin = ( *chunksToMerge.begin() )->getMin();
BSONObj firstDocMax = ( *chunksToMerge.begin() )->getMax();
// minKey is inclusive
bool minKeyInRange = rangeContains( firstDocMin, firstDocMax, minKey );
if ( !minKeyInRange ) {
*errMsg = stream() << "could not merge chunks, collection " << nss.ns()
<< " range starting at " << minKey
<< " does not belong to shard " << shardingState.getShardName();
warning() << *errMsg << endl;
return false;
}
BSONObj lastDocMin = ( *chunksToMerge.rbegin() )->getMin();
BSONObj lastDocMax = ( *chunksToMerge.rbegin() )->getMax();
// maxKey is exclusive
bool maxKeyInRange = lastDocMin.woCompare( maxKey ) < 0 &&
lastDocMax.woCompare( maxKey ) >= 0;
if ( !maxKeyInRange ) {
*errMsg = stream() << "could not merge chunks, collection " << nss.ns()
<< " range ending at " << maxKey
<< " does not belong to shard " << shardingState.getShardName();
warning() << *errMsg << endl;
return false;
}
bool validRangeStartKey = firstDocMin.woCompare( minKey ) == 0;
bool validRangeEndKey = lastDocMax.woCompare( maxKey ) == 0;
if ( !validRangeStartKey || !validRangeEndKey ) {
*errMsg = stream() << "could not merge chunks, collection " << nss.ns()
<< " does not contain a chunk "
<< ( !validRangeStartKey ? "starting at " + minKey.toString() : "" )
<< ( !validRangeStartKey && !validRangeEndKey ? " or " : "" )
<< ( !validRangeEndKey ? "ending at " + maxKey.toString() : "" );
warning() << *errMsg << endl;
return false;
}
if ( chunksToMerge.size() == 1 ) {
*errMsg = stream() << "could not merge chunks, collection " << nss.ns()
<< " already contains chunk for " << rangeToString( minKey, maxKey );
warning() << *errMsg << endl;
return false;
}
bool holeInRange = false;
// Look for hole in range
ChunkType* prevChunk = *chunksToMerge.begin();
ChunkType* nextChunk = NULL;
for ( OwnedPointerVector<ChunkType>::const_iterator it = chunksToMerge.begin();
it != chunksToMerge.end(); ++it ) {
if ( it == chunksToMerge.begin() ) continue;
nextChunk = *it;
if ( prevChunk->getMax().woCompare( nextChunk->getMin() ) != 0 ) {
holeInRange = true;
break;
}
prevChunk = nextChunk;
}
if ( holeInRange ) {
dassert( NULL != nextChunk );
*errMsg = stream() << "could not merge chunks, collection " << nss.ns()
<< " has a hole in the range " << rangeToString( minKey, maxKey )
<< " at " << rangeToString( prevChunk->getMax(),
nextChunk->getMin() );
warning() << *errMsg << endl;
return false;
}
//
// Run apply ops command
//
BSONObj applyOpsCmd = buildApplyOpsCmd( chunksToMerge,
shardVersion,
mergeVersion );
bool ok;
BSONObj result;
try {
ScopedDbConnection conn( configLoc, 30.0 );
ok = conn->runCommand( "config", applyOpsCmd, result );
if ( !ok ) *errMsg = result.toString();
conn.done();
}
catch( const DBException& ex ) {
ok = false;
*errMsg = ex.toString();
}
if ( !ok ) {
*errMsg = stream() << "could not merge chunks for " << nss.ns()
<< ", writing to config failed" << causedBy( errMsg );
warning() << *errMsg << endl;
return false;
}
//
// Install merged chunk metadata
//
{
Lock::DBLock writeLk(txn->lockState(), nss.db(), newlm::MODE_X);
shardingState.mergeChunks(txn, nss.ns(), minKey, maxKey, mergeVersion);
}
//
// Log change
//
BSONObj mergeLogEntry = buildMergeLogEntry( chunksToMerge,
shardVersion,
mergeVersion );
configServer.logChange( "merge", nss.ns(), mergeLogEntry );
return true;
}
static Status parseGeoJSONPolygonCoordinates(const BSONElement& elem, S2Polygon* out) {
if (Array != elem.type()) {
return BAD_VALUE("Polygon coordinates must be an array");
}
OwnedPointerVector<S2Loop> loops;
Status status = Status::OK();
string err;
BSONObjIterator it(elem.Obj());
// Iterate all loops of the polygon.
while (it.more()) {
// Parse the array of vertices of a loop.
BSONElement coordinateElt = it.next();
vector<S2Point> points;
status = parseArrayOfCoordinates(coordinateElt, &points);
if (!status.isOK())
return status;
// Check if the loop is closed.
status = isLoopClosed(points, coordinateElt);
if (!status.isOK())
return status;
eraseDuplicatePoints(&points);
// Drop the duplicated last point.
points.resize(points.size() - 1);
// At least 3 vertices.
if (points.size() < 3) {
return BAD_VALUE(
"Loop must have at least 3 different vertices: " << coordinateElt.toString(false));
}
S2Loop* loop = new S2Loop(points);
loops.push_back(loop);
// Check whether this loop is valid.
// 1. At least 3 vertices.
// 2. All vertices must be unit length. Guaranteed by parsePoints().
// 3. Loops are not allowed to have any duplicate vertices.
// 4. Non-adjacent edges are not allowed to intersect.
if (!loop->IsValid(&err)) {
return BAD_VALUE("Loop is not valid: " << coordinateElt.toString(false) << " " << err);
}
// If the loop is more than one hemisphere, invert it.
loop->Normalize();
// Check the first loop must be the exterior ring and any others must be
// interior rings or holes.
if (loops.size() > 1 && !loops[0]->Contains(loop)) {
return BAD_VALUE(
"Secondary loops not contained by first exterior loop - "
"secondary loops must be holes: "
<< coordinateElt.toString(false)
<< " first loop: " << elem.Obj().firstElement().toString(false));
}
}
if (loops.empty()) {
return BAD_VALUE("Polygon has no loops.");
}
// Check if the given loops form a valid polygon.
// 1. If a loop contains an edge AB, then no other loop may contain AB or BA.
// 2. No loop covers more than half of the sphere.
// 3. No two loops cross.
if (!S2Polygon::IsValid(loops.vector(), &err))
return BAD_VALUE("Polygon isn't valid: " << err << " " << elem.toString(false));
// Given all loops are valid / normalized and S2Polygon::IsValid() above returns true.
// The polygon must be valid. See S2Polygon member function IsValid().
// Transfer ownership of the loops and clears loop vector.
out->Init(&loops.mutableVector());
// Check if every loop of this polygon shares at most one vertex with
// its parent loop.
if (!out->IsNormalized(&err))
// "err" looks like "Loop 1 shares more than one vertex with its parent loop 0"
return BAD_VALUE(err << ": " << elem.toString(false));
// S2Polygon contains more than one ring, which is allowed by S2, but not by GeoJSON.
//
// Loops are indexed according to a preorder traversal of the nesting hierarchy.
// GetLastDescendant() returns the index of the last loop that is contained within
// a given loop. We guarantee that the first loop is the exterior ring.
if (out->GetLastDescendant(0) < out->num_loops() - 1) {
return BAD_VALUE("Only one exterior polygon loop is allowed: " << elem.toString(false));
}
// In GeoJSON, only one nesting is allowed.
// The depth of a loop is set by polygon according to the nesting hierarchy of polygon,
// so the exterior ring's depth is 0, a hole in it is 1, etc.
for (int i = 0; i < out->num_loops(); i++) {
if (out->loop(i)->depth() > 1) {
return BAD_VALUE("Polygon interior loops cannot be nested: " << elem.toString(false));
}
}
return Status::OK();
}
