mirror of
https://github.com/mongodb/mongo.git
synced 2024-11-30 00:56:44 +01:00
593 lines
19 KiB
C++
593 lines
19 KiB
C++
// shardkey.cpp
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/**
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* Copyright (C) 2008 10gen Inc.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License, version 3,
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "stdafx.h"
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#include "shard.h"
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#include "../db/jsobj.h"
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#include "../util/unittest.h"
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/**
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TODO: this only works with numbers right now
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this is very temporary, need to make work with anything
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*/
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namespace mongo {
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inline BSONObj ShardKeyPattern::extractKey(const BSONObj& from) const {
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return from.extractFields(pattern);
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}
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BSONObj ShardKeyPattern::globalMin() const {
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BSONObjBuilder b;
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BSONElement e = pattern.firstElement();
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b.appendMinKey(e.fieldName());
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return b.obj();
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}
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BSONObj ShardKeyPattern::globalMax() const {
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BSONObjBuilder b;
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BSONElement e = pattern.firstElement();
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b.appendMaxKey(e.fieldName());
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return b.obj();
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}
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int ShardKeyPattern::compare( const BSONObj& lObject , const BSONObj& rObject ) {
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BSONObj L = extractKey(lObject);
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uassert("left object doesn't have shard key", !L.isEmpty());
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BSONObj R = extractKey(rObject);
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uassert("right object doesn't have shard key", !R.isEmpty());
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return L.woCompare(R);
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}
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// return X / 2
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OID div2(OID X) {
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unsigned char *x = (unsigned char *) &X;
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unsigned char carry = 0;
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for(int i = 0; i <= 11; i++ ) {
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unsigned char ncarry = (x[i] & 1) << 7;
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x[i] = (x[i] >> 1) | carry;
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carry = ncarry;
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}
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return X;
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}
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OID operator+(OID X, OID Y) {
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OID Res;
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unsigned char *res = (unsigned char *) &Res;
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unsigned char *x = (unsigned char *) &X;
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unsigned char *y = (unsigned char *) &Y;
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int carry = 0;
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for( int i = 11; i >= 0; i-- ) {
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int a = x[i];
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int b = y[i];
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int c = a+b+carry;
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if( c >= 256 ) {
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c -= 256;
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carry = 1;
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}
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else
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carry = 0;
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assert( c >= 0 && c <= 255 );
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res[i] = (unsigned char) c;
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}
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assert( carry == 0 );
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return Res;
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}
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// return X-Y
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OID operator-(OID X, OID Y) {
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OID Res;
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unsigned char *res = (unsigned char *) &Res;
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unsigned char *x = (unsigned char *) &X;
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unsigned char *y = (unsigned char *) &Y;
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// oid's are in a big endian style order, so we do this byte by byte
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int carry = 0;
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for( int i = 11; i >= 0; i-- ) {
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int a = x[i];
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int b = y[i];
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int c = a-b-carry;
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if( c < 0 ) {
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c += 256;
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carry = 1;
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}
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else
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carry = 0;
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assert( c >= 0 && c <= 255 );
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res[i] = (unsigned char) c;
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}
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assert( carry == 0 );
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return Res;
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}
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OID averageOIDs(OID& left, OID& right) {
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// return add(left, div2(diff(right,left)));
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return left + div2(right-left);
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}
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string middleString(const char *_left, const char *_right) {
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const unsigned char *left = (const unsigned char *) _left;
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const unsigned char *right = (const unsigned char *) _right;
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unsigned char *x = (unsigned char *) malloc(strlen(_left)+1);
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strcpy((char *) x, (char *) left);
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unsigned char *l = x;
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const unsigned char *r = right;
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while( *l == *r ) {
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assert( *l ); // can't be exactly same string
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l++; r++;
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}
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// note *l might be null e.g. "xxx\0", "xxxy..."
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assert( *r );
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int ch = (((int) *l) + ((int) *r)) / 2;
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string s = string((const char *) x, l-x) + (char) ch;
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while( s <= (const char *) left ) {
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// we rounded down to the same old value. keep adding chars
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int ch = (((int) *++l) + 255) / 2;
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s += ch;
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assert( s < (const char *) right );
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}
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// cout << '"' << left << '"' << ' ' << '"' << right << '"' << ' ' << '"' << s << '"' << endl;
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return s;
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}
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/* average two element's values, must be the same type
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range is closed on the left and open on the right, so left must neever touch the
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right value: if they get to be adjacent, the left value is returned.
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*/
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void averageValues(BSONObjBuilder&b, int type, BSONElement& l, BSONElement& r) {
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const char *fn = l.fieldName();
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switch( type ) {
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case MaxKey:
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case jstNULL:
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case MinKey:
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case EOO:
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massert("unexpected type in averageValues", false);
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break;
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case NumberDouble:
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{
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double x = l.number();
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double y = r.number();
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assert( y >= x );
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b.append(fn, x + (y - x)/2);
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break;
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}
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case String:
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b.append(fn, middleString(l.valuestr(), r.valuestr()));
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break;
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case jstOID:
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b.append(fn, averageOIDs(l.__oid(), r.__oid()));
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break;
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case Bool:
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b.append(l);
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break;
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case Date:
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{
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unsigned long long x = l.date();
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unsigned long long y = r.date();
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assert( y >= x );
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b.appendDate(fn, x + (y - x)/2);
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break;
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}
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case NumberInt:
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{
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int x = (int) l.number();
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int y = (int) r.number();
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assert( y >= x );
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b.append(fn, x + (y - x)/2);
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break;
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}
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default:
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{
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stringstream ss;
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ss << "BSON type " << type << " not yet supported in shard keys";
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uasserted( ss.str() );
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}
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}
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}
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int nextType(int t) {
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switch( t ) {
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case MinKey: return NumberDouble;
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case NumberDouble: return String;
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case String: return jstOID;
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case jstOID: return Bool;
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case Bool: return Date;
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case Date: return jstNULL;
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case jstNULL: return NumberInt;
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case NumberInt: return MaxKey;
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default:
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uassert("type not supported by sharding [nextType]", false);
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}
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return EOO;
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}
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BSONElement largestElementForType(int t, BSONObjBuilder& b) {
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switch( t ) {
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case MinKey: b.appendMinKey(""); break;
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case NumberDouble: b.append("", numeric_limits< double >::min()); break;
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case String: b.append("", ""); break;
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case jstOID:
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{
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OID o;
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memset(&o, 0, sizeof(o));
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b.appendOID("", &o);
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break;
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}
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case Bool: b.appendBool("", false); break;
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case Date: b.appendDate("", 0); break;
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case jstNULL: b.appendNull("");
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case NumberInt: b.append("", numeric_limits<int>::min()); break;
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default:
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uassert("type not supported by sharding [seft]", false);
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}
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return b.done().firstElement();
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}
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BSONElement smallestElementForType(int t, BSONObjBuilder& b) {
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switch( t ) {
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case MinKey: b.appendMinKey(""); break;
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case NumberDouble: b.append("", numeric_limits< double >::min()); break;
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case String: b.append("", ""); break;
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case jstOID:
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{
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OID o;
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memset(&o, 0, sizeof(o));
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b.appendOID("", &o);
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break;
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}
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case Bool: b.appendBool("", false); break;
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case Date: b.appendDate("", 0); break;
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case jstNULL: b.appendNull("");
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case NumberInt: b.append("", numeric_limits<int>::min()); break;
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default:
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uassert("type not supported by sharding [seft]", false);
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}
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return b.done().firstElement();
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}
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// assure l != r value before calling
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void middleVal(BSONObjBuilder& b, BSONElement& l, BSONElement& r) {
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int lt = l.type();
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int rt = r.type();
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int d = rt - lt;
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assert( d >= 0 );
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if( d > 0 ) {
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int nextt = nextType(lt);
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BSONObjBuilder B, BB;
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BSONElement nexte = smallestElementForType(nextt, B);
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if( nextt == rt && compareElementValues(nexte, r) == 0 ) {
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// too big.
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nexte = largestElementForType(nextt, BB);
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}
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b.appendAs(nexte, l.fieldName());
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return;
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}
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// same type
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averageValues(b, lt, l, r);
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}
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BSONObj ShardKeyPattern::middle( BSONObj &lo , BSONObj &ro ) {
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BSONObj L = extractKey(lo);
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BSONObj R = extractKey(ro);
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BSONElement l = L.firstElement();
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BSONElement r = R.firstElement();
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if( l == r || l.eoo() || r.eoo() )
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return L;
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BSONObjBuilder b;
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massert("not done for compound patterns", patternfields.size() == 1);
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middleVal(b, l, r);
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BSONObj res = b.obj();
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if( res.woEqual(ro) ) {
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// range is minimal, i.e., two adjacent values. as RHS is open,
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// return LHS
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return lo;
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}
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/* compound:
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BSONObjIterator li(L);
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BSONObjIterator ri(R);
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while( 1 ) {
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}
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*/
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return res;
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}
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bool ShardKeyPattern::hasShardKey( const BSONObj& obj ) {
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/* this is written s.t. if obj has lots of fields, if the shard key fields are early,
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it is fast. so a bit more work to try to be semi-fast.
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*/
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BSONObjIterator i(obj);
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int n = patternfields.size();
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while( 1 ) {
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BSONElement e = i.next();
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if( e.eoo() )
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return false;
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if( patternfields.find(e.fieldName()) == patternfields.end() )
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continue;
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if( --n == 0 )
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break;
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}
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return true;
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}
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/** @return true if shard s is relevant for query q.
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Example:
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q: { x : 3 }
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*this: { x : 1 }
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s: x:2..x:7
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-> true
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*/
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bool ShardKeyPattern::relevantForQuery( const BSONObj& query , Shard * shard ){
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if ( ! hasShardKey( query ) ){
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// if the shard key isn't in the query, then we have to go everywhere
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// therefore this shard is relevant
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return true;
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}
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massert("not done for compound patterns", patternfields.size() == 1);
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/* question: are patterns ever { field : -1 } ? */
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/* might be easiest here to use a JSMatcher plus a little extra */
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//string f = *patternfields.begin();
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BSONObj v = extractKey( query );
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BSONElement e = v.firstElement();
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massert( "regex shard support not done yet", e.type() != RegEx );
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if( e.type() == Object ) {
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massert( "gt/lt etc. support not done yet", e.embeddedObject().firstElement().fieldName()[0] != '$');
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}
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/* question: areKey kthese already proper keys, and extractKey call is unnecessary? */
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// BSONObj L = extractKey(shard->getMin());
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// BSONObj R = extractKey(shard->getMax());
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/* todo:
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_ $gt/$lt
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_ $ne
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_ regex
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*/
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return shard->contains(v);
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}
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/**
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returns a query that filters results only for the range desired, i.e. returns
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{ $gte : keyval(min), $lt : keyval(max) }
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*/
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void ShardKeyPattern::getFilter( BSONObjBuilder& b , const BSONObj& min, const BSONObj& max ){
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massert("not done for compound patterns", patternfields.size() == 1);
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BSONObjBuilder temp;
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temp.appendAs( extractKey(min).firstElement(), "$gte" );
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temp.appendAs( extractKey(max).firstElement(), "$lt" );
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b.append( patternfields.begin()->c_str(), temp.obj() );
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}
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/**
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Example
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sort: { ts: -1 }
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*this: { ts:1 }
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-> -1
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@return
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0 if sort either doesn't have all the fields or has extra fields
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< 0 if sort is descending
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> 1 if sort is ascending
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*/
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int ShardKeyPattern::canOrder( const BSONObj& sort ){
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// e.g.:
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// sort { a : 1 , b : -1 }
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// pattern { a : -1, b : 1, c : 1 }
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// -> -1
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int dir = 0;
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BSONObjIterator s(sort);
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BSONObjIterator p(pattern);
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while( 1 ) {
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BSONElement e = s.next();
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if( e.eoo() )
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break;
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if( !p.more() )
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return 0;
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BSONElement ep = p.next();
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bool same = e == ep;
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if( !same ) {
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if( strcmp(e.fieldName(), ep.fieldName()) != 0 )
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return 0;
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// same name, but opposite direction
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if( dir == -1 )
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; // ok
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else if( dir == 1 )
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return 0; // wrong direction for a 2nd field
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else // dir == 0, initial pass
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dir = -1;
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}
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else {
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// fields are the same
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if( dir == -1 )
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return 0; // wrong direction
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dir = 1;
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}
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}
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return dir;
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}
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string ShardKeyPattern::toString() const {
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return pattern.toString();
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}
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class ShardKeyUnitTest : public UnitTest {
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public:
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void hsk() {
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BSONObj x = fromjson("{ zid : \"abcdefg\", num: 1.0, name: \"eliot\" }");
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ShardKeyPattern k( BSON( "num" << 1 ) );
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assert( k.hasShardKey(x) );
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}
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void rfq() {
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if( 1 )
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return;// can't do, manager is null.
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ShardKeyPattern k( BSON( "key" << 1 ) );
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BSONObj q = BSON( "key" << 3 );
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Shard s(0);
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BSONObj z = fromjson("{ ns : \"alleyinsider.fs.chunks\" , min : {key:2} , max : {key:20} , server : \"localhost:30001\" }");
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s.unserialize(z);
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cout << k.relevantForQuery(q, &s) << endl;
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}
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void getfilt() {
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ShardKeyPattern k( BSON( "key" << 1 ) );
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BSONObjBuilder b;
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k.getFilter(b, fromjson("{z:3,key:30}"), fromjson("{key:90}"));
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BSONObj x = fromjson("{ key: { $gte: 30.0, $lt: 90.0 } }");
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assert( x.woEqual(b.obj()) );
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}
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void mid(const char *a, const char *b) {
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ShardKeyPattern k( BSON( "key" << 1 ) );
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BSONObj A = fromjson(a);
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BSONObj B = fromjson(b);
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BSONObj x = k.middle(A, B);
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assert( A.woCompare(x) < 0 );
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assert( x.woCompare(B) < 0 );
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}
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void testMiddle() {
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mid( "{key:10}", "{key:30}" );
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mid( "{key:10}", "{key:null}" );
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mid( "{key:\"Jane\"}", "{key:\"Tom\"}" );
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BSONObjBuilder b;
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b.appendMinKey("k");
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BSONObj min = b.obj();
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BSONObjBuilder b2;
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b2.appendMaxKey("k");
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BSONObj max = b2.obj();
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ShardKeyPattern k( BSON( "k" << 1 ) );
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// cout << min.toString() << endl;
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BSONObj m = k.middle(min, max);
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// cout << m << endl;
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BSONObj n = k.middle(m, max);
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// cout << n << endl;
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BSONObj p = k.middle(min, m);
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// cout << "\n" << min.toString() << " " << m.toString() << endl;
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// cout << p << endl;
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}
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void div(const char *a, const char *res) {
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OID A,RES;
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A.init(a);
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RES = div2(A);
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assert( RES.str() == res );
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}
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void diff(const char *a, const char *b, const char *res) {
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OID A,B,RES;
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A.init(a); B.init(b);
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RES = A - B;
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assert( RES.str() == res );
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assert( RES + B == A );
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}
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void oid() {
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diff("800000000000000000000000", "000000000000000000000001", "7fffffffffffffffffffffff");
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diff("800000000000000000000001", "800000000000000000000000", "000000000000000000000001");
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diff("800000000000000000000000", "800000000000000000000000", "000000000000000000000000");
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div("800000000000000000000000", "400000000000000000000000");
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div("010000000000000000000000", "008000000000000000000000");
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}
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void checkstr(const char *a, const char *b) {
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string s = middleString(a, b);
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assert( s > a );
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|
assert( s < b );
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|
}
|
|
void ms() {
|
|
checkstr("a\377", "b");
|
|
checkstr("a\377\377", "b");
|
|
checkstr("a", "b");
|
|
checkstr("a","c");
|
|
checkstr("aa","ac");
|
|
checkstr("aac","ac");
|
|
checkstr("aa","aat");
|
|
checkstr("aat", "acq");
|
|
}
|
|
void testCanOrder() {
|
|
ShardKeyPattern k( fromjson("{a:1,b:-1,c:1}") );
|
|
assert( k.canOrder( fromjson("{a:1}") ) == 1 );
|
|
assert( k.canOrder( fromjson("{a:-1}") ) == -1 );
|
|
assert( k.canOrder( fromjson("{a:1,b:-1,c:1}") ) == 1 );
|
|
assert( k.canOrder( fromjson("{a:1,b:1}") ) == 0 );
|
|
assert( k.canOrder( fromjson("{a:-1,b:1}") ) == -1 );
|
|
}
|
|
void run(){
|
|
oid();
|
|
ms();
|
|
|
|
ShardKeyPattern k( BSON( "key" << 1 ) );
|
|
|
|
BSONObj min = k.globalMin();
|
|
|
|
// cout << min.jsonString(TenGen) << endl;
|
|
|
|
BSONObj max = k.globalMax();
|
|
|
|
BSONObj k1 = BSON( "key" << 5 );
|
|
|
|
assert( k.compare( min , max ) < 0 );
|
|
assert( k.compare( min , k1 ) < 0 );
|
|
assert( k.compare( max , min ) > 0 );
|
|
assert( k.compare( min , min ) == 0 );
|
|
|
|
hsk();
|
|
assert( k.hasShardKey( k1 ) );
|
|
assert( ! k.hasShardKey( BSON( "key2" << 1 ) ) );
|
|
|
|
BSONObj a = k1;
|
|
BSONObj b = BSON( "key" << 999 );
|
|
|
|
assert( k.compare(a,b) < 0 );
|
|
|
|
assert( k.compare(a,k.middle(a,a)) == 0 );
|
|
assert( k.compare(a,k.middle(a,b)) <= 0 );
|
|
assert( k.compare(k.middle(a,b),b) <= 0 );
|
|
|
|
assert( k.canOrder( fromjson("{key:1}") ) == 1 );
|
|
assert( k.canOrder( fromjson("{zz:1}") ) == 0 );
|
|
assert( k.canOrder( fromjson("{key:-1}") ) == -1 );
|
|
|
|
testCanOrder();
|
|
testMiddle();
|
|
getfilt();
|
|
rfq();
|
|
// add middle multitype tests
|
|
}
|
|
} shardKeyTest;
|
|
|
|
} // namespace mongo
|