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Convert prefix queries to ranges ~20%+ speedup SERVER-611

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This commit is contained in:
Mathias Stearn
2010-02-25 21:42:46 -05:00
parent 621686366d
commit 5073a41103
3 changed files with 114 additions and 77 deletions
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151
db/queryutil.cpp
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@@ -24,85 +24,95 @@
#include "../util/unittest.h"
namespace mongo {
namespace {
/** returns a string that when used as a matcher, would match a super set of regex()
returns "" for complex regular expressions
used to optimize queries in some simple regex cases that start with '^'
*/
inline string simpleRegexHelper(const char* regex, const char* flags){
string r = "";
/** returns a string that when used as a matcher, would match a super set of regex()
returns "" for complex regular expressions
used to optimize queries in some simple regex cases that start with '^'
bool extended = false;
while (*flags){
switch (*(flags++)){
case 'm': // multiline
continue;
case 'x': // extended
extended = true;
break;
default:
return r; // cant use index
}
}
if purePrefix != NULL, sets it to whether the regex can be converted to a range query
*/
string simpleRegex(const char* regex, const char* flags, bool* purePrefix){
string r = "";
if ( *(regex++) != '^' )
return r;
if (purePrefix) *purePrefix = false;
stringstream ss;
while(*regex){
char c = *(regex++);
if ( c == '*' || c == '?' ){
// These are the only two symbols that make the last char optional
r = ss.str();
r = r.substr( 0 , r.size() - 1 );
return r; //breaking here fails with /^a?/
} else if (c == '\\'){
// slash followed by non-alphanumeric represents the following char
c = *(regex++);
if ((c >= 'A' && c <= 'Z') ||
(c >= 'a' && c <= 'z') ||
(c >= '0' && c <= '0') ||
(c == '\0'))
{
r = ss.str();
break;
} else {
ss << c;
}
} else if (strchr("^$.[|()+{", c)){
// list of "metacharacters" from man pcrepattern
r = ss.str();
break;
} else if (extended && c == '#'){
// comment
r = ss.str();
break;
} else if (extended && isspace(c)){
bool extended = false;
while (*flags){
switch (*(flags++)){
case 'm': // multiline
continue;
case 'x': // extended
extended = true;
break;
default:
return r; // cant use index
}
}
if ( *(regex++) != '^' )
return r;
stringstream ss;
while(*regex){
char c = *(regex++);
if ( c == '*' || c == '?' ){
// These are the only two symbols that make the last char optional
r = ss.str();
r = r.substr( 0 , r.size() - 1 );
return r; //breaking here fails with /^a?/
} else if (c == '\\'){
// slash followed by non-alphanumeric represents the following char
c = *(regex++);
if ((c >= 'A' && c <= 'Z') ||
(c >= 'a' && c <= 'z') ||
(c >= '0' && c <= '0') ||
(c == '\0'))
{
r = ss.str();
break;
} else {
// self-matching char
ss << c;
}
}
if ( r.size() == 0 && *regex == 0 )
} else if (strchr("^$.[|()+{", c)){
// list of "metacharacters" from man pcrepattern
r = ss.str();
return r;
}
inline string simpleRegex(const BSONElement& e){
switch(e.type()){
case RegEx:
return simpleRegexHelper(e.regex(), e.regexFlags());
case Object:{
BSONObj o = e.embeddedObject();
return simpleRegexHelper(o["$regex"].valuestrsafe(), o["$options"].valuestrsafe());
}
default: assert(false); return ""; //return squashes compiler warning
break;
} else if (extended && c == '#'){
// comment
r = ss.str();
break;
} else if (extended && isspace(c)){
continue;
} else {
// self-matching char
ss << c;
}
}
if ( r.empty() && *regex == 0 ){
r = ss.str();
if (purePrefix) *purePrefix = !r.empty();
}
return r;
}
inline string simpleRegex(const BSONElement& e){
switch(e.type()){
case RegEx:
return simpleRegex(e.regex(), e.regexFlags());
case Object:{
BSONObj o = e.embeddedObject();
return simpleRegex(o["$regex"].valuestrsafe(), o["$options"].valuestrsafe());
}
default: assert(false); return ""; //return squashes compiler warning
}
}
string simpleRegexEnd( string regex ) {
++regex[ regex.length() - 1 ];
return regex;
}
FieldRange::FieldRange( const BSONElement &e, bool isNot, bool optimize ) {
// NOTE with $not, we could potentially form a complementary set of intervals.
@@ -328,11 +338,6 @@ namespace mongo {
return *this;
}
string FieldRange::simpleRegexEnd( string regex ) {
++regex[ regex.length() - 1 ];
return regex;
}
BSONObj FieldRange::addObj( const BSONObj &o ) {
objData_.push_back( o );
return o;