@ -82,6 +82,9 @@ DECLARE_uint64(seed);
DECLARE_bool ( read_only ) ;
DECLARE_int64 ( max_key ) ;
DECLARE_double ( hot_key_alpha ) ;
DECLARE_int32 ( max_key_len ) ;
DECLARE_string ( key_len_percent_dist ) ;
DECLARE_int32 ( key_window_scale_factor ) ;
DECLARE_int32 ( column_families ) ;
DECLARE_string ( options_file ) ;
DECLARE_int64 ( active_width ) ;
@ -351,7 +354,7 @@ inline bool GetNextPrefix(const rocksdb::Slice& src, std::string* v) {
# endif
// convert long to a big-endian slice key
extern inline std : : string Key ( int64_t val ) {
extern inline std : : string GetStringFromInt ( int64_t val ) {
std : : string little_endian_key ;
std : : string big_endian_key ;
PutFixed64 ( & little_endian_key , val ) ;
@ -363,16 +366,110 @@ extern inline std::string Key(int64_t val) {
return big_endian_key ;
}
// A struct for maintaining the parameters for generating variable length keys
struct KeyGenContext {
// Number of adjacent keys in one cycle of key lengths
uint64_t window ;
// Number of keys of each possible length in a given window
std : : vector < uint64_t > weights ;
} ;
extern KeyGenContext key_gen_ctx ;
// Generate a variable length key string from the given int64 val. The
// order of the keys is preserved. The key could be anywhere from 8 to
// max_key_len * 8 bytes.
// The algorithm picks the length based on the
// offset of the val within a configured window and the distribution of the
// number of keys of various lengths in that window. For example, if x, y, x are
// the weights assigned to each possible key length, the keys generated would be
// - {0}...{x-1}
// {(x-1),0}..{(x-1),(y-1)},{(x-1),(y-1),0}..{(x-1),(y-1),(z-1)} and so on.
// Additionally, a trailer of 0-7 bytes could be appended.
extern inline std : : string Key ( int64_t val ) {
uint64_t window = key_gen_ctx . window ;
size_t levels = key_gen_ctx . weights . size ( ) ;
std : : string key ;
for ( size_t level = 0 ; level < levels ; + + level ) {
uint64_t weight = key_gen_ctx . weights [ level ] ;
uint64_t offset = static_cast < uint64_t > ( val ) % window ;
uint64_t mult = static_cast < uint64_t > ( val ) / window ;
uint64_t pfx = mult * weight + ( offset > = weight ? weight - 1 : offset ) ;
key . append ( GetStringFromInt ( pfx ) ) ;
if ( offset < weight ) {
// Use the bottom 3 bits of offset as the number of trailing 'x's in the
// key. If the next key is going to be of the next level, then skip the
// trailer as it would break ordering. If the key length is already at max,
// skip the trailer.
if ( offset < weight - 1 & & level < levels - 1 ) {
size_t trailer_len = offset & 0x7 ;
key . append ( trailer_len , ' x ' ) ;
}
break ;
}
val = offset - weight ;
window - = weight ;
}
return key ;
}
// Given a string key, map it to an index into the expected values buffer
extern inline bool GetIntVal ( std : : string big_endian_key , uint64_t * key_p ) {
unsigned int size_key = sizeof ( * key_p ) ;
assert ( big_endian_key . size ( ) = = size_key ) ;
size_t levels = key_gen_ctx . weights . size ( ) ;
size_t size_key = big_endian_key . size ( ) ;
std : : vector < uint64_t > prefixes ;
// Trim the key to multiple of 8 bytes
size_key & = ~ 7 ;
assert ( size_key < = levels * sizeof ( uint64_t ) ) ;
// Pad with zeros to make it a multiple of 8. This function may be called
// with a prefix, in which case we return the first index that falls
// inside or outside that prefix, dependeing on whether the prefix is
// the start of upper bound of a scan
unsigned int pad = sizeof ( uint64_t ) - ( size_key % sizeof ( uint64_t ) ) ;
if ( pad < sizeof ( uint64_t ) ) {
big_endian_key . append ( pad , ' \0 ' ) ;
}
std : : string little_endian_key ;
little_endian_key . resize ( size_key ) ;
for ( size_t i = 0 ; i < size_key ; + + i ) {
little_endian_key [ i ] = big_endian_key [ size_key - 1 - i ] ;
for ( size_t level = 0 ; level < size_key ; level + = sizeof ( int64_t ) ) {
size_t start = level * sizeof ( int64_t ) ;
size_t end = ( level + 1 ) * sizeof ( int64_t ) ;
for ( size_t i = start ; i < end ; + + i ) {
little_endian_key [ i ] = big_endian_key [ end - 1 - i ] ;
}
Slice little_endian_slice =
Slice ( & little_endian_key [ start ] , sizeof ( int64_t ) ) ;
uint64_t pfx ;
if ( ! GetFixed64 ( & little_endian_slice , & pfx ) ) {
return false ;
}
prefixes . emplace_back ( pfx ) ;
}
uint64_t key = 0 ;
for ( size_t i = 0 ; i < prefixes . size ( ) ; + + i ) {
uint64_t pfx = prefixes [ i ] ;
key + = ( pfx / key_gen_ctx . weights [ i ] ) * key_gen_ctx . window +
pfx % key_gen_ctx . weights [ i ] ;
}
* key_p = key ;
return true ;
}
extern inline uint64_t GetPrefixKeyCount ( const std : : string & prefix ,
const std : : string & ub ) {
uint64_t start = 0 ;
uint64_t end = 0 ;
if ( ! GetIntVal ( prefix , & start ) | | ! GetIntVal ( ub , & end ) ) {
return 0 ;
}
Slice little_endian_slice = Slice ( little_endian_key ) ;
return GetFixed64 ( & little_endian_slice , key_p ) ;
return end - start ;
}
extern inline std : : string StringToHex ( const std : : string & str ) {
anand76
5 years ago
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