redict/src/listpack.h
Viktor Söderqvist 8a315fc285
When converting a set to dict, presize for one more element to be added (#11559)
In most cases when a listpack or intset is converted to a dict, the conversion
is trigged when adding an element. The extra element is added after conversion
to dict (in all cases except when the conversion is triggered by
set-max-intset-entries being reached).

If set-max-listpack-entries is set to a power of two, let's say 128, when
adding the 129th element, the 128 element listpack is first converted to a dict
with a hashtable presized for 128 elements. After converting to dict, the 129th
element is added to the dict which immediately triggers incremental rehashing
to size 256.

This commit instead presizes the dict to one more element, with the assumption
that conversion to dict is followed by adding another element, so the dict
doesn't immediately need rehashing.

Co-authored-by: sundb <sundbcn@gmail.com>
Co-authored-by: Oran Agra <oran@redislabs.com>
2022-12-06 11:25:51 +02:00

107 lines
5.4 KiB
C

/* Listpack -- A lists of strings serialization format
*
* This file implements the specification you can find at:
*
* https://github.com/antirez/listpack
*
* Copyright (c) 2017, Salvatore Sanfilippo <antirez at gmail dot com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of Redis nor the names of its contributors may be used
* to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef __LISTPACK_H
#define __LISTPACK_H
#include <stdlib.h>
#include <stdint.h>
#define LP_INTBUF_SIZE 21 /* 20 digits of -2^63 + 1 null term = 21. */
/* lpInsert() where argument possible values: */
#define LP_BEFORE 0
#define LP_AFTER 1
#define LP_REPLACE 2
/* Each entry in the listpack is either a string or an integer. */
typedef struct {
/* When string is used, it is provided with the length (slen). */
unsigned char *sval;
uint32_t slen;
/* When integer is used, 'sval' is NULL, and lval holds the value. */
long long lval;
} listpackEntry;
unsigned char *lpNew(size_t capacity);
void lpFree(unsigned char *lp);
unsigned char* lpShrinkToFit(unsigned char *lp);
unsigned char *lpInsertString(unsigned char *lp, unsigned char *s, uint32_t slen,
unsigned char *p, int where, unsigned char **newp);
unsigned char *lpInsertInteger(unsigned char *lp, long long lval,
unsigned char *p, int where, unsigned char **newp);
unsigned char *lpPrepend(unsigned char *lp, unsigned char *s, uint32_t slen);
unsigned char *lpPrependInteger(unsigned char *lp, long long lval);
unsigned char *lpAppend(unsigned char *lp, unsigned char *s, uint32_t slen);
unsigned char *lpAppendInteger(unsigned char *lp, long long lval);
unsigned char *lpReplace(unsigned char *lp, unsigned char **p, unsigned char *s, uint32_t slen);
unsigned char *lpReplaceInteger(unsigned char *lp, unsigned char **p, long long lval);
unsigned char *lpDelete(unsigned char *lp, unsigned char *p, unsigned char **newp);
unsigned char *lpDeleteRangeWithEntry(unsigned char *lp, unsigned char **p, unsigned long num);
unsigned char *lpDeleteRange(unsigned char *lp, long index, unsigned long num);
unsigned char *lpBatchDelete(unsigned char *lp, unsigned char **ps, unsigned long count);
unsigned char *lpMerge(unsigned char **first, unsigned char **second);
unsigned char *lpDup(unsigned char *lp);
unsigned long lpLength(unsigned char *lp);
unsigned char *lpGet(unsigned char *p, int64_t *count, unsigned char *intbuf);
unsigned char *lpGetValue(unsigned char *p, unsigned int *slen, long long *lval);
unsigned char *lpFind(unsigned char *lp, unsigned char *p, unsigned char *s, uint32_t slen, unsigned int skip);
unsigned char *lpFirst(unsigned char *lp);
unsigned char *lpLast(unsigned char *lp);
unsigned char *lpNext(unsigned char *lp, unsigned char *p);
unsigned char *lpPrev(unsigned char *lp, unsigned char *p);
size_t lpBytes(unsigned char *lp);
size_t lpEstimateBytesRepeatedInteger(long long lval, unsigned long rep);
unsigned char *lpSeek(unsigned char *lp, long index);
typedef int (*listpackValidateEntryCB)(unsigned char *p, unsigned int head_count, void *userdata);
int lpValidateIntegrity(unsigned char *lp, size_t size, int deep,
listpackValidateEntryCB entry_cb, void *cb_userdata);
unsigned char *lpValidateFirst(unsigned char *lp);
int lpValidateNext(unsigned char *lp, unsigned char **pp, size_t lpbytes);
unsigned int lpCompare(unsigned char *p, unsigned char *s, uint32_t slen);
void lpRandomPair(unsigned char *lp, unsigned long total_count, listpackEntry *key, listpackEntry *val);
void lpRandomPairs(unsigned char *lp, unsigned int count, listpackEntry *keys, listpackEntry *vals);
unsigned int lpRandomPairsUnique(unsigned char *lp, unsigned int count, listpackEntry *keys, listpackEntry *vals);
void lpRandomEntries(unsigned char *lp, unsigned int count, listpackEntry *entries);
unsigned char *lpNextRandom(unsigned char *lp, unsigned char *p, unsigned int *index,
unsigned int remaining, int even_only);
int lpSafeToAdd(unsigned char* lp, size_t add);
void lpRepr(unsigned char *lp);
#ifdef REDIS_TEST
int listpackTest(int argc, char *argv[], int flags);
#endif
#endif