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Change the size of a mini-lookaside allocation to a macro (MINI_SZ) rather

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than a magic number (128).

FossilOrigin-Name: 5e1949bca998f3c8c23a8ebf01c7a2e7a2af1fdad43886271e1fe0f25411551d
This commit is contained in:
drh
2019-12-12 17:17:24 +00:00
parent 20d6c1fe1b
commit 0225d819c4
5 changed files with 19 additions and 16 deletions
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8
src/main.c
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@@ -720,9 +720,9 @@ static int setupLookaside(sqlite3 *db, void *pBuf, int sz, int cnt){
db->lookaside.pMiniFree = 0;
/* The arithmetic below causes the number of large lookaside slots to be 1/3
** the number of mini slots, based on the observation that 75% of allocations
** are <=128B.
** are <= MINI_SZ bytes.
*/
cnt = szAlloc/(3*128+sz);
cnt = szAlloc/(3*MINI_SZ+sz);
#endif
db->lookaside.sz = (u16)sz;
db->lookaside.szTrue = (u16)sz;
@@ -740,11 +740,11 @@ static int setupLookaside(sqlite3 *db, void *pBuf, int sz, int cnt){
#ifndef SQLITE_OMIT_MINI_LOOKASIDE
db->lookaside.pMiddle = p;
/* Fill the remainder of the buffer with mini slots */
while(p<=(LookasideSlot*)&((u8*)pStart)[szAlloc-128]){
while(p<=(LookasideSlot*)&((u8*)pStart)[szAlloc-MINI_SZ]){
p->pNext = db->lookaside.pMiniInit;
db->lookaside.pMiniInit = p;
db->lookaside.nSlot++;
p = (LookasideSlot*)&((u8*)p)[128];
p = (LookasideSlot*)&((u8*)p)[MINI_SZ];
}
#endif
db->lookaside.pEnd = p;