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Avoid initializing the column-cache section of the Parse object, since entries

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in the cache will be initialized as they are used, and avoiding the initial
memset() saves many CPU cycles.

FossilOrigin-Name: 63cf7eafae5c3c1379edf416c5157010c7c120b5
This commit is contained in:
drh
2016-09-30 22:24:29 +00:00
parent 94881d732b
commit cd9af608e1
5 changed files with 38 additions and 23 deletions
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30
src/sqliteInt.h
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@@ -2904,14 +2904,6 @@ struct Parse {
int iCacheCnt; /* Counter used to generate aColCache[].lru values */
int nLabel; /* Number of labels used */
int *aLabel; /* Space to hold the labels */
struct yColCache {
int iTable; /* Table cursor number */
i16 iColumn; /* Table column number */
u8 tempReg; /* iReg is a temp register that needs to be freed */
int iLevel; /* Nesting level */
int iReg; /* Reg with value of this column. 0 means none. */
int lru; /* Least recently used entry has the smallest value */
} aColCache[SQLITE_N_COLCACHE]; /* One for each column cache entry */
ExprList *pConstExpr;/* Constant expressions */
Token constraintName;/* Name of the constraint currently being parsed */
yDbMask writeMask; /* Start a write transaction on these databases */
@@ -2940,6 +2932,20 @@ struct Parse {
u8 eOrconf; /* Default ON CONFLICT policy for trigger steps */
u8 disableTriggers; /* True to disable triggers */
/* The column cache comes at the end of the recursive section
** When initializing a new Parse object, the header above, and
** the non-recursive part that follows the column cache both need
** to be zeroed. But the column cache itself does not need zeroing
*/
struct yColCache {
int iTable; /* Table cursor number */
i16 iColumn; /* Table column number */
u8 tempReg; /* iReg is a temp register that needs to be freed */
int iLevel; /* Nesting level */
int iReg; /* Reg with value of this column. 0 means none. */
int lru; /* Least recently used entry has the smallest value */
} aColCache[SQLITE_N_COLCACHE]; /* One for each column cache entry */
/************************************************************************
** Above is constant between recursions. Below is reset before and after
** each recursion. The boundary between these two regions is determined
@@ -2978,6 +2984,14 @@ struct Parse {
With *pWithToFree; /* Free this WITH object at the end of the parse */
};
/*
** Sizes and pointers of various parts of the Parse object.
*/
#define PARSE_HDR_SZ offsetof(Parse,aColCache) /* Recursive part w/o aColCache*/
#define PARSE_RECURSE_SZ offsetof(Parse,nVar) /* Recursive part */
#define PARSE_TAIL_SZ (sizeof(Parse)-PARSE_RECURSE_SZ) /* Non-recursive part */
#define PARSE_TAIL(X) (((char*)(X))+PARSE_RECURSE_SZ) /* Pointer to tail */
/*
** Return true if currently inside an sqlite3_declare_vtab() call.
*/