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Overview
| Comment: | Very small performance increase in sqlite3VdbeSetNumCols(). |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA3-256: |
8885b4461044ae8ecdfe1b9aa47f4aad |
| User & Date: | drh 2017-05-31 11:24:13 |
Context
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2017-05-31
| ||
| 13:27 | Remove a completely unnecessary memset() from the INSERT code generator. check-in: 7d58836b user: drh tags: trunk | |
| 11:24 | Very small performance increase in sqlite3VdbeSetNumCols(). check-in: 8885b446 user: drh tags: trunk | |
| 03:20 | Reorder fields in the PgHdr object for a performance increase. check-in: 326e63d7 user: drh tags: trunk | |
Changes
Changes to src/vdbeaux.c.
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/*
** Set the number of result columns that will be returned by this SQL
** statement. This is now set at compile time, rather than during
** execution of the vdbe program so that sqlite3_column_count() can
** be called on an SQL statement before sqlite3_step().
*/
void sqlite3VdbeSetNumCols(Vdbe *p, int nResColumn){
Mem *pColName;
int n;
sqlite3 *db = p->db;
releaseMemArray(p->aColName, p->nResColumn*COLNAME_N);
sqlite3DbFree(db, p->aColName);
n = nResColumn*COLNAME_N;
p->nResColumn = (u16)nResColumn;
p->aColName = pColName = (Mem*)sqlite3DbMallocRawNN(db, sizeof(Mem)*n );
if( p->aColName==0 ) return;
initMemArray(p->aColName, n, p->db, MEM_Null);
}
/*
** Set the name of the idx'th column to be returned by the SQL statement.
** zName must be a pointer to a nul terminated string.
**
** This call must be made after a call to sqlite3VdbeSetNumCols().
|
< > | | > | | |
2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 |
/*
** Set the number of result columns that will be returned by this SQL
** statement. This is now set at compile time, rather than during
** execution of the vdbe program so that sqlite3_column_count() can
** be called on an SQL statement before sqlite3_step().
*/
void sqlite3VdbeSetNumCols(Vdbe *p, int nResColumn){
int n;
sqlite3 *db = p->db;
if( p->nResColumn ){
releaseMemArray(p->aColName, p->nResColumn*COLNAME_N);
sqlite3DbFree(db, p->aColName);
}
n = nResColumn*COLNAME_N;
p->nResColumn = (u16)nResColumn;
p->aColName = (Mem*)sqlite3DbMallocRawNN(db, sizeof(Mem)*n );
if( p->aColName==0 ) return;
initMemArray(p->aColName, n, db, MEM_Null);
}
/*
** Set the name of the idx'th column to be returned by the SQL statement.
** zName must be a pointer to a nul terminated string.
**
** This call must be made after a call to sqlite3VdbeSetNumCols().
|