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Add the "colUsed" field to the sqlite3_index_info structure passed to virtual table xBestIndex methods. To indicate the subset of the virtual table columns that may be required by the current scan.

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FossilOrigin-Name: 116b206494eb8ba963c7c5acfbf9e7b6db11c79c
This commit is contained in:
dan
2015-11-26 19:33:41 +00:00
parent fab1d401f8
commit 1acb539f4c
11 changed files with 267 additions and 87 deletions
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38
src/test8.c
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@@ -745,6 +745,34 @@ static void string_concat(char **pzStr, char *zAppend, int doFree, int *pRc){
}
}
/*
** This function returns a pointer to an sqlite3_malloc()ed buffer
** containing the select-list (the thing between keywords SELECT and FROM)
** to query the underlying real table with for the scan described by
** argument pIdxInfo.
**
** If the current SQLite version is earlier than 3.10.0, this is just "*"
** (select all columns). Or, for version 3.10.0 and greater, the list of
** columns identified by the pIdxInfo->colUsed mask.
*/
static char *echoSelectList(echo_vtab *pTab, sqlite3_index_info *pIdxInfo){
char *zRet = 0;
if( sqlite3_libversion_number()<3010000 ){
zRet = sqlite3_mprintf(", *");
}else{
int i;
for(i=0; i<pTab->nCol; i++){
if( pIdxInfo->colUsed & ((sqlite3_uint64)1 << (i>=63 ? 63 : i)) ){
zRet = sqlite3_mprintf("%z, %s", zRet, pTab->aCol[i]);
}else{
zRet = sqlite3_mprintf("%z, NULL", zRet);
}
if( !zRet ) break;
}
}
return zRet;
}
/*
** The echo module implements the subset of query constraints and sort
** orders that may take advantage of SQLite indices on the underlying
@@ -770,6 +798,7 @@ static void string_concat(char **pzStr, char *zAppend, int doFree, int *pRc){
static int echoBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
int ii;
char *zQuery = 0;
char *zCol = 0;
char *zNew;
int nArg = 0;
const char *zSep = "WHERE";
@@ -817,10 +846,11 @@ static int echoBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
}
}
zQuery = sqlite3_mprintf("SELECT rowid, * FROM %Q", pVtab->zTableName);
if( !zQuery ){
return SQLITE_NOMEM;
}
zCol = echoSelectList(pVtab, pIdxInfo);
if( !zCol ) return SQLITE_NOMEM;
zQuery = sqlite3_mprintf("SELECT rowid%z FROM %Q", zCol, pVtab->zTableName);
if( !zQuery ) return SQLITE_NOMEM;
for(ii=0; ii<pIdxInfo->nConstraint; ii++){
const struct sqlite3_index_constraint *pConstraint;
struct sqlite3_index_constraint_usage *pUsage;