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Enhance the DBSTAT virtual table with a new hidden table "schema" that if

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set will cause the table to report on the specified schema rather than on
"main".  Also:  Fix a faulty assert in sqlite3_context_db_handle().

FossilOrigin-Name: 6beb512c7a3c3649b56f0df1ca77855535a87ba7
This commit is contained in:
drh
2015-09-08 21:12:53 +00:00
parent b4d472f609
commit a46a4a63de
4 changed files with 86 additions and 37 deletions
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105
src/dbstat.c
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@@ -16,6 +16,9 @@
** information from an SQLite database in order to implement the
** "sqlite3_analyzer" utility. See the ../tool/spaceanal.tcl script
** for an example implementation.
**
** Additional information is available on the "dbstat.html" page of the
** official SQLite documentation.
*/
#include "sqliteInt.h" /* Requires access to internal data structures */
@@ -64,7 +67,8 @@
" unused INTEGER, /* Bytes of unused space on this page */" \
" mx_payload INTEGER, /* Largest payload size of all cells */" \
" pgoffset INTEGER, /* Offset of page in file */" \
" pgsize INTEGER /* Size of the page */" \
" pgsize INTEGER, /* Size of the page */" \
" schema TEXT HIDDEN /* Database schema being analyzed */" \
");"
@@ -102,6 +106,7 @@ struct StatCursor {
sqlite3_vtab_cursor base;
sqlite3_stmt *pStmt; /* Iterates through set of root pages */
int isEof; /* After pStmt has returned SQLITE_DONE */
int iDb; /* Schema used for this query */
StatPage aPage[32];
int iPage; /* Current entry in aPage[] */
@@ -179,9 +184,32 @@ static int statDisconnect(sqlite3_vtab *pVtab){
/*
** There is no "best-index". This virtual table always does a linear
** scan of the binary VFS log file.
** scan. However, a schema=? constraint should cause this table to
** operate on a different database schema, so check for it.
**
** idxNum is normally 0, but will be 1 if a schema=? constraint exists.
*/
static int statBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
int i;
pIdxInfo->estimatedCost = 1.0e6; /* Initial cost estimate */
/* Look for a valid schema=? constraint. If found, change the idxNum to
** 1 and request the value of that constraint be sent to xFilter. And
** lower the cost estimate to encourage the constrained version to be
** used.
*/
for(i=0; i<pIdxInfo->nConstraint; i++){
if( pIdxInfo->aConstraint[i].usable==0 ) continue;
if( pIdxInfo->aConstraint[i].op!=SQLITE_INDEX_CONSTRAINT_EQ ) continue;
if( pIdxInfo->aConstraint[i].iColumn!=10 ) continue;
pIdxInfo->idxNum = 1;
pIdxInfo->estimatedCost = 1.0;
pIdxInfo->aConstraintUsage[i].argvIndex = 1;
pIdxInfo->aConstraintUsage[i].omit = 1;
break;
}
/* Records are always returned in ascending order of (name, path).
** If this will satisfy the client, set the orderByConsumed flag so that
@@ -201,7 +229,6 @@ static int statBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
pIdxInfo->orderByConsumed = 1;
}
pIdxInfo->estimatedCost = 10.0;
return SQLITE_OK;
}
@@ -211,36 +238,18 @@ static int statBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
static int statOpen(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor){
StatTable *pTab = (StatTable *)pVTab;
StatCursor *pCsr;
int rc;
pCsr = (StatCursor *)sqlite3_malloc64(sizeof(StatCursor));
if( pCsr==0 ){
rc = SQLITE_NOMEM;
return SQLITE_NOMEM;
}else{
char *zSql;
memset(pCsr, 0, sizeof(StatCursor));
pCsr->base.pVtab = pVTab;
zSql = sqlite3_mprintf(
"SELECT 'sqlite_master' AS name, 1 AS rootpage, 'table' AS type"
" UNION ALL "
"SELECT name, rootpage, type"
" FROM \"%w\".sqlite_master WHERE rootpage!=0"
" ORDER BY name", pTab->db->aDb[pTab->iDb].zName);
if( zSql==0 ){
rc = SQLITE_NOMEM;
}else{
rc = sqlite3_prepare_v2(pTab->db, zSql, -1, &pCsr->pStmt, 0);
sqlite3_free(zSql);
}
if( rc!=SQLITE_OK ){
sqlite3_free(pCsr);
pCsr = 0;
}
pCsr->iDb = pTab->iDb;
}
*ppCursor = (sqlite3_vtab_cursor *)pCsr;
return rc;
return SQLITE_OK;
}
static void statClearPage(StatPage *p){
@@ -265,6 +274,7 @@ static void statResetCsr(StatCursor *pCsr){
pCsr->iPage = 0;
sqlite3_free(pCsr->zPath);
pCsr->zPath = 0;
pCsr->isEof = 0;
}
/*
@@ -427,7 +437,7 @@ static int statNext(sqlite3_vtab_cursor *pCursor){
char *z;
StatCursor *pCsr = (StatCursor *)pCursor;
StatTable *pTab = (StatTable *)pCursor->pVtab;
Btree *pBt = pTab->db->aDb[pTab->iDb].pBt;
Btree *pBt = pTab->db->aDb[pCsr->iDb].pBt;
Pager *pPager = sqlite3BtreePager(pBt);
sqlite3_free(pCsr->zPath);
@@ -565,9 +575,43 @@ static int statFilter(
int argc, sqlite3_value **argv
){
StatCursor *pCsr = (StatCursor *)pCursor;
StatTable *pTab = (StatTable*)(pCursor->pVtab);
char *zSql;
int rc = SQLITE_OK;
char *zMaster;
if( idxNum==1 ){
const char *zDbase = (const char*)sqlite3_value_text(argv[0]);
pCsr->iDb = sqlite3FindDbName(pTab->db, zDbase);
if( pCsr->iDb<0 ){
sqlite3_free(pCursor->pVtab->zErrMsg);
pCursor->pVtab->zErrMsg = sqlite3_mprintf("no such schema: %s", zDbase);
return pCursor->pVtab->zErrMsg ? SQLITE_ERROR : SQLITE_NOMEM;
}
}else{
pCsr->iDb = pTab->iDb;
}
statResetCsr(pCsr);
return statNext(pCursor);
sqlite3_finalize(pCsr->pStmt);
pCsr->pStmt = 0;
zMaster = pCsr->iDb==1 ? "sqlite_temp_master" : "sqlite_master";
zSql = sqlite3_mprintf(
"SELECT 'sqlite_master' AS name, 1 AS rootpage, 'table' AS type"
" UNION ALL "
"SELECT name, rootpage, type"
" FROM \"%w\".%s WHERE rootpage!=0"
" ORDER BY name", pTab->db->aDb[pCsr->iDb].zName, zMaster);
if( zSql==0 ){
return SQLITE_NOMEM;
}else{
rc = sqlite3_prepare_v2(pTab->db, zSql, -1, &pCsr->pStmt, 0);
sqlite3_free(zSql);
}
if( rc==SQLITE_OK ){
rc = statNext(pCursor);
}
return rc;
}
static int statColumn(
@@ -604,10 +648,15 @@ static int statColumn(
case 8: /* pgoffset */
sqlite3_result_int64(ctx, pCsr->iOffset);
break;
default: /* pgsize */
assert( i==9 );
case 9: /* pgsize */
sqlite3_result_int(ctx, pCsr->szPage);
break;
default: { /* schema */
sqlite3 *db = sqlite3_context_db_handle(ctx);
int iDb = pCsr->iDb;
sqlite3_result_text(ctx, db->aDb[iDb].zName, -1, SQLITE_STATIC);
break;
}
}
return SQLITE_OK;
}