--- /dev/null
-
+/*
+** 2017 April 09
+**
+** The author disclaims copyright to this source code. In place of
+** a legal notice, here is a blessing:
+**
+** May you do good and not evil.
+** May you find forgiveness for yourself and forgive others.
+** May you share freely, never taking more than you give.
+**
+*************************************************************************
+*/
+
+#if !defined(SQLITE_TEST) || defined(SQLITE_ENABLE_WHEREINFO_HOOK)
+
+#include "sqlite3expert.h"
+#include <assert.h>
+#include <string.h>
+#include <stdio.h>
+
+typedef sqlite3_int64 i64;
+typedef sqlite3_uint64 u64;
+
+typedef struct IdxColumn IdxColumn;
+typedef struct IdxConstraint IdxConstraint;
+typedef struct IdxScan IdxScan;
+typedef struct IdxStatement IdxStatement;
+typedef struct IdxTable IdxTable;
+typedef struct IdxWrite IdxWrite;
+
++/*
++** A temp table name that we assume no user database will actually use.
++** If this assumption proves incorrect triggers on the table with the
++** conflicting name will be ignored.
++*/
+#define UNIQUE_TABLE_NAME "t592690916721053953805701627921227776"
+
+/*
+** A single constraint. Equivalent to either "col = ?" or "col < ?" (or
+** any other type of single-ended range constraint on a column).
+**
+** pLink:
+** Used to temporarily link IdxConstraint objects into lists while
+** creating candidate indexes.
+*/
+struct IdxConstraint {
+ char *zColl; /* Collation sequence */
+ int bRange; /* True for range, false for eq */
+ int iCol; /* Constrained table column */
+ int bFlag; /* Used by idxFindCompatible() */
+ int bDesc; /* True if ORDER BY <expr> DESC */
+ IdxConstraint *pNext; /* Next constraint in pEq or pRange list */
+ IdxConstraint *pLink; /* See above */
+};
+
+/*
+** A single scan of a single table.
+*/
+struct IdxScan {
+ IdxTable *pTab; /* Associated table object */
+ int iDb; /* Database containing table zTable */
+ i64 covering; /* Mask of columns required for cov. index */
+ IdxConstraint *pOrder; /* ORDER BY columns */
+ IdxConstraint *pEq; /* List of == constraints */
+ IdxConstraint *pRange; /* List of < constraints */
+ IdxScan *pNextScan; /* Next IdxScan object for same analysis */
+};
+
+/*
+** Information regarding a single database table. Extracted from
+** "PRAGMA table_info" by function idxGetTableInfo().
+*/
+struct IdxColumn {
+ char *zName;
+ char *zColl;
+ int iPk;
+};
+struct IdxTable {
+ int nCol;
+ char *zName; /* Table name */
+ IdxColumn *aCol;
+ IdxTable *pNext; /* Next table in linked list of all tables */
+};
+
+/*
+** An object of the following type is created for each unique table/write-op
+** seen. The objects are stored in a singly-linked list beginning at
+** sqlite3expert.pWrite.
+*/
+struct IdxWrite {
+ IdxTable *pTab;
+ int eOp; /* SQLITE_UPDATE, DELETE or INSERT */
+ IdxWrite *pNext;
+};
+
+/*
+** Each statement being analyzed is represented by an instance of this
+** structure.
+*/
+struct IdxStatement {
+ int iId; /* Statement number */
+ char *zSql; /* SQL statement */
+ char *zIdx; /* Indexes */
+ char *zEQP; /* Plan */
+ IdxStatement *pNext;
+};
+
+
+/*
+** A hash table for storing strings. With space for a payload string
+** with each entry. Methods are:
+**
+** idxHashInit()
+** idxHashClear()
+** idxHashAdd()
+** idxHashSearch()
+*/
+#define IDX_HASH_SIZE 1023
+typedef struct IdxHashEntry IdxHashEntry;
+typedef struct IdxHash IdxHash;
+struct IdxHashEntry {
+ char *zKey; /* nul-terminated key */
+ char *zVal; /* nul-terminated value string */
+ char *zVal2; /* nul-terminated value string 2 */
+ IdxHashEntry *pHashNext; /* Next entry in same hash bucket */
+ IdxHashEntry *pNext; /* Next entry in hash */
+};
+struct IdxHash {
+ IdxHashEntry *pFirst;
+ IdxHashEntry *aHash[IDX_HASH_SIZE];
+};
+
+/*
+** sqlite3expert object.
+*/
+struct sqlite3expert {
+ int iSample; /* Percentage of tables to sample for stat1 */
+ sqlite3 *db; /* User database */
+ sqlite3 *dbm; /* In-memory db for this analysis */
+ sqlite3 *dbv; /* Vtab schema for this analysis */
+ IdxTable *pTable; /* List of all IdxTable objects */
+ IdxScan *pScan; /* List of scan objects */
+ IdxWrite *pWrite; /* List of write objects */
+ IdxStatement *pStatement; /* List of IdxStatement objects */
+ int bRun; /* True once analysis has run */
+ char **pzErrmsg;
+ int rc; /* Error code from whereinfo hook */
+ IdxHash hIdx; /* Hash containing all candidate indexes */
+ char *zCandidates; /* For EXPERT_REPORT_CANDIDATES */
+};
+
+
+/*
+** Allocate and return nByte bytes of zeroed memory using sqlite3_malloc().
+** If the allocation fails, set *pRc to SQLITE_NOMEM and return NULL.
+*/
+static void *idxMalloc(int *pRc, int nByte){
+ void *pRet;
+ assert( *pRc==SQLITE_OK );
+ assert( nByte>0 );
+ pRet = sqlite3_malloc(nByte);
+ if( pRet ){
+ memset(pRet, 0, nByte);
+ }else{
+ *pRc = SQLITE_NOMEM;
+ }
+ return pRet;
+}
+
+/*
+** Initialize an IdxHash hash table.
+*/
+static void idxHashInit(IdxHash *pHash){
+ memset(pHash, 0, sizeof(IdxHash));
+}
+
+/*
+** Reset an IdxHash hash table.
+*/
+static void idxHashClear(IdxHash *pHash){
+ int i;
+ for(i=0; i<IDX_HASH_SIZE; i++){
+ IdxHashEntry *pEntry;
+ IdxHashEntry *pNext;
+ for(pEntry=pHash->aHash[i]; pEntry; pEntry=pNext){
+ pNext = pEntry->pHashNext;
+ sqlite3_free(pEntry->zVal2);
+ sqlite3_free(pEntry);
+ }
+ }
+ memset(pHash, 0, sizeof(IdxHash));
+}
+
+/*
+** Return the index of the hash bucket that the string specified by the
+** arguments to this function belongs.
+*/
+static int idxHashString(const char *z, int n){
+ unsigned int ret = 0;
+ int i;
+ for(i=0; i<n; i++){
+ ret += (ret<<3) + (unsigned char)(z[i]);
+ }
+ return (int)(ret % IDX_HASH_SIZE);
+}
+
+/*
+** If zKey is already present in the hash table, return non-zero and do
+** nothing. Otherwise, add an entry with key zKey and payload string zVal to
+** the hash table passed as the second argument.
+*/
+static int idxHashAdd(
+ int *pRc,
+ IdxHash *pHash,
+ const char *zKey,
+ const char *zVal
+){
+ int nKey = strlen(zKey);
+ int iHash = idxHashString(zKey, nKey);
+ int nVal = (zVal ? strlen(zVal) : 0);
+ IdxHashEntry *pEntry;
+ assert( iHash>=0 );
+ for(pEntry=pHash->aHash[iHash]; pEntry; pEntry=pEntry->pHashNext){
+ if( strlen(pEntry->zKey)==nKey && 0==memcmp(pEntry->zKey, zKey, nKey) ){
+ return 1;
+ }
+ }
+ pEntry = idxMalloc(pRc, sizeof(IdxHashEntry) + nKey+1 + nVal+1);
+ if( pEntry ){
+ pEntry->zKey = (char*)&pEntry[1];
+ memcpy(pEntry->zKey, zKey, nKey);
+ if( zVal ){
+ pEntry->zVal = &pEntry->zKey[nKey+1];
+ memcpy(pEntry->zVal, zVal, nVal);
+ }
+ pEntry->pHashNext = pHash->aHash[iHash];
+ pHash->aHash[iHash] = pEntry;
+
+ pEntry->pNext = pHash->pFirst;
+ pHash->pFirst = pEntry;
+ }
+ return 0;
+}
+
++/*
++** If zKey/nKey is present in the hash table, return a pointer to the
++** hash-entry object.
++*/
+static IdxHashEntry *idxHashFind(IdxHash *pHash, const char *zKey, int nKey){
+ int iHash;
+ IdxHashEntry *pEntry;
+ if( nKey<0 ) nKey = strlen(zKey);
+ iHash = idxHashString(zKey, nKey);
+ assert( iHash>=0 );
+ for(pEntry=pHash->aHash[iHash]; pEntry; pEntry=pEntry->pHashNext){
+ if( strlen(pEntry->zKey)==nKey && 0==memcmp(pEntry->zKey, zKey, nKey) ){
+ return pEntry;
+ }
+ }
+ return 0;
+}
+
+/*
+** If the hash table contains an entry with a key equal to the string
+** passed as the final two arguments to this function, return a pointer
+** to the payload string. Otherwise, if zKey/nKey is not present in the
+** hash table, return NULL.
+*/
+static const char *idxHashSearch(IdxHash *pHash, const char *zKey, int nKey){
+ IdxHashEntry *pEntry = idxHashFind(pHash, zKey, nKey);
+ if( pEntry ) return pEntry->zVal;
+ return 0;
+}
+
+/*
+** Allocate and return a new IdxConstraint object. Set the IdxConstraint.zColl
+** variable to point to a copy of nul-terminated string zColl.
+*/
+static IdxConstraint *idxNewConstraint(int *pRc, const char *zColl){
+ IdxConstraint *pNew;
+ int nColl = strlen(zColl);
+
+ assert( *pRc==SQLITE_OK );
+ pNew = (IdxConstraint*)idxMalloc(pRc, sizeof(IdxConstraint) * nColl + 1);
+ if( pNew ){
+ pNew->zColl = (char*)&pNew[1];
+ memcpy(pNew->zColl, zColl, nColl+1);
+ }
+ return pNew;
+}
+
+/*
+** An error associated with database handle db has just occurred. Pass
+** the error message to callback function xOut.
+*/
+static void idxDatabaseError(
+ sqlite3 *db, /* Database handle */
+ char **pzErrmsg /* Write error here */
+){
+ *pzErrmsg = sqlite3_mprintf("%s", sqlite3_errmsg(db));
+}
+
+/*
+** Prepare an SQL statement.
+*/
+static int idxPrepareStmt(
+ sqlite3 *db, /* Database handle to compile against */
+ sqlite3_stmt **ppStmt, /* OUT: Compiled SQL statement */
+ char **pzErrmsg, /* OUT: sqlite3_malloc()ed error message */
+ const char *zSql /* SQL statement to compile */
+){
+ int rc = sqlite3_prepare_v2(db, zSql, -1, ppStmt, 0);
+ if( rc!=SQLITE_OK ){
+ *ppStmt = 0;
+ idxDatabaseError(db, pzErrmsg);
+ }
+ return rc;
+}
+
+/*
+** Prepare an SQL statement using the results of a printf() formatting.
+*/
+static int idxPrintfPrepareStmt(
+ sqlite3 *db, /* Database handle to compile against */
+ sqlite3_stmt **ppStmt, /* OUT: Compiled SQL statement */
+ char **pzErrmsg, /* OUT: sqlite3_malloc()ed error message */
+ const char *zFmt, /* printf() format of SQL statement */
+ ... /* Trailing printf() arguments */
+){
+ va_list ap;
+ int rc;
+ char *zSql;
+ va_start(ap, zFmt);
+ zSql = sqlite3_vmprintf(zFmt, ap);
+ if( zSql==0 ){
+ rc = SQLITE_NOMEM;
+ }else{
+ rc = idxPrepareStmt(db, ppStmt, pzErrmsg, zSql);
+ sqlite3_free(zSql);
+ }
+ va_end(ap);
+ return rc;
+}
+
+
+/*************************************************************************
+** Beginning of virtual table implementation.
+*/
+typedef struct ExpertVtab ExpertVtab;
+struct ExpertVtab {
+ sqlite3_vtab base;
+ IdxTable *pTab;
+ sqlite3expert *pExpert;
+};
+
+typedef struct ExpertCsr ExpertCsr;
+struct ExpertCsr {
+ sqlite3_vtab_cursor base;
+ sqlite3_stmt *pData;
+};
+
+static char *expertDequote(const char *zIn){
+ int n = strlen(zIn);
+ char *zRet = sqlite3_malloc(n);
+
+ assert( zIn[0]=='\'' );
+ assert( zIn[n-1]=='\'' );
+
+ if( zRet ){
+ int iOut = 0;
+ int iIn = 0;
+ for(iIn=1; iIn<(n-1); iIn++){
+ if( zIn[iIn]=='\'' ){
+ assert( zIn[iIn+1]=='\'' );
+ iIn++;
+ }
+ zRet[iOut++] = zIn[iIn];
+ }
+ zRet[iOut] = '\0';
+ }
+
+ return zRet;
+}
+
+/*
+** This function is the implementation of both the xConnect and xCreate
+** methods of the r-tree virtual table.
+**
+** argv[0] -> module name
+** argv[1] -> database name
+** argv[2] -> table name
+** argv[...] -> column names...
+*/
+static int expertConnect(
+ sqlite3 *db,
+ void *pAux,
+ int argc, const char *const*argv,
+ sqlite3_vtab **ppVtab,
+ char **pzErr
+){
+ sqlite3expert *pExpert = (sqlite3expert*)pAux;
+ ExpertVtab *p = 0;
+ int rc;
+
+ if( argc!=4 ){
+ *pzErr = sqlite3_mprintf("internal error!");
+ rc = SQLITE_ERROR;
+ }else{
+ char *zCreateTable = expertDequote(argv[3]);
+ if( zCreateTable ){
+ rc = sqlite3_declare_vtab(db, zCreateTable);
+ if( rc==SQLITE_OK ){
+ p = idxMalloc(&rc, sizeof(ExpertVtab));
+ }
+ if( rc==SQLITE_OK ){
+ p->pExpert = pExpert;
+ p->pTab = pExpert->pTable;
+ assert( sqlite3_stricmp(p->pTab->zName, argv[2])==0 );
+ }
+ sqlite3_free(zCreateTable);
+ }else{
+ rc = SQLITE_NOMEM;
+ }
+ }
+
+ *ppVtab = (sqlite3_vtab*)p;
+ return rc;
+}
+
+static int expertDisconnect(sqlite3_vtab *pVtab){
+ ExpertVtab *p = (ExpertVtab*)pVtab;
+ sqlite3_free(p);
+ return SQLITE_OK;
+}
+
+static int expertBestIndex(sqlite3_vtab *pVtab, sqlite3_index_info *pIdxInfo){
+ ExpertVtab *p = (ExpertVtab*)pVtab;
+ sqlite3 *dbv = p->pExpert->dbv;
+ int rc = SQLITE_OK;
+ int n = 0;
+ IdxScan *pScan;
+ const int opmask =
+ SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_GT |
+ SQLITE_INDEX_CONSTRAINT_LT | SQLITE_INDEX_CONSTRAINT_GE |
+ SQLITE_INDEX_CONSTRAINT_LE;
+
+ pScan = idxMalloc(&rc, sizeof(IdxScan));
+ if( pScan ){
+ int i;
+
+ /* Link the new scan object into the list */
+ pScan->pTab = p->pTab;
+ pScan->pNextScan = p->pExpert->pScan;
+ p->pExpert->pScan = pScan;
+
+ /* Add the constraints to the IdxScan object */
+ for(i=0; i<pIdxInfo->nConstraint; i++){
+ struct sqlite3_index_constraint *pCons = &pIdxInfo->aConstraint[i];
+ if( pCons->usable
+ && pCons->iColumn>=0
+ && p->pTab->aCol[pCons->iColumn].iPk==0
+ && (pCons->op & opmask)
+ ){
+ IdxConstraint *pNew;
+ const char *zColl = sqlite3_vtab_collation(dbv, i);
+ pNew = idxNewConstraint(&rc, zColl);
+ if( pNew ){
+ pNew->iCol = pCons->iColumn;
+ if( pCons->op==SQLITE_INDEX_CONSTRAINT_EQ ){
+ pNew->pNext = pScan->pEq;
+ pScan->pEq = pNew;
+ }else{
+ pNew->bRange = 1;
+ pNew->pNext = pScan->pRange;
+ pScan->pRange = pNew;
+ }
+ }
+ n++;
+ pIdxInfo->aConstraintUsage[i].argvIndex = n;
+ }
+ }
+
+ /* Add the ORDER BY to the IdxScan object */
+ for(i=pIdxInfo->nOrderBy-1; i>=0; i--){
+ int iCol = pIdxInfo->aOrderBy[i].iColumn;
+ if( iCol>=0 ){
+ IdxConstraint *pNew = idxNewConstraint(&rc, p->pTab->aCol[iCol].zColl);
+ if( pNew ){
+ pNew->iCol = iCol;
+ pNew->bDesc = pIdxInfo->aOrderBy[i].desc;
+ pNew->pNext = pScan->pOrder;
+ pNew->pLink = pScan->pOrder;
+ pScan->pOrder = pNew;
+ n++;
+ }
+ }
+ }
+ }
+
+ pIdxInfo->estimatedCost = 1000000.0 / n;
+ return rc;
+}
+
+static int expertUpdate(
+ sqlite3_vtab *pVtab,
+ int nData,
+ sqlite3_value **azData,
+ sqlite_int64 *pRowid
+){
+ return SQLITE_OK;
+}
+
+/*
+** Virtual table module xOpen method.
+*/
+static int expertOpen(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor){
+ int rc = SQLITE_OK;
+ ExpertCsr *pCsr;
+ pCsr = idxMalloc(&rc, sizeof(ExpertCsr));
+ *ppCursor = (sqlite3_vtab_cursor*)pCsr;
+ return rc;
+}
+
+/*
+** Virtual table module xClose method.
+*/
+static int expertClose(sqlite3_vtab_cursor *cur){
+ ExpertCsr *pCsr = (ExpertCsr*)cur;
+ sqlite3_finalize(pCsr->pData);
+ sqlite3_free(pCsr);
+ return SQLITE_OK;
+}
+
+/*
+** Virtual table module xEof method.
+**
+** Return non-zero if the cursor does not currently point to a valid
+** record (i.e if the scan has finished), or zero otherwise.
+*/
+static int expertEof(sqlite3_vtab_cursor *cur){
+ ExpertCsr *pCsr = (ExpertCsr*)cur;
+ return pCsr->pData==0;
+}
+
+/*
+** Virtual table module xNext method.
+*/
+static int expertNext(sqlite3_vtab_cursor *cur){
+ ExpertCsr *pCsr = (ExpertCsr*)cur;
+ int rc = SQLITE_OK;
+
+ assert( pCsr->pData );
+ rc = sqlite3_step(pCsr->pData);
+ if( rc!=SQLITE_ROW ){
+ rc = sqlite3_finalize(pCsr->pData);
+ pCsr->pData = 0;
+ }else{
+ rc = SQLITE_OK;
+ }
+
+ return rc;
+}
+
+/*
+** Virtual table module xRowid method.
+*/
+static int expertRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){
+ *pRowid = 0;
+ return SQLITE_OK;
+}
+
+/*
+** Virtual table module xColumn method.
+*/
+static int expertColumn(sqlite3_vtab_cursor *cur, sqlite3_context *ctx, int i){
+ ExpertCsr *pCsr = (ExpertCsr*)cur;
+ sqlite3_value *pVal;
+ pVal = sqlite3_column_value(pCsr->pData, i);
+ if( pVal ){
+ sqlite3_result_value(ctx, pVal);
+ }
+ return SQLITE_OK;
+}
+
+/*
+** Virtual table module xFilter method.
+*/
+static int expertFilter(
+ sqlite3_vtab_cursor *cur,
+ int idxNum, const char *idxStr,
+ int argc, sqlite3_value **argv
+){
+ ExpertCsr *pCsr = (ExpertCsr*)cur;
+ ExpertVtab *pVtab = (ExpertVtab*)(cur->pVtab);
+ sqlite3expert *pExpert = pVtab->pExpert;
+ int rc;
+
+ rc = sqlite3_finalize(pCsr->pData);
+ pCsr->pData = 0;
+ if( rc==SQLITE_OK ){
+ rc = idxPrintfPrepareStmt(pExpert->db, &pCsr->pData, &pVtab->base.zErrMsg,
+ "SELECT * FROM main.%Q WHERE sample()", pVtab->pTab->zName
+ );
+ }
+
+ if( rc==SQLITE_OK ){
+ rc = expertNext(cur);
+ }
+ return rc;
+}
+
+static int idxRegisterVtab(sqlite3expert *p){
+ static sqlite3_module expertModule = {
+ 2, /* iVersion */
+ expertConnect, /* xCreate - create a table */
+ expertConnect, /* xConnect - connect to an existing table */
+ expertBestIndex, /* xBestIndex - Determine search strategy */
+ expertDisconnect, /* xDisconnect - Disconnect from a table */
+ expertDisconnect, /* xDestroy - Drop a table */
+ expertOpen, /* xOpen - open a cursor */
+ expertClose, /* xClose - close a cursor */
+ expertFilter, /* xFilter - configure scan constraints */
+ expertNext, /* xNext - advance a cursor */
+ expertEof, /* xEof */
+ expertColumn, /* xColumn - read data */
+ expertRowid, /* xRowid - read data */
+ expertUpdate, /* xUpdate - write data */
+ 0, /* xBegin - begin transaction */
+ 0, /* xSync - sync transaction */
+ 0, /* xCommit - commit transaction */
+ 0, /* xRollback - rollback transaction */
+ 0, /* xFindFunction - function overloading */
+ 0, /* xRename - rename the table */
+ 0, /* xSavepoint */
+ 0, /* xRelease */
+ 0, /* xRollbackTo */
+ };
+
+ return sqlite3_create_module(p->dbv, "expert", &expertModule, (void*)p);
+}
+/*
+** End of virtual table implementation.
+*************************************************************************/
+/*
+** Finalize SQL statement pStmt. If (*pRc) is SQLITE_OK when this function
+** is called, set it to the return value of sqlite3_finalize() before
+** returning. Otherwise, discard the sqlite3_finalize() return value.
+*/
+static void idxFinalize(int *pRc, sqlite3_stmt *pStmt){
+ int rc = sqlite3_finalize(pStmt);
+ if( *pRc==SQLITE_OK ) *pRc = rc;
+}
+
+/*
+** Attempt to allocate an IdxTable structure corresponding to table zTab
+** in the main database of connection db. If successful, set (*ppOut) to
+** point to the new object and return SQLITE_OK. Otherwise, return an
+** SQLite error code and set (*ppOut) to NULL. In this case *pzErrmsg may be
+** set to point to an error string.
+**
+** It is the responsibility of the caller to eventually free either the
+** IdxTable object or error message using sqlite3_free().
+*/
+static int idxGetTableInfo(
+ sqlite3 *db, /* Database connection to read details from */
+ const char *zTab, /* Table name */
+ IdxTable **ppOut, /* OUT: New object (if successful) */
+ char **pzErrmsg /* OUT: Error message (if not) */
+){
+ sqlite3_stmt *p1 = 0;
+ int nCol = 0;
+ int nTab = strlen(zTab);
+ int nByte = sizeof(IdxTable) + nTab + 1;
+ IdxTable *pNew = 0;
+ int rc, rc2;
+ char *pCsr = 0;
+
+ rc = idxPrintfPrepareStmt(db, &p1, pzErrmsg, "PRAGMA table_info=%Q", zTab);
+ while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(p1) ){
+ const char *zCol = (const char*)sqlite3_column_text(p1, 1);
+ nByte += 1 + strlen(zCol);
+ rc = sqlite3_table_column_metadata(
+ db, "main", zTab, zCol, 0, &zCol, 0, 0, 0
+ );
+ nByte += 1 + strlen(zCol);
+ nCol++;
+ }
+ rc2 = sqlite3_reset(p1);
+ if( rc==SQLITE_OK ) rc = rc2;
+
+ nByte += sizeof(IdxColumn) * nCol;
+ if( rc==SQLITE_OK ){
+ pNew = idxMalloc(&rc, nByte);
+ }
+ if( rc==SQLITE_OK ){
+ pNew->aCol = (IdxColumn*)&pNew[1];
+ pNew->nCol = nCol;
+ pCsr = (char*)&pNew->aCol[nCol];
+ }
+
+ nCol = 0;
+ while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(p1) ){
+ const char *zCol = (const char*)sqlite3_column_text(p1, 1);
+ int nCopy = strlen(zCol) + 1;
+ pNew->aCol[nCol].zName = pCsr;
+ pNew->aCol[nCol].iPk = sqlite3_column_int(p1, 5);
+ memcpy(pCsr, zCol, nCopy);
+ pCsr += nCopy;
+
+ rc = sqlite3_table_column_metadata(
+ db, "main", zTab, zCol, 0, &zCol, 0, 0, 0
+ );
+ if( rc==SQLITE_OK ){
+ nCopy = strlen(zCol) + 1;
+ pNew->aCol[nCol].zColl = pCsr;
+ memcpy(pCsr, zCol, nCopy);
+ pCsr += nCopy;
+ }
+
+ nCol++;
+ }
+ idxFinalize(&rc, p1);
+
+ if( rc!=SQLITE_OK ){
+ sqlite3_free(pNew);
+ pNew = 0;
+ }else{
+ pNew->zName = pCsr;
+ memcpy(pNew->zName, zTab, nTab+1);
+ }
+
+ *ppOut = pNew;
+ return rc;
+}
+
+/*
+** This function is a no-op if *pRc is set to anything other than
+** SQLITE_OK when it is called.
+**
+** If *pRc is initially set to SQLITE_OK, then the text specified by
+** the printf() style arguments is appended to zIn and the result returned
+** in a buffer allocated by sqlite3_malloc(). sqlite3_free() is called on
+** zIn before returning.
+*/
+static char *idxAppendText(int *pRc, char *zIn, const char *zFmt, ...){
+ va_list ap;
+ char *zAppend = 0;
+ char *zRet = 0;
+ int nIn = zIn ? strlen(zIn) : 0;
+ int nAppend = 0;
+ va_start(ap, zFmt);
+ if( *pRc==SQLITE_OK ){
+ zAppend = sqlite3_vmprintf(zFmt, ap);
+ if( zAppend ){
+ nAppend = strlen(zAppend);
+ zRet = (char*)sqlite3_malloc(nIn + nAppend + 1);
+ }
+ if( zAppend && zRet ){
+ memcpy(zRet, zIn, nIn);
+ memcpy(&zRet[nIn], zAppend, nAppend+1);
+ }else{
+ sqlite3_free(zRet);
+ zRet = 0;
+ *pRc = SQLITE_NOMEM;
+ }
+ sqlite3_free(zAppend);
+ sqlite3_free(zIn);
+ }
+ va_end(ap);
+ return zRet;
+}
+
+/*
+** Return true if zId must be quoted in order to use it as an SQL
+** identifier, or false otherwise.
+*/
+static int idxIdentifierRequiresQuotes(const char *zId){
+ int i;
+ for(i=0; zId[i]; i++){
+ if( !(zId[i]=='_')
+ && !(zId[i]>='0' && zId[i]<='9')
+ && !(zId[i]>='a' && zId[i]<='z')
+ && !(zId[i]>='A' && zId[i]<='Z')
+ ){
+ return 1;
+ }
+ }
+ return 0;
+}
+
+/*
+** This function appends an index column definition suitable for constraint
+** pCons to the string passed as zIn and returns the result.
+*/
+static char *idxAppendColDefn(
+ int *pRc, /* IN/OUT: Error code */
+ char *zIn, /* Column defn accumulated so far */
+ IdxTable *pTab, /* Table index will be created on */
+ IdxConstraint *pCons
+){
+ char *zRet = zIn;
+ IdxColumn *p = &pTab->aCol[pCons->iCol];
+ if( zRet ) zRet = idxAppendText(pRc, zRet, ", ");
+
+ if( idxIdentifierRequiresQuotes(p->zName) ){
+ zRet = idxAppendText(pRc, zRet, "%Q", p->zName);
+ }else{
+ zRet = idxAppendText(pRc, zRet, "%s", p->zName);
+ }
+
+ if( sqlite3_stricmp(p->zColl, pCons->zColl) ){
+ if( idxIdentifierRequiresQuotes(pCons->zColl) ){
+ zRet = idxAppendText(pRc, zRet, " COLLATE %Q", pCons->zColl);
+ }else{
+ zRet = idxAppendText(pRc, zRet, " COLLATE %s", pCons->zColl);
+ }
+ }
+
+ if( pCons->bDesc ){
+ zRet = idxAppendText(pRc, zRet, " DESC");
+ }
+ return zRet;
+}
+
+/*
+** Search database dbm for an index compatible with the one idxCreateFromCons()
+** would create from arguments pScan, pEq and pTail. If no error occurs and
+** such an index is found, return non-zero. Or, if no such index is found,
+** return zero.
+**
+** If an error occurs, set *pRc to an SQLite error code and return zero.
+*/
+static int idxFindCompatible(
+ int *pRc, /* OUT: Error code */
+ sqlite3* dbm, /* Database to search */
+ IdxScan *pScan, /* Scan for table to search for index on */
+ IdxConstraint *pEq, /* List of == constraints */
+ IdxConstraint *pTail /* List of range constraints */
+){
+ const char *zTbl = pScan->pTab->zName;
+ sqlite3_stmt *pIdxList = 0;
+ IdxConstraint *pIter;
+ int nEq = 0; /* Number of elements in pEq */
+ int rc;
+
+ /* Count the elements in list pEq */
+ for(pIter=pEq; pIter; pIter=pIter->pLink) nEq++;
+
+ rc = idxPrintfPrepareStmt(dbm, &pIdxList, 0, "PRAGMA index_list=%Q", zTbl);
+ while( rc==SQLITE_OK && sqlite3_step(pIdxList)==SQLITE_ROW ){
+ int bMatch = 1;
+ IdxConstraint *pT = pTail;
+ sqlite3_stmt *pInfo = 0;
+ const char *zIdx = (const char*)sqlite3_column_text(pIdxList, 1);
+
+ /* Zero the IdxConstraint.bFlag values in the pEq list */
+ for(pIter=pEq; pIter; pIter=pIter->pLink) pIter->bFlag = 0;
+
+ rc = idxPrintfPrepareStmt(dbm, &pInfo, 0, "PRAGMA index_xInfo=%Q", zIdx);
+ while( rc==SQLITE_OK && sqlite3_step(pInfo)==SQLITE_ROW ){
+ int iIdx = sqlite3_column_int(pInfo, 0);
+ int iCol = sqlite3_column_int(pInfo, 1);
+ const char *zColl = (const char*)sqlite3_column_text(pInfo, 4);
+
+ if( iIdx<nEq ){
+ for(pIter=pEq; pIter; pIter=pIter->pLink){
+ if( pIter->bFlag ) continue;
+ if( pIter->iCol!=iCol ) continue;
+ if( sqlite3_stricmp(pIter->zColl, zColl) ) continue;
+ pIter->bFlag = 1;
+ break;
+ }
+ if( pIter==0 ){
+ bMatch = 0;
+ break;
+ }
+ }else{
+ if( pT ){
+ if( pT->iCol!=iCol || sqlite3_stricmp(pT->zColl, zColl) ){
+ bMatch = 0;
+ break;
+ }
+ pT = pT->pLink;
+ }
+ }
+ }
+ idxFinalize(&rc, pInfo);
+
+ if( rc==SQLITE_OK && bMatch ){
+ sqlite3_finalize(pIdxList);
+ return 1;
+ }
+ }
+ idxFinalize(&rc, pIdxList);
+
+ *pRc = rc;
+ return 0;
+}
+
+static int idxCreateFromCons(
+ sqlite3expert *p,
+ IdxScan *pScan,
+ IdxConstraint *pEq,
+ IdxConstraint *pTail
+){
+ sqlite3 *dbm = p->dbm;
+ int rc = SQLITE_OK;
+ if( (pEq || pTail) && 0==idxFindCompatible(&rc, dbm, pScan, pEq, pTail) ){
+ IdxTable *pTab = pScan->pTab;
+ char *zCols = 0;
+ char *zIdx = 0;
+ IdxConstraint *pCons;
+ int h = 0;
+ const char *zFmt;
+
+ for(pCons=pEq; pCons; pCons=pCons->pLink){
+ zCols = idxAppendColDefn(&rc, zCols, pTab, pCons);
+ }
+ for(pCons=pTail; pCons; pCons=pCons->pLink){
+ zCols = idxAppendColDefn(&rc, zCols, pTab, pCons);
+ }
+
+ if( rc==SQLITE_OK ){
+ /* Hash the list of columns to come up with a name for the index */
+ const char *zTable = pScan->pTab->zName;
+ char *zName; /* Index name */
+ int i;
+ for(i=0; zCols[i]; i++){
+ h += ((h<<3) + zCols[i]);
+ }
+ zName = sqlite3_mprintf("%s_idx_%08x", zTable, h);
+ if( zName==0 ){
+ rc = SQLITE_NOMEM;
+ }else{
+ if( idxIdentifierRequiresQuotes(zTable) ){
+ zFmt = "CREATE INDEX '%q' ON %Q(%s)";
+ }else{
+ zFmt = "CREATE INDEX %s ON %s(%s)";
+ }
+ zIdx = sqlite3_mprintf(zFmt, zName, zTable, zCols);
+ if( !zIdx ){
+ rc = SQLITE_NOMEM;
+ }else{
+ rc = sqlite3_exec(dbm, zIdx, 0, 0, p->pzErrmsg);
+ idxHashAdd(&rc, &p->hIdx, zName, zIdx);
+ }
+ sqlite3_free(zName);
+ sqlite3_free(zIdx);
+ }
+ }
+
+ sqlite3_free(zCols);
+ }
+ return rc;
+}
+
+/*
+** Return true if list pList (linked by IdxConstraint.pLink) contains
+** a constraint compatible with *p. Otherwise return false.
+*/
+static int idxFindConstraint(IdxConstraint *pList, IdxConstraint *p){
+ IdxConstraint *pCmp;
+ for(pCmp=pList; pCmp; pCmp=pCmp->pLink){
+ if( p->iCol==pCmp->iCol ) return 1;
+ }
+ return 0;
+}
+
+static int idxCreateFromWhere(
+ sqlite3expert *p,
+ IdxScan *pScan, /* Create indexes for this scan */
+ IdxConstraint *pTail /* range/ORDER BY constraints for inclusion */
+){
+ IdxConstraint *p1 = 0;
+ IdxConstraint *pCon;
+ int rc;
+
+ /* Gather up all the == constraints. */
+ for(pCon=pScan->pEq; pCon; pCon=pCon->pNext){
+ if( !idxFindConstraint(p1, pCon) && !idxFindConstraint(pTail, pCon) ){
+ pCon->pLink = p1;
+ p1 = pCon;
+ }
+ }
+
+ /* Create an index using the == constraints collected above. And the
+ ** range constraint/ORDER BY terms passed in by the caller, if any. */
+ rc = idxCreateFromCons(p, pScan, p1, pTail);
+
+ /* If no range/ORDER BY passed by the caller, create a version of the
+ ** index for each range constraint. */
+ if( pTail==0 ){
+ for(pCon=pScan->pRange; rc==SQLITE_OK && pCon; pCon=pCon->pNext){
+ assert( pCon->pLink==0 );
+ if( !idxFindConstraint(p1, pCon) && !idxFindConstraint(pTail, pCon) ){
+ rc = idxCreateFromCons(p, pScan, p1, pCon);
+ }
+ }
+ }
+
+ return rc;
+}
+
+/*
+** Create candidate indexes in database [dbm] based on the data in
+** linked-list pScan.
+*/
+static int idxCreateCandidates(sqlite3expert *p, char **pzErr){
+ int rc = SQLITE_OK;
+ IdxScan *pIter;
+
+ for(pIter=p->pScan; pIter && rc==SQLITE_OK; pIter=pIter->pNextScan){
+ rc = idxCreateFromWhere(p, pIter, 0);
+ if( rc==SQLITE_OK && pIter->pOrder ){
+ rc = idxCreateFromWhere(p, pIter, pIter->pOrder);
+ }
+ }
+
+ return rc;
+}
+
+/*
+** Free all elements of the linked list starting at pConstraint.
+*/
+static void idxConstraintFree(IdxConstraint *pConstraint){
+ IdxConstraint *pNext;
+ IdxConstraint *p;
+
+ for(p=pConstraint; p; p=pNext){
+ pNext = p->pNext;
+ sqlite3_free(p);
+ }
+}
+
+/*
+** Free all elements of the linked list starting from pScan up until pLast
+** (pLast is not freed).
+*/
+static void idxScanFree(IdxScan *pScan, IdxScan *pLast){
+ IdxScan *p;
+ IdxScan *pNext;
+ for(p=pScan; p!=pLast; p=pNext){
+ pNext = p->pNextScan;
+ idxConstraintFree(p->pOrder);
+ idxConstraintFree(p->pEq);
+ idxConstraintFree(p->pRange);
+ sqlite3_free(p);
+ }
+}
+
+/*
+** Free all elements of the linked list starting from pStatement up
+** until pLast (pLast is not freed).
+*/
+static void idxStatementFree(IdxStatement *pStatement, IdxStatement *pLast){
+ IdxStatement *p;
+ IdxStatement *pNext;
+ for(p=pStatement; p!=pLast; p=pNext){
+ pNext = p->pNext;
+ sqlite3_free(p->zEQP);
+ sqlite3_free(p->zIdx);
+ sqlite3_free(p);
+ }
+}
+
+/*
+** Free the linked list of IdxTable objects starting at pTab.
+*/
+static void idxTableFree(IdxTable *pTab){
+ IdxTable *pIter;
+ IdxTable *pNext;
+ for(pIter=pTab; pIter; pIter=pNext){
+ pNext = pIter->pNext;
+ sqlite3_free(pIter);
+ }
+}
+
+/*
+** Free the linked list of IdxWrite objects starting at pTab.
+*/
+static void idxWriteFree(IdxWrite *pTab){
+ IdxWrite *pIter;
+ IdxWrite *pNext;
+ for(pIter=pTab; pIter; pIter=pNext){
+ pNext = pIter->pNext;
+ sqlite3_free(pIter);
+ }
+}
+
+
+
+/*
+** This function is called after candidate indexes have been created. It
+** runs all the queries to see which indexes they prefer, and populates
+** IdxStatement.zIdx and IdxStatement.zEQP with the results.
+*/
+int idxFindIndexes(
+ sqlite3expert *p,
+ char **pzErr /* OUT: Error message (sqlite3_malloc) */
+){
+ IdxStatement *pStmt;
+ sqlite3 *dbm = p->dbm;
+ int rc = SQLITE_OK;
+
+ IdxHash hIdx;
+ idxHashInit(&hIdx);
+
+ for(pStmt=p->pStatement; rc==SQLITE_OK && pStmt; pStmt=pStmt->pNext){
+ IdxHashEntry *pEntry;
+ sqlite3_stmt *pExplain = 0;
+ idxHashClear(&hIdx);
+ rc = idxPrintfPrepareStmt(dbm, &pExplain, pzErr,
+ "EXPLAIN QUERY PLAN %s", pStmt->zSql
+ );
+ while( rc==SQLITE_OK && sqlite3_step(pExplain)==SQLITE_ROW ){
+ int iSelectid = sqlite3_column_int(pExplain, 0);
+ int iOrder = sqlite3_column_int(pExplain, 1);
+ int iFrom = sqlite3_column_int(pExplain, 2);
+ const char *zDetail = (const char*)sqlite3_column_text(pExplain, 3);
+ int nDetail = strlen(zDetail);
+ int i;
+
+ for(i=0; i<nDetail; i++){
+ const char *zIdx = 0;
+ if( memcmp(&zDetail[i], " USING INDEX ", 13)==0 ){
+ zIdx = &zDetail[i+13];
+ }else if( memcmp(&zDetail[i], " USING COVERING INDEX ", 22)==0 ){
+ zIdx = &zDetail[i+22];
+ }
+ if( zIdx ){
+ const char *zSql;
+ int nIdx = 0;
+ while( zIdx[nIdx]!='\0' && (zIdx[nIdx]!=' ' || zIdx[nIdx+1]!='(') ){
+ nIdx++;
+ }
+ zSql = idxHashSearch(&p->hIdx, zIdx, nIdx);
+ if( zSql ){
+ idxHashAdd(&rc, &hIdx, zSql, 0);
+ if( rc ) goto find_indexes_out;
+ }
+ break;
+ }
+ }
+
+ pStmt->zEQP = idxAppendText(&rc, pStmt->zEQP, "%d|%d|%d|%s\n",
+ iSelectid, iOrder, iFrom, zDetail
+ );
+ }
+
+ for(pEntry=hIdx.pFirst; pEntry; pEntry=pEntry->pNext){
+ pStmt->zIdx = idxAppendText(&rc, pStmt->zIdx, "%s;\n", pEntry->zKey);
+ }
+
+ idxFinalize(&rc, pExplain);
+ }
+
+ find_indexes_out:
+ idxHashClear(&hIdx);
+ return rc;
+}
+
+static int idxAuthCallback(
+ void *pCtx,
+ int eOp,
+ const char *z3,
+ const char *z4,
+ const char *zDb,
+ const char *zTrigger
+){
+ int rc = SQLITE_OK;
+ if( eOp==SQLITE_INSERT || eOp==SQLITE_UPDATE || eOp==SQLITE_DELETE ){
+ if( sqlite3_stricmp(zDb, "main")==0 ){
+ sqlite3expert *p = (sqlite3expert*)pCtx;
+ IdxTable *pTab;
+ for(pTab=p->pTable; pTab; pTab=pTab->pNext){
+ if( 0==sqlite3_stricmp(z3, pTab->zName) ) break;
+ }
+ if( pTab ){
+ IdxWrite *pWrite;
+ for(pWrite=p->pWrite; pWrite; pWrite=pWrite->pNext){
+ if( pWrite->pTab==pTab && pWrite->eOp==eOp ) break;
+ }
+ if( pWrite==0 ){
+ pWrite = idxMalloc(&rc, sizeof(IdxWrite));
+ if( rc==SQLITE_OK ){
+ pWrite->pTab = pTab;
+ pWrite->eOp = eOp;
+ pWrite->pNext = p->pWrite;
+ p->pWrite = pWrite;
+ }
+ }
+ }
+ }
+ }
+ return rc;
+}
+
+static int idxProcessOneTrigger(
+ sqlite3expert *p,
+ IdxWrite *pWrite,
+ char **pzErr
+){
+ static const char *zInt = UNIQUE_TABLE_NAME;
+ static const char *zDrop = "DROP TABLE " UNIQUE_TABLE_NAME;
+ IdxTable *pTab = pWrite->pTab;
+ const char *zTab = pTab->zName;
+ const char *zSql =
+ "SELECT 'CREATE TEMP' || substr(sql, 7) FROM sqlite_master "
+ "WHERE tbl_name = %Q AND type IN ('table', 'trigger') "
+ "ORDER BY type;";
+ sqlite3_stmt *pSelect = 0;
+ int rc = SQLITE_OK;
+ char *zWrite = 0;
+
+ /* Create the table and its triggers in the temp schema */
+ rc = idxPrintfPrepareStmt(p->db, &pSelect, pzErr, zSql, zTab, zTab);
+ while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pSelect) ){
+ const char *zCreate = (const char*)sqlite3_column_text(pSelect, 0);
+ rc = sqlite3_exec(p->dbv, zCreate, 0, 0, pzErr);
+ }
+ idxFinalize(&rc, pSelect);
+
+ /* Rename the table in the temp schema to zInt */
+ if( rc==SQLITE_OK ){
+ char *z = sqlite3_mprintf("ALTER TABLE temp.%Q RENAME TO %Q", zTab, zInt);
+ if( z==0 ){
+ rc = SQLITE_NOMEM;
+ }else{
+ rc = sqlite3_exec(p->dbv, z, 0, 0, pzErr);
+ sqlite3_free(z);
+ }
+ }
+
+ switch( pWrite->eOp ){
+ case SQLITE_INSERT: {
+ int i;
+ zWrite = idxAppendText(&rc, zWrite, "INSERT INTO %Q VALUES(", zInt);
+ for(i=0; i<pTab->nCol; i++){
+ zWrite = idxAppendText(&rc, zWrite, "%s?", i==0 ? "" : ", ");
+ }
+ zWrite = idxAppendText(&rc, zWrite, ")");
+ break;
+ }
+ case SQLITE_UPDATE: {
+ int i;
+ zWrite = idxAppendText(&rc, zWrite, "UPDATE %Q SET ", zInt);
+ for(i=0; i<pTab->nCol; i++){
+ zWrite = idxAppendText(&rc, zWrite, "%s%Q=?", i==0 ? "" : ", ",
+ pTab->aCol[i].zName
+ );
+ }
+ break;
+ }
+ default: {
+ assert( pWrite->eOp==SQLITE_DELETE );
+ if( rc==SQLITE_OK ){
+ zWrite = sqlite3_mprintf("DELETE FROM %Q", zInt);
+ if( zWrite==0 ) rc = SQLITE_NOMEM;
+ }
+ }
+ }
+
+ if( rc==SQLITE_OK ){
+ sqlite3_stmt *pX = 0;
+ rc = sqlite3_prepare_v2(p->dbv, zWrite, -1, &pX, 0);
+ idxFinalize(&rc, pX);
+ if( rc!=SQLITE_OK ){
+ idxDatabaseError(p->dbv, pzErr);
+ }
+ }
+ sqlite3_free(zWrite);
+
+ if( rc==SQLITE_OK ){
+ rc = sqlite3_exec(p->dbv, zDrop, 0, 0, pzErr);
+ }
+
+ return rc;
+}
+
+static int idxProcessTriggers(sqlite3expert *p, char **pzErr){
+ int rc = SQLITE_OK;
+ IdxWrite *pEnd = 0;
+ IdxWrite *pFirst = p->pWrite;
+
+ while( rc==SQLITE_OK && pFirst!=pEnd ){
+ IdxWrite *pIter;
+ for(pIter=pFirst; rc==SQLITE_OK && pIter!=pEnd; pIter=pIter->pNext){
+ rc = idxProcessOneTrigger(p, pIter, pzErr);
+ }
+ pEnd = pFirst;
+ pFirst = p->pWrite;
+ }
+
+ return rc;
+}
+
+
+static int idxCreateVtabSchema(sqlite3expert *p, char **pzErrmsg){
+ int rc = idxRegisterVtab(p);
+ sqlite3_stmt *pSchema = 0;
+
+ /* For each table in the main db schema:
+ **
+ ** 1) Add an entry to the p->pTable list, and
+ ** 2) Create the equivalent virtual table in dbv.
+ */
+ rc = idxPrepareStmt(p->db, &pSchema, pzErrmsg,
+ "SELECT type, name, sql, 1 FROM sqlite_master "
+ "WHERE type IN ('table','view') AND name NOT LIKE 'sqlite_%%' "
+ " UNION ALL "
+ "SELECT type, name, sql, 2 FROM sqlite_master "
+ "WHERE type = 'trigger'"
+ " AND tbl_name IN(SELECT name FROM sqlite_master WHERE type = 'view') "
+ "ORDER BY 4, 1"
+ );
+ while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pSchema) ){
+ const char *zType = (const char*)sqlite3_column_text(pSchema, 0);
+ const char *zName = (const char*)sqlite3_column_text(pSchema, 1);
+ const char *zSql = (const char*)sqlite3_column_text(pSchema, 2);
+
+ if( zType[0]=='v' || zType[1]=='r' ){
+ rc = sqlite3_exec(p->dbv, zSql, 0, 0, pzErrmsg);
+ }else{
+ IdxTable *pTab;
+ rc = idxGetTableInfo(p->db, zName, &pTab, pzErrmsg);
+ if( rc==SQLITE_OK ){
+ int i;
+ char *zInner = 0;
+ char *zOuter = 0;
+ pTab->pNext = p->pTable;
+ p->pTable = pTab;
+
+ /* The statement the vtab will pass to sqlite3_declare_vtab() */
+ zInner = idxAppendText(&rc, 0, "CREATE TABLE x(");
+ for(i=0; i<pTab->nCol; i++){
+ zInner = idxAppendText(&rc, zInner, "%s%Q COLLATE %s",
+ (i==0 ? "" : ", "), pTab->aCol[i].zName, pTab->aCol[i].zColl
+ );
+ }
+ zInner = idxAppendText(&rc, zInner, ")");
+
+ /* The CVT statement to create the vtab */
+ zOuter = idxAppendText(&rc, 0,
+ "CREATE VIRTUAL TABLE %Q USING expert(%Q)", zName, zInner
+ );
+ if( rc==SQLITE_OK ){
+ rc = sqlite3_exec(p->dbv, zOuter, 0, 0, pzErrmsg);
+ }
+ sqlite3_free(zInner);
+ sqlite3_free(zOuter);
+ }
+ }
+ }
+ idxFinalize(&rc, pSchema);
+ return rc;
+}
+
+struct IdxSampleCtx {
+ int iTarget;
+ double target; /* Target nRet/nRow value */
+ double nRow; /* Number of rows seen */
+ double nRet; /* Number of rows returned */
+};
+
+static void idxSampleFunc(
+ sqlite3_context *pCtx,
+ int argc,
+ sqlite3_value **argv
+){
+ struct IdxSampleCtx *p = (struct IdxSampleCtx*)sqlite3_user_data(pCtx);
+ int bRet;
+
+ assert( argc==0 );
+ if( p->nRow==0.0 ){
+ bRet = 1;
+ }else{
+ bRet = (p->nRet / p->nRow) <= p->target;
+ if( bRet==0 ){
+ unsigned short rnd;
+ sqlite3_randomness(2, (void*)&rnd);
+ bRet = ((int)rnd % 100) <= p->iTarget;
+ }
+ }
+
+ sqlite3_result_int(pCtx, bRet);
+ p->nRow += 1.0;
+ p->nRet += (double)bRet;
+}
+
+struct IdxRemCtx {
+ int nSlot;
+ struct IdxRemSlot {
+ int eType; /* SQLITE_NULL, INTEGER, REAL, TEXT, BLOB */
+ i64 iVal; /* SQLITE_INTEGER value */
+ double rVal; /* SQLITE_FLOAT value */
+ int nByte; /* Bytes of space allocated at z */
+ int n; /* Size of buffer z */
+ char *z; /* SQLITE_TEXT/BLOB value */
+ } aSlot[1];
+};
+
+/*
+** Implementation of scalar function rem().
+*/
+static void idxRemFunc(
+ sqlite3_context *pCtx,
+ int argc,
+ sqlite3_value **argv
+){
+ struct IdxRemCtx *p = (struct IdxRemCtx*)sqlite3_user_data(pCtx);
+ struct IdxRemSlot *pSlot;
+ int iSlot;
+ assert( argc==2 );
+
+ iSlot = sqlite3_value_int(argv[0]);
+ assert( iSlot<=p->nSlot );
+ pSlot = &p->aSlot[iSlot];
+
+ switch( pSlot->eType ){
+ case SQLITE_NULL:
+ /* no-op */
+ break;
+
+ case SQLITE_INTEGER:
+ sqlite3_result_int64(pCtx, pSlot->iVal);
+ break;
+
+ case SQLITE_FLOAT:
+ sqlite3_result_double(pCtx, pSlot->rVal);
+ break;
+
+ case SQLITE_BLOB:
+ sqlite3_result_blob(pCtx, pSlot->z, pSlot->n, SQLITE_TRANSIENT);
+ break;
+
+ case SQLITE_TEXT:
+ sqlite3_result_text(pCtx, pSlot->z, pSlot->n, SQLITE_TRANSIENT);
+ break;
+ }
+
+ pSlot->eType = sqlite3_value_type(argv[1]);
+ switch( pSlot->eType ){
+ case SQLITE_NULL:
+ /* no-op */
+ break;
+
+ case SQLITE_INTEGER:
+ pSlot->iVal = sqlite3_value_int64(argv[1]);
+ break;
+
+ case SQLITE_FLOAT:
+ pSlot->rVal = sqlite3_value_double(argv[1]);
+ break;
+
+ case SQLITE_BLOB:
+ case SQLITE_TEXT: {
+ int nByte = sqlite3_value_bytes(argv[1]);
+ if( nByte>pSlot->nByte ){
+ char *zNew = (char*)sqlite3_realloc(pSlot->z, nByte*2);
+ if( zNew==0 ){
+ sqlite3_result_error_nomem(pCtx);
+ return;
+ }
+ pSlot->nByte = nByte*2;
+ pSlot->z = zNew;
+ }
+ pSlot->n = nByte;
+ if( pSlot->eType==SQLITE_BLOB ){
+ memcpy(pSlot->z, sqlite3_value_blob(argv[1]), nByte);
+ }else{
+ memcpy(pSlot->z, sqlite3_value_text(argv[1]), nByte);
+ }
+ break;
+ }
+ }
+}
+
+static int idxLargestIndex(sqlite3 *db, int *pnMax, char **pzErr){
+ int rc = SQLITE_OK;
+ const char *zMax =
+ "SELECT max(i.seqno) FROM "
+ " sqlite_master AS s, "
+ " pragma_index_list(s.name) AS l, "
+ " pragma_index_info(l.name) AS i "
+ "WHERE s.type = 'table'";
+ sqlite3_stmt *pMax = 0;
+
+ *pnMax = 0;
+ rc = idxPrepareStmt(db, &pMax, pzErr, zMax);
+ if( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pMax) ){
+ *pnMax = sqlite3_column_int(pMax, 0) + 1;
+ }
+ idxFinalize(&rc, pMax);
+
+ return rc;
+}
+
+static int idxPopulateOneStat1(
+ sqlite3expert *p,
+ sqlite3_stmt *pIndexXInfo,
+ sqlite3_stmt *pWriteStat,
+ const char *zTab,
+ const char *zIdx,
+ char **pzErr
+){
+ char *zCols = 0;
+ char *zOrder = 0;
+ char *zQuery = 0;
+ int nCol = 0;
+ int i;
+ sqlite3_stmt *pQuery = 0;
+ int *aStat = 0;
+ int rc = SQLITE_OK;
+
+ assert( p->iSample>0 );
+
+ /* Formulate the query text */
+ sqlite3_bind_text(pIndexXInfo, 1, zIdx, -1, SQLITE_STATIC);
+ while( SQLITE_OK==rc && SQLITE_ROW==sqlite3_step(pIndexXInfo) ){
+ const char *zComma = zCols==0 ? "" : ", ";
+ const char *zName = (const char*)sqlite3_column_text(pIndexXInfo, 0);
+ const char *zColl = (const char*)sqlite3_column_text(pIndexXInfo, 1);
+ zCols = idxAppendText(&rc, zCols,
+ "%sx.%Q IS rem(%d, x.%Q) COLLATE %s", zComma, zName, nCol, zName, zColl
+ );
+ zOrder = idxAppendText(&rc, zOrder, "%s%d", zComma, ++nCol);
+ }
+ if( rc==SQLITE_OK ){
+ if( p->iSample==100 ){
+ zQuery = sqlite3_mprintf(
+ "SELECT %s FROM %Q x ORDER BY %s", zCols, zTab, zOrder
+ );
+ }else{
+ zQuery = sqlite3_mprintf(
+ "SELECT %s FROM temp."UNIQUE_TABLE_NAME" x ORDER BY %s", zCols, zOrder
+ );
+ }
+ }
+ sqlite3_free(zCols);
+ sqlite3_free(zOrder);
+
+ /* Formulate the query text */
+ if( rc==SQLITE_OK ){
+ sqlite3 *dbrem = (p->iSample==100 ? p->db : p->dbv);
+ rc = idxPrepareStmt(dbrem, &pQuery, pzErr, zQuery);
+ }
+ sqlite3_free(zQuery);
+
+ if( rc==SQLITE_OK ){
+ aStat = (int*)idxMalloc(&rc, sizeof(int)*(nCol+1));
+ }
+ if( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pQuery) ){
+ IdxHashEntry *pEntry;
+ char *zStat = 0;
+ for(i=0; i<=nCol; i++) aStat[i] = 1;
+ while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pQuery) ){
+ aStat[0]++;
+ for(i=0; i<nCol; i++){
+ if( sqlite3_column_int(pQuery, i)==0 ) break;
+ }
+ for(/*no-op*/; i<nCol; i++){
+ aStat[i+1]++;
+ }
+ }
+
+ if( rc==SQLITE_OK ){
+ int s0 = aStat[0];
+ zStat = sqlite3_mprintf("%d", s0);
+ if( zStat==0 ) rc = SQLITE_NOMEM;
+ for(i=1; rc==SQLITE_OK && i<=nCol; i++){
+ zStat = idxAppendText(&rc, zStat, " %d", (s0+aStat[i]/2) / aStat[i]);
+ }
+ }
+
+ if( rc==SQLITE_OK ){
+ sqlite3_bind_text(pWriteStat, 1, zTab, -1, SQLITE_STATIC);
+ sqlite3_bind_text(pWriteStat, 2, zIdx, -1, SQLITE_STATIC);
+ sqlite3_bind_text(pWriteStat, 3, zStat, -1, SQLITE_STATIC);
+ sqlite3_step(pWriteStat);
+ rc = sqlite3_reset(pWriteStat);
+ }
+
+ pEntry = idxHashFind(&p->hIdx, zIdx, strlen(zIdx));
+ if( pEntry ){
+ assert( pEntry->zVal2==0 );
+ pEntry->zVal2 = zStat;
+ }else{
+ sqlite3_free(zStat);
+ }
+ }
+ sqlite3_free(aStat);
+ idxFinalize(&rc, pQuery);
+
+ return rc;
+}
+
+static int idxBuildSampleTable(sqlite3expert *p, const char *zTab){
+ int rc;
+ char *zSql;
+
+ rc = sqlite3_exec(p->dbv,"DROP TABLE IF EXISTS temp."UNIQUE_TABLE_NAME,0,0,0);
+ if( rc!=SQLITE_OK ) return rc;
+
+ zSql = sqlite3_mprintf(
+ "CREATE TABLE temp." UNIQUE_TABLE_NAME " AS SELECT * FROM %Q", zTab
+ );
+ if( zSql==0 ) return SQLITE_NOMEM;
+ rc = sqlite3_exec(p->dbv, zSql, 0, 0, 0);
+ sqlite3_free(zSql);
+
+ return rc;
+}
+
+/*
+** This function is called as part of sqlite3_expert_analyze(). Candidate
+** indexes have already been created in database sqlite3expert.dbm, this
+** function populates sqlite_stat1 table in the same database.
+**
+** The stat1 data is generated by querying the
+*/
+static int idxPopulateStat1(sqlite3expert *p, char **pzErr){
+ int rc = SQLITE_OK;
+ int nMax =0;
+ struct IdxRemCtx *pCtx = 0;
+ struct IdxSampleCtx samplectx;
+ int i;
+ i64 iPrev = -100000;
+ sqlite3_stmt *pAllIndex = 0;
+ sqlite3_stmt *pIndexXInfo = 0;
+ sqlite3_stmt *pWrite = 0;
+
+ const char *zAllIndex =
+ "SELECT s.rowid, s.name, l.name FROM "
+ " sqlite_master AS s, "
+ " pragma_index_list(s.name) AS l "
+ "WHERE s.type = 'table'";
+ const char *zIndexXInfo =
+ "SELECT name, coll FROM pragma_index_xinfo(?) WHERE key";
+ const char *zWrite = "INSERT INTO sqlite_stat1 VALUES(?, ?, ?)";
+
+ /* If iSample==0, no sqlite_stat1 data is required. */
+ if( p->iSample==0 ) return SQLITE_OK;
+
+ rc = idxLargestIndex(p->dbm, &nMax, pzErr);
+ if( nMax<=0 || rc!=SQLITE_OK ) return rc;
+
+ rc = sqlite3_exec(p->dbm, "ANALYZE; PRAGMA writable_schema=1", 0, 0, 0);
+
+ if( rc==SQLITE_OK ){
+ int nByte = sizeof(struct IdxRemCtx) + (sizeof(struct IdxRemSlot) * nMax);
+ pCtx = (struct IdxRemCtx*)idxMalloc(&rc, nByte);
+ }
+
+ if( rc==SQLITE_OK ){
+ sqlite3 *dbrem = (p->iSample==100 ? p->db : p->dbv);
+ rc = sqlite3_create_function(
+ dbrem, "rem", 2, SQLITE_UTF8, (void*)pCtx, idxRemFunc, 0, 0
+ );
+ }
+ if( rc==SQLITE_OK ){
+ rc = sqlite3_create_function(
+ p->db, "sample", 0, SQLITE_UTF8, (void*)&samplectx, idxSampleFunc, 0, 0
+ );
+ }
+
+ if( rc==SQLITE_OK ){
+ pCtx->nSlot = nMax+1;
+ rc = idxPrepareStmt(p->dbm, &pAllIndex, pzErr, zAllIndex);
+ }
+ if( rc==SQLITE_OK ){
+ rc = idxPrepareStmt(p->dbm, &pIndexXInfo, pzErr, zIndexXInfo);
+ }
+ if( rc==SQLITE_OK ){
+ rc = idxPrepareStmt(p->dbm, &pWrite, pzErr, zWrite);
+ }
+
+ while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pAllIndex) ){
+ i64 iRowid = sqlite3_column_int64(pAllIndex, 0);
+ const char *zTab = (const char*)sqlite3_column_text(pAllIndex, 1);
+ const char *zIdx = (const char*)sqlite3_column_text(pAllIndex, 2);
+ if( p->iSample<100 && iPrev!=iRowid ){
+ samplectx.target = (double)p->iSample / 100.0;
+ samplectx.iTarget = p->iSample;
+ samplectx.nRow = 0.0;
+ samplectx.nRet = 0.0;
+ rc = idxBuildSampleTable(p, zTab);
+ if( rc!=SQLITE_OK ) break;
+ }
+ rc = idxPopulateOneStat1(p, pIndexXInfo, pWrite, zTab, zIdx, pzErr);
+ iPrev = iRowid;
+ }
+ if( rc==SQLITE_OK && p->iSample<100 ){
+ rc = sqlite3_exec(p->dbv,
+ "DROP TABLE IF EXISTS temp." UNIQUE_TABLE_NAME, 0,0,0
+ );
+ }
+
+ idxFinalize(&rc, pAllIndex);
+ idxFinalize(&rc, pIndexXInfo);
+ idxFinalize(&rc, pWrite);
+
+ for(i=0; i<pCtx->nSlot; i++){
+ sqlite3_free(pCtx->aSlot[i].z);
+ }
+ sqlite3_free(pCtx);
+
+ if( rc==SQLITE_OK ){
+ rc = sqlite3_exec(p->dbm, "ANALYZE sqlite_master", 0, 0, 0);
+ }
+
+ sqlite3_exec(p->db, "DROP TABLE IF EXISTS temp."UNIQUE_TABLE_NAME,0,0,0);
+ return rc;
+}
+
+/*
+** Allocate a new sqlite3expert object.
+*/
+sqlite3expert *sqlite3_expert_new(sqlite3 *db, char **pzErrmsg){
+ int rc = SQLITE_OK;
+ sqlite3expert *pNew;
+
+ pNew = (sqlite3expert*)idxMalloc(&rc, sizeof(sqlite3expert));
+
+ /* Open two in-memory databases to work with. The "vtab database" (dbv)
+ ** will contain a virtual table corresponding to each real table in
+ ** the user database schema, and a copy of each view. It is used to
+ ** collect information regarding the WHERE, ORDER BY and other clauses
+ ** of the user's query.
+ */
+ if( rc==SQLITE_OK ){
+ pNew->db = db;
+ pNew->iSample = 100;
+ rc = sqlite3_open(":memory:", &pNew->dbv);
+ }
+ if( rc==SQLITE_OK ){
+ rc = sqlite3_open(":memory:", &pNew->dbm);
+ if( rc==SQLITE_OK ){
+ sqlite3_db_config(pNew->dbm, SQLITE_DBCONFIG_FULL_EQP, 1, (int*)0);
+ }
+ }
+
+
+ /* Copy the entire schema of database [db] into [dbm]. */
+ if( rc==SQLITE_OK ){
+ sqlite3_stmt *pSql;
+ rc = idxPrintfPrepareStmt(pNew->db, &pSql, pzErrmsg,
+ "SELECT sql FROM sqlite_master WHERE name NOT LIKE 'sqlite_%%'"
+ );
+ while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pSql) ){
+ const char *zSql = (const char*)sqlite3_column_text(pSql, 0);
+ rc = sqlite3_exec(pNew->dbm, zSql, 0, 0, pzErrmsg);
+ }
+ idxFinalize(&rc, pSql);
+ }
+
+ /* Create the vtab schema */
+ if( rc==SQLITE_OK ){
+ rc = idxCreateVtabSchema(pNew, pzErrmsg);
+ }
+
+ /* Register the auth callback with dbv */
+ if( rc==SQLITE_OK ){
+ sqlite3_set_authorizer(pNew->dbv, idxAuthCallback, (void*)pNew);
+ }
+
+ /* If an error has occurred, free the new object and reutrn NULL. Otherwise,
+ ** return the new sqlite3expert handle. */
+ if( rc!=SQLITE_OK ){
+ sqlite3_expert_destroy(pNew);
+ pNew = 0;
+ }
+ return pNew;
+}
+
+/*
+** Configure an sqlite3expert object.
+*/
+int sqlite3_expert_config(sqlite3expert *p, int op, ...){
+ int rc = SQLITE_OK;
+ va_list ap;
+ va_start(ap, op);
+ switch( op ){
+ case EXPERT_CONFIG_SAMPLE: {
+ int iVal = va_arg(ap, int);
+ if( iVal<0 ) iVal = 0;
+ if( iVal>100 ) iVal = 100;
+ p->iSample = iVal;
+ break;
+ }
+ default:
+ rc = SQLITE_NOTFOUND;
+ break;
+ }
+
+ va_end(ap);
+ return rc;
+}
+
+/*
+** Add an SQL statement to the analysis.
+*/
+int sqlite3_expert_sql(
+ sqlite3expert *p, /* From sqlite3_expert_new() */
+ const char *zSql, /* SQL statement to add */
+ char **pzErr /* OUT: Error message (if any) */
+){
+ IdxScan *pScanOrig = p->pScan;
+ IdxStatement *pStmtOrig = p->pStatement;
+ int rc = SQLITE_OK;
+ const char *zStmt = zSql;
+
+ if( p->bRun ) return SQLITE_MISUSE;
+
+ while( rc==SQLITE_OK && zStmt && zStmt[0] ){
+ sqlite3_stmt *pStmt = 0;
+ rc = sqlite3_prepare_v2(p->dbv, zStmt, -1, &pStmt, &zStmt);
+ if( rc==SQLITE_OK ){
+ if( pStmt ){
+ IdxStatement *pNew;
+ const char *z = sqlite3_sql(pStmt);
+ int n = strlen(z);
+ pNew = (IdxStatement*)idxMalloc(&rc, sizeof(IdxStatement) + n+1);
+ if( rc==SQLITE_OK ){
+ pNew->zSql = (char*)&pNew[1];
+ memcpy(pNew->zSql, z, n+1);
+ pNew->pNext = p->pStatement;
+ if( p->pStatement ) pNew->iId = p->pStatement->iId+1;
+ p->pStatement = pNew;
+ }
+ sqlite3_finalize(pStmt);
+ }
+ }else{
+ idxDatabaseError(p->dbv, pzErr);
+ }
+ }
+
+ if( rc!=SQLITE_OK ){
+ idxScanFree(p->pScan, pScanOrig);
+ idxStatementFree(p->pStatement, pStmtOrig);
+ p->pScan = pScanOrig;
+ p->pStatement = pStmtOrig;
+ }
+
+ return rc;
+}
+
+int sqlite3_expert_analyze(sqlite3expert *p, char **pzErr){
+ int rc;
+ IdxHashEntry *pEntry;
+
+ /* Do trigger processing to collect any extra IdxScan structures */
+ rc = idxProcessTriggers(p, pzErr);
+
+ /* Create candidate indexes within the in-memory database file */
+ if( rc==SQLITE_OK ){
+ rc = idxCreateCandidates(p, pzErr);
+ }
+
+ /* Generate the stat1 data */
+ if( rc==SQLITE_OK ){
+ rc = idxPopulateStat1(p, pzErr);
+ }
+
+ /* Formulate the EXPERT_REPORT_CANDIDATES text */
+ for(pEntry=p->hIdx.pFirst; pEntry; pEntry=pEntry->pNext){
+ p->zCandidates = idxAppendText(&rc, p->zCandidates,
+ "%s;%s%s\n", pEntry->zVal,
+ pEntry->zVal2 ? " -- stat1: " : "", pEntry->zVal2
+ );
+ }
+
+ /* Figure out which of the candidate indexes are preferred by the query
+ ** planner and report the results to the user. */
+ if( rc==SQLITE_OK ){
+ rc = idxFindIndexes(p, pzErr);
+ }
+
+ if( rc==SQLITE_OK ){
+ p->bRun = 1;
+ }
+ return rc;
+}
+
+/*
+** Return the total number of statements that have been added to this
+** sqlite3expert using sqlite3_expert_sql().
+*/
+int sqlite3_expert_count(sqlite3expert *p){
+ int nRet = 0;
+ if( p->pStatement ) nRet = p->pStatement->iId+1;
+ return nRet;
+}
+
+/*
+** Return a component of the report.
+*/
+const char *sqlite3_expert_report(sqlite3expert *p, int iStmt, int eReport){
+ const char *zRet = 0;
+ IdxStatement *pStmt;
+
+ if( p->bRun==0 ) return 0;
+ for(pStmt=p->pStatement; pStmt && pStmt->iId!=iStmt; pStmt=pStmt->pNext);
+ switch( eReport ){
+ case EXPERT_REPORT_SQL:
+ if( pStmt ) zRet = pStmt->zSql;
+ break;
+ case EXPERT_REPORT_INDEXES:
+ if( pStmt ) zRet = pStmt->zIdx;
+ break;
+ case EXPERT_REPORT_PLAN:
+ if( pStmt ) zRet = pStmt->zEQP;
+ break;
+ case EXPERT_REPORT_CANDIDATES:
+ zRet = p->zCandidates;
+ break;
+ }
+ return zRet;
+}
+
+/*
+** Free an sqlite3expert object.
+*/
+void sqlite3_expert_destroy(sqlite3expert *p){
+ if( p ){
+ sqlite3_close(p->dbm);
+ sqlite3_close(p->dbv);
+ idxScanFree(p->pScan, 0);
+ idxStatementFree(p->pStatement, 0);
+ idxTableFree(p->pTable);
+ idxWriteFree(p->pWrite);
+ idxHashClear(&p->hIdx);
+ sqlite3_free(p->zCandidates);
+ sqlite3_free(p);
+ }
+}
+
+#endif /* !defined(SQLITE_TEST) || defined(SQLITE_ENABLE_WHEREINFO_HOOK) */
+
projects / thirdparty / sqlite.git / commitdiff
