--- a/engine/sqlite/src/analyze.cpp Wed May 26 10:44:32 2010 +0100
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,420 +0,0 @@
-/*
-** 2005 July 8
-**
-** 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.
-**
-*************************************************************************
-** This file contains code associated with the ANALYZE command.
-**
-** @(#) $Id: analyze.cpp 1282 2008-11-13 09:31:33Z LarsPson $
-*/
-#ifndef SQLITE_OMIT_ANALYZE
-#include "sqliteInt.h"
-
-/*
-** This routine generates code that opens the sqlite_stat1 table on cursor
-** iStatCur.
-**
-** If the sqlite_stat1 tables does not previously exist, it is created.
-** If it does previously exist, all entires associated with table zWhere
-** are removed. If zWhere==0 then all entries are removed.
-*/
-static void openStatTable(
- Parse *pParse, /* Parsing context */
- int iDb, /* The database we are looking in */
- int iStatCur, /* Open the sqlite_stat1 table on this cursor */
- const char *zWhere /* Delete entries associated with this table */
-){
- sqlite3 *db = pParse->db;
- Db *pDb;
- int iRootPage;
- Table *pStat;
- Vdbe *v = sqlite3GetVdbe(pParse);
-
- if( v==0 ) return;
- assert( sqlite3BtreeHoldsAllMutexes(db) );
- assert( sqlite3VdbeDb(v)==db );
- pDb = &db->aDb[iDb];
- if( (pStat = sqlite3FindTable(db, "sqlite_stat1", pDb->zName))==0 ){
- /* The sqlite_stat1 tables does not exist. Create it.
- ** Note that a side-effect of the CREATE TABLE statement is to leave
- ** the rootpage of the new table on the top of the stack. This is
- ** important because the OpenWrite opcode below will be needing it. */
- sqlite3NestedParse(pParse,
- "CREATE TABLE %Q.sqlite_stat1(tbl,idx,stat)",
- pDb->zName
- );
- iRootPage = 0; /* Cause rootpage to be taken from top of stack */
- }else if( zWhere ){
- /* The sqlite_stat1 table exists. Delete all entries associated with
- ** the table zWhere. */
- sqlite3NestedParse(pParse,
- "DELETE FROM %Q.sqlite_stat1 WHERE tbl=%Q",
- pDb->zName, zWhere
- );
- iRootPage = pStat->tnum;
- }else{
- /* The sqlite_stat1 table already exists. Delete all rows. */
- iRootPage = pStat->tnum;
- sqlite3VdbeAddOp(v, OP_Clear, pStat->tnum, iDb);
- }
-
- /* Open the sqlite_stat1 table for writing. Unless it was created
- ** by this vdbe program, lock it for writing at the shared-cache level.
- ** If this vdbe did create the sqlite_stat1 table, then it must have
- ** already obtained a schema-lock, making the write-lock redundant.
- */
- if( iRootPage>0 ){
- sqlite3TableLock(pParse, iDb, iRootPage, 1, "sqlite_stat1");
- }
- sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
- sqlite3VdbeAddOp(v, OP_OpenWrite, iStatCur, iRootPage);
- sqlite3VdbeAddOp(v, OP_SetNumColumns, iStatCur, 3);
-}
-
-/*
-** Generate code to do an analysis of all indices associated with
-** a single table.
-*/
-static void analyzeOneTable(
- Parse *pParse, /* Parser context */
- Table *pTab, /* Table whose indices are to be analyzed */
- int iStatCur, /* Cursor that writes to the sqlite_stat1 table */
- int iMem /* Available memory locations begin here */
-){
- Index *pIdx; /* An index to being analyzed */
- int iIdxCur; /* Cursor number for index being analyzed */
- int nCol; /* Number of columns in the index */
- Vdbe *v; /* The virtual machine being built up */
- int i; /* Loop counter */
- int topOfLoop; /* The top of the loop */
- int endOfLoop; /* The end of the loop */
- int addr; /* The address of an instruction */
- int iDb; /* Index of database containing pTab */
-
- v = sqlite3GetVdbe(pParse);
- if( v==0 || pTab==0 || pTab->pIndex==0 ){
- /* Do no analysis for tables that have no indices */
- return;
- }
- assert( sqlite3BtreeHoldsAllMutexes(pParse->db) );
- iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
- assert( iDb>=0 );
-#ifndef SQLITE_OMIT_AUTHORIZATION
- if( sqlite3AuthCheck(pParse, SQLITE_ANALYZE, pTab->zName, 0,
- pParse->db->aDb[iDb].zName ) ){
- return;
- }
-#endif
-
- /* Establish a read-lock on the table at the shared-cache level. */
- sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
-
- iIdxCur = pParse->nTab;
- for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
- KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIdx);
-
- /* Open a cursor to the index to be analyzed
- */
- assert( iDb==sqlite3SchemaToIndex(pParse->db, pIdx->pSchema) );
- sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
- VdbeComment((v, "# %s", pIdx->zName));
- sqlite3VdbeOp3(v, OP_OpenRead, iIdxCur, pIdx->tnum,
- (char *)pKey, P3_KEYINFO_HANDOFF);
- nCol = pIdx->nColumn;
- if( iMem+nCol*2>=pParse->nMem ){
- pParse->nMem = iMem+nCol*2+1;
- }
- sqlite3VdbeAddOp(v, OP_SetNumColumns, iIdxCur, nCol+1);
-
- /* Memory cells are used as follows:
- **
- ** mem[iMem]: The total number of rows in the table.
- ** mem[iMem+1]: Number of distinct values in column 1
- ** ...
- ** mem[iMem+nCol]: Number of distinct values in column N
- ** mem[iMem+nCol+1] Last observed value of column 1
- ** ...
- ** mem[iMem+nCol+nCol]: Last observed value of column N
- **
- ** Cells iMem through iMem+nCol are initialized to 0. The others
- ** are initialized to NULL.
- */
- for(i=0; i<=nCol; i++){
- sqlite3VdbeAddOp(v, OP_MemInt, 0, iMem+i);
- }
- for(i=0; i<nCol; i++){
- sqlite3VdbeAddOp(v, OP_MemNull, iMem+nCol+i+1, 0);
- }
-
- /* Do the analysis.
- */
- endOfLoop = sqlite3VdbeMakeLabel(v);
- sqlite3VdbeAddOp(v, OP_Rewind, iIdxCur, endOfLoop);
- topOfLoop = sqlite3VdbeCurrentAddr(v);
- sqlite3VdbeAddOp(v, OP_MemIncr, 1, iMem);
- for(i=0; i<nCol; i++){
- sqlite3VdbeAddOp(v, OP_Column, iIdxCur, i);
- sqlite3VdbeAddOp(v, OP_MemLoad, iMem+nCol+i+1, 0);
- sqlite3VdbeAddOp(v, OP_Ne, 0x100, 0);
- }
- sqlite3VdbeAddOp(v, OP_Goto, 0, endOfLoop);
- for(i=0; i<nCol; i++){
- addr = sqlite3VdbeAddOp(v, OP_MemIncr, 1, iMem+i+1);
- sqlite3VdbeChangeP2(v, topOfLoop + 3*i + 3, addr);
- sqlite3VdbeAddOp(v, OP_Column, iIdxCur, i);
- sqlite3VdbeAddOp(v, OP_MemStore, iMem+nCol+i+1, 1);
- }
- sqlite3VdbeResolveLabel(v, endOfLoop);
- sqlite3VdbeAddOp(v, OP_Next, iIdxCur, topOfLoop);
- sqlite3VdbeAddOp(v, OP_Close, iIdxCur, 0);
-
- /* Store the results.
- **
- ** The result is a single row of the sqlite_stat1 table. The first
- ** two columns are the names of the table and index. The third column
- ** is a string composed of a list of integer statistics about the
- ** index. The first integer in the list is the total number of entires
- ** in the index. There is one additional integer in the list for each
- ** column of the table. This additional integer is a guess of how many
- ** rows of the table the index will select. If D is the count of distinct
- ** values and K is the total number of rows, then the integer is computed
- ** as:
- **
- ** I = (K+D-1)/D
- **
- ** If K==0 then no entry is made into the sqlite_stat1 table.
- ** If K>0 then it is always the case the D>0 so division by zero
- ** is never possible.
- */
- sqlite3VdbeAddOp(v, OP_MemLoad, iMem, 0);
- addr = sqlite3VdbeAddOp(v, OP_IfNot, 0, 0);
- sqlite3VdbeAddOp(v, OP_NewRowid, iStatCur, 0);
- sqlite3VdbeOp3(v, OP_String8, 0, 0, pTab->zName, 0);
- sqlite3VdbeOp3(v, OP_String8, 0, 0, pIdx->zName, 0);
- sqlite3VdbeAddOp(v, OP_MemLoad, iMem, 0);
- sqlite3VdbeOp3(v, OP_String8, 0, 0, " ", 0);
- for(i=0; i<nCol; i++){
- sqlite3VdbeAddOp(v, OP_MemLoad, iMem, 0);
- sqlite3VdbeAddOp(v, OP_MemLoad, iMem+i+1, 0);
- sqlite3VdbeAddOp(v, OP_Add, 0, 0);
- sqlite3VdbeAddOp(v, OP_AddImm, -1, 0);
- sqlite3VdbeAddOp(v, OP_MemLoad, iMem+i+1, 0);
- sqlite3VdbeAddOp(v, OP_Divide, 0, 0);
- sqlite3VdbeAddOp(v, OP_ToInt, 0, 0);
- if( i==nCol-1 ){
- sqlite3VdbeAddOp(v, OP_Concat, nCol*2-1, 0);
- }else{
- sqlite3VdbeAddOp(v, OP_Dup, 1, 0);
- }
- }
- sqlite3VdbeOp3(v, OP_MakeRecord, 3, 0, "aaa", 0);
- sqlite3VdbeAddOp(v, OP_Insert, iStatCur, OPFLAG_APPEND);
- sqlite3VdbeJumpHere(v, addr);
- }
-}
-
-/*
-** Generate code that will cause the most recent index analysis to
-** be laoded into internal hash tables where is can be used.
-*/
-static void loadAnalysis(Parse *pParse, int iDb){
- Vdbe *v = sqlite3GetVdbe(pParse);
- if( v ){
- sqlite3VdbeAddOp(v, OP_LoadAnalysis, iDb, 0);
- }
-}
-
-/*
-** Generate code that will do an analysis of an entire database
-*/
-static void analyzeDatabase(Parse *pParse, int iDb){
- sqlite3 *db = pParse->db;
- Schema *pSchema = db->aDb[iDb].pSchema; /* Schema of database iDb */
- HashElem *k;
- int iStatCur;
- int iMem;
-
- sqlite3BeginWriteOperation(pParse, 0, iDb);
- iStatCur = pParse->nTab++;
- openStatTable(pParse, iDb, iStatCur, 0);
- iMem = pParse->nMem;
- for(k=sqliteHashFirst(&pSchema->tblHash); k; k=sqliteHashNext(k)){
- Table *pTab = (Table*)sqliteHashData(k);
- analyzeOneTable(pParse, pTab, iStatCur, iMem);
- }
- loadAnalysis(pParse, iDb);
-}
-
-/*
-** Generate code that will do an analysis of a single table in
-** a database.
-*/
-static void analyzeTable(Parse *pParse, Table *pTab){
- int iDb;
- int iStatCur;
-
- assert( pTab!=0 );
- assert( sqlite3BtreeHoldsAllMutexes(pParse->db) );
- iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
- sqlite3BeginWriteOperation(pParse, 0, iDb);
- iStatCur = pParse->nTab++;
- openStatTable(pParse, iDb, iStatCur, pTab->zName);
- analyzeOneTable(pParse, pTab, iStatCur, pParse->nMem);
- loadAnalysis(pParse, iDb);
-}
-
-/*
-** Generate code for the ANALYZE command. The parser calls this routine
-** when it recognizes an ANALYZE command.
-**
-** ANALYZE -- 1
-** ANALYZE <database> -- 2
-** ANALYZE ?<database>.?<tablename> -- 3
-**
-** Form 1 causes all indices in all attached databases to be analyzed.
-** Form 2 analyzes all indices the single database named.
-** Form 3 analyzes all indices associated with the named table.
-*/
-void sqlite3Analyze(Parse *pParse, Token *pName1, Token *pName2){
- sqlite3 *db = pParse->db;
- int iDb;
- int i;
- char *z, *zDb;
- Table *pTab;
- Token *pTableName;
-
- /* Read the database schema. If an error occurs, leave an error message
- ** and code in pParse and return NULL. */
- assert( sqlite3BtreeHoldsAllMutexes(pParse->db) );
- if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
- return;
- }
-
- if( pName1==0 ){
- /* Form 1: Analyze everything */
- for(i=0; i<db->nDb; i++){
- if( i==1 ) continue; /* Do not analyze the TEMP database */
- analyzeDatabase(pParse, i);
- }
- }else if( pName2==0 || pName2->n==0 ){
- /* Form 2: Analyze the database or table named */
- iDb = sqlite3FindDb(db, pName1);
- if( iDb>=0 ){
- analyzeDatabase(pParse, iDb);
- }else{
- z = sqlite3NameFromToken(db, pName1);
- if( z ){
- pTab = sqlite3LocateTable(pParse, z, 0);
- sqlite3_free(z);
- if( pTab ){
- analyzeTable(pParse, pTab);
- }
- }
- }
- }else{
- /* Form 3: Analyze the fully qualified table name */
- iDb = sqlite3TwoPartName(pParse, pName1, pName2, &pTableName);
- if( iDb>=0 ){
- zDb = db->aDb[iDb].zName;
- z = sqlite3NameFromToken(db, pTableName);
- if( z ){
- pTab = sqlite3LocateTable(pParse, z, zDb);
- sqlite3_free(z);
- if( pTab ){
- analyzeTable(pParse, pTab);
- }
- }
- }
- }
-}
-
-/*
-** Used to pass information from the analyzer reader through to the
-** callback routine.
-*/
-typedef struct analysisInfo analysisInfo;
-struct analysisInfo {
- sqlite3 *db;
- const char *zDatabase;
-};
-
-/*
-** This callback is invoked once for each index when reading the
-** sqlite_stat1 table.
-**
-** argv[0] = name of the index
-** argv[1] = results of analysis - on integer for each column
-*/
-static int analysisLoader(void *pData, int argc, char **argv, char **azNotUsed){
- analysisInfo *pInfo = (analysisInfo*)pData;
- Index *pIndex;
- int i, c;
- unsigned int v;
- const char *z;
-
- assert( argc==2 );
- if( argv==0 || argv[0]==0 || argv[1]==0 ){
- return 0;
- }
- pIndex = sqlite3FindIndex(pInfo->db, argv[0], pInfo->zDatabase);
- if( pIndex==0 ){
- return 0;
- }
- z = argv[1];
- for(i=0; *z && i<=pIndex->nColumn; i++){
- v = 0;
- while( (c=z[0])>='0' && c<='9' ){
- v = v*10 + c - '0';
- z++;
- }
- pIndex->aiRowEst[i] = v;
- if( *z==' ' ) z++;
- }
- return 0;
-}
-
-/*
-** Load the content of the sqlite_stat1 table into the index hash tables.
-*/
-int sqlite3AnalysisLoad(sqlite3 *db, int iDb){
- analysisInfo sInfo;
- HashElem *i;
- char *zSql;
- int rc;
-
- assert( iDb>=0 && iDb<db->nDb );
- assert( db->aDb[iDb].pBt!=0 );
- assert( sqlite3BtreeHoldsMutex(db->aDb[iDb].pBt) );
-
- /* Clear any prior statistics */
- for(i=sqliteHashFirst(&db->aDb[iDb].pSchema->idxHash);i;i=sqliteHashNext(i)){
- Index *pIdx = (Index *)sqliteHashData(i);
- sqlite3DefaultRowEst(pIdx);
- }
-
- /* Check to make sure the sqlite_stat1 table existss */
- sInfo.db = db;
- sInfo.zDatabase = db->aDb[iDb].zName;
- if( sqlite3FindTable(db, "sqlite_stat1", sInfo.zDatabase)==0 ){
- return SQLITE_ERROR;
- }
-
-
- /* Load new statistics out of the sqlite_stat1 table */
- zSql = sqlite3MPrintf(db, "SELECT idx, stat FROM %Q.sqlite_stat1",
- sInfo.zDatabase);
- sqlite3SafetyOff(db);
- rc = sqlite3_exec(db, zSql, analysisLoader, &sInfo, 0);
- sqlite3SafetyOn(db);
- sqlite3_free(zSql);
- return rc;
-}
-
-
-#endif /* SQLITE_OMIT_ANALYZE */