diff -r 5f8e5adbbed9 -r 29cda98b007e engine/sqlite/src/analyze.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/engine/sqlite/src/analyze.cpp	Thu Feb 25 14:29:19 2010 +0000
@@ -0,0 +1,420 @@
+/*
+** 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 */