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lightning-sunbird  0.9+nobinonly
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analyze.c File Reference
#include "sqliteInt.h"

Go to the source code of this file.

Classes

struct  analysisInfo

Typedefs

typedef struct analysisInfo

Functions

static void openStatTable (Parse *pParse, int iDb, int iStatCur, const char *zWhere)
static void analyzeOneTable (Parse *pParse, Table *pTab, int iStatCur, int iMem)
static void loadAnalysis (Parse *pParse, int iDb)
static void analyzeDatabase (Parse *pParse, int iDb)
static void analyzeTable (Parse *pParse, Table *pTab)
void sqlite3Analyze (Parse *pParse, Token *pName1, Token *pName2)
static int analysisLoader (void *pData, int argc, char **argv, char **azNotUsed)
void sqlite3AnalysisLoad (sqlite3 *db, int iDb)

Class Documentation

struct analysisInfo

Definition at line 331 of file analyze.c.

Collaboration diagram for analysisInfo:
Class Members
sqlite3 * db
const char * zDatabase

Typedef Documentation

typedef struct analysisInfo

Definition at line 330 of file analyze.c.


Function Documentation

static int analysisLoader ( void pData,
int  argc,
char **  argv,
char **  azNotUsed 
) [static]

Definition at line 343 of file analyze.c.

                                                                               {
  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;
}

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static void analyzeDatabase ( Parse pParse,
int  iDb 
) [static]

Definition at line 231 of file analyze.c.

                                                   {
  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);
}

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static void analyzeOneTable ( Parse pParse,
Table pTab,
int  iStatCur,
int  iMem 
) [static]

Definition at line 81 of file analyze.c.

 {
  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( pTab==0 || pTab->pIndex==0 ){
    /* Do no analysis for tables that have no indices */
    return;
  }

  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_stmt1 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, 0);
    sqlite3VdbeJumpHere(v, addr);
  }
}

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static void analyzeTable ( Parse pParse,
Table pTab 
) [static]

Definition at line 253 of file analyze.c.

                                                    {
  int iDb;
  int iStatCur;

  assert( pTab!=0 );
  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);
}

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static void loadAnalysis ( Parse pParse,
int  iDb 
) [static]

Definition at line 223 of file analyze.c.

                                                {
  Vdbe *v = sqlite3GetVdbe(pParse);
  sqlite3VdbeAddOp(v, OP_LoadAnalysis, iDb, 0);
}

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static void openStatTable ( Parse pParse,
int  iDb,
int  iStatCur,
const char *  zWhere 
) [static]

Definition at line 27 of file analyze.c.

 {
  sqlite3 *db = pParse->db;
  Db *pDb;
  int iRootPage;
  Table *pStat;
  Vdbe *v = sqlite3GetVdbe(pParse);

  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);
}

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void sqlite3AnalysisLoad ( sqlite3 db,
int  iDb 
)

Definition at line 374 of file analyze.c.

                                              {
  analysisInfo sInfo;
  HashElem *i;
  char *zSql;

  /* Clear any prior statistics */
  for(i=sqliteHashFirst(&db->aDb[iDb].pSchema->idxHash);i;i=sqliteHashNext(i)){
    Index *pIdx = 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;
  }


  /* Load new statistics out of the sqlite_stat1 table */
  zSql = sqlite3MPrintf("SELECT idx, stat FROM %Q.sqlite_stat1",
                        sInfo.zDatabase);
  sqlite3SafetyOff(db);
  sqlite3_exec(db, zSql, analysisLoader, &sInfo, 0);
  sqlite3SafetyOn(db);
  sqliteFree(zSql);
}

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void sqlite3Analyze ( Parse pParse,
Token pName1,
Token pName2 
)

Definition at line 278 of file analyze.c.

                                                                {
  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. */
  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(pName1);
      pTab = sqlite3LocateTable(pParse, z, 0);
      sqliteFree(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(pTableName);
      pTab = sqlite3LocateTable(pParse, z, zDb);
      sqliteFree(z);
      if( pTab ){
        analyzeTable(pParse, pTab);
      }
    }   
  }
}

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