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SQLite training in Houston TX on 2019-11-05 (details)
Part of the 2019 Tcl Conference

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Overview
Comment:Further refinements to the sqlite3_normalized_sql() interface. TH3 now gives 100% MC/DC on that interface.
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Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA3-256: c96bf6cca220e363b099455ce35195ce7e89d374a52dc787f56e7b11e587bced
User & Date: drh 2018-12-10 20:01:40
Context
2018-12-11
12:20
Small performance improvement in the sqlite3_bind() family of interfaces. check-in: 1dc0c3df user: drh tags: trunk
2018-12-10
20:01
Further refinements to the sqlite3_normalized_sql() interface. TH3 now gives 100% MC/DC on that interface. check-in: c96bf6cc user: drh tags: trunk
18:15
Refactor the sqlite3_normalized_sql() implementation. check-in: 06e955e5 user: drh tags: trunk
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to src/resolve.c.

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      ** Someday, I hope to get rid of this hack. Unfortunately there is
      ** a huge amount of legacy SQL that uses it. So for now, we just
      ** issue a warning.
      */
      sqlite3_log(SQLITE_WARNING,
        "double-quoted string literal: \"%w\"", zCol);
#ifdef SQLITE_ENABLE_NORMALIZE
      sqlite3VdbeAddDblquoteStr(db,pParse->pVdbe, zCol);
#endif
      pExpr->op = TK_STRING;
      pExpr->y.pTab = 0;
      return WRC_Prune;
    }
    if( sqlite3ExprIdToTrueFalse(pExpr) ){
      return WRC_Prune;







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      ** Someday, I hope to get rid of this hack. Unfortunately there is
      ** a huge amount of legacy SQL that uses it. So for now, we just
      ** issue a warning.
      */
      sqlite3_log(SQLITE_WARNING,
        "double-quoted string literal: \"%w\"", zCol);
#ifdef SQLITE_ENABLE_NORMALIZE
      sqlite3VdbeAddDblquoteStr(db, pParse->pVdbe, zCol);
#endif
      pExpr->op = TK_STRING;
      pExpr->y.pTab = 0;
      return WRC_Prune;
    }
    if( sqlite3ExprIdToTrueFalse(pExpr) ){
      return WRC_Prune;

Changes to src/sqlite.h.in.

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** and [sqlite3_prepare16_v3()] assume that the prepared statement will 
** be used just once or at most a few times and then destroyed using
** [sqlite3_finalize()] relatively soon. The current implementation acts
** on this hint by avoiding the use of [lookaside memory] so as not to
** deplete the limited store of lookaside memory. Future versions of
** SQLite may act on this hint differently.
**
** [[SQLITE_PREPARE_NORMALIZE]] ^(<dt>SQLITE_PREPARE_NORMALIZE</dt>
** <dd>The SQLITE_PREPARE_NORMALIZE flag indicates that a normalized
** representation of the SQL statement should be calculated and then
** associated with the prepared statement, which can be obtained via
** the [sqlite3_normalized_sql()] interface.)^  The semantics used to

** normalize a SQL statement are unspecified and subject to change.
** At a minimum, literal values will be replaced with suitable
** placeholders.
** </dl>
*/
#define SQLITE_PREPARE_PERSISTENT              0x01
#define SQLITE_PREPARE_NORMALIZE               0x02

/*
** CAPI3REF: Compiling An SQL Statement







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** and [sqlite3_prepare16_v3()] assume that the prepared statement will 
** be used just once or at most a few times and then destroyed using
** [sqlite3_finalize()] relatively soon. The current implementation acts
** on this hint by avoiding the use of [lookaside memory] so as not to
** deplete the limited store of lookaside memory. Future versions of
** SQLite may act on this hint differently.
**
** [[SQLITE_PREPARE_NORMALIZE]] <dt>SQLITE_PREPARE_NORMALIZE</dt>
** <dd>The SQLITE_PREPARE_NORMALIZE flag is a no-op. This flag used
** to be required for any prepared statement that wanted to use the

** [sqlite3_normalized_sql()] interface.  However, the
** [sqlite3_normalized_sql()] interface is now available to all
** prepared statements, regardless of whether or not they use this
** flag.

** </dl>
*/
#define SQLITE_PREPARE_PERSISTENT              0x01
#define SQLITE_PREPARE_NORMALIZE               0x02

/*
** CAPI3REF: Compiling An SQL Statement

Changes to src/sqliteInt.h.

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int sqlite3VtabBegin(sqlite3 *, VTable *);
FuncDef *sqlite3VtabOverloadFunction(sqlite3 *,FuncDef*, int nArg, Expr*);
sqlite3_int64 sqlite3StmtCurrentTime(sqlite3_context*);
int sqlite3VdbeParameterIndex(Vdbe*, const char*, int);
int sqlite3TransferBindings(sqlite3_stmt *, sqlite3_stmt *);
void sqlite3ParserReset(Parse*);
#ifdef SQLITE_ENABLE_NORMALIZE
char *sqlite3Normalize(Vdbe*, const char*, int);
#endif
int sqlite3Reprepare(Vdbe*);
void sqlite3ExprListCheckLength(Parse*, ExprList*, const char*);
CollSeq *sqlite3BinaryCompareCollSeq(Parse *, Expr *, Expr *);
int sqlite3TempInMemory(const sqlite3*);
const char *sqlite3JournalModename(int);
#ifndef SQLITE_OMIT_WAL







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int sqlite3VtabBegin(sqlite3 *, VTable *);
FuncDef *sqlite3VtabOverloadFunction(sqlite3 *,FuncDef*, int nArg, Expr*);
sqlite3_int64 sqlite3StmtCurrentTime(sqlite3_context*);
int sqlite3VdbeParameterIndex(Vdbe*, const char*, int);
int sqlite3TransferBindings(sqlite3_stmt *, sqlite3_stmt *);
void sqlite3ParserReset(Parse*);
#ifdef SQLITE_ENABLE_NORMALIZE
char *sqlite3Normalize(Vdbe*, const char*);
#endif
int sqlite3Reprepare(Vdbe*);
void sqlite3ExprListCheckLength(Parse*, ExprList*, const char*);
CollSeq *sqlite3BinaryCompareCollSeq(Parse *, Expr *, Expr *);
int sqlite3TempInMemory(const sqlite3*);
const char *sqlite3JournalModename(int);
#ifndef SQLITE_OMIT_WAL

Changes to src/tokenize.c.

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/*
** Compute a normalization of the SQL given by zSql[0..nSql-1].  Return
** the normalization in space obtained from sqlite3DbMalloc().  Or return
** NULL if anything goes wrong or if zSql is NULL.
*/
char *sqlite3Normalize(
  Vdbe *pVdbe,       /* VM being reprepared */
  const char *zSql,  /* The original SQL string */
  int nSql           /* Size of the input string in bytes */
){
  sqlite3 *db;       /* The database connection */
  int i;             /* Next unread byte of zSql[] */
  int n;             /* length of current token */
  int tokenType;     /* type of current token */
  int prevType;      /* Previous non-whitespace token */
  int nParen;        /* Number of nested levels of parentheses */
  int iStartIN;      /* Start of RHS of IN operator in z[] */
  int nParenAtIN;    /* Value of nParent at start of RHS of IN operator */
  int j;             /* Bytes of normalized SQL generated so far */
  sqlite3_str *pStr; /* The normalized SQL string under construction */

  if( zSql==0 || nSql==0 ) return 0;
  db = sqlite3VdbeDb(pVdbe);
  tokenType = -1;
  nParen = iStartIN = nParenAtIN = 0;
  pStr = sqlite3_str_new(db);

  for(i=0; i<nSql && pStr->accError==0; i+=n){
    if( tokenType!=TK_SPACE ){
      prevType = tokenType;
    }
    n = sqlite3GetToken((unsigned char*)zSql+i, &tokenType);
    if( NEVER(n<=0) ) break;
    switch( tokenType ){
      case TK_SPACE: {







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/*
** Compute a normalization of the SQL given by zSql[0..nSql-1].  Return
** the normalization in space obtained from sqlite3DbMalloc().  Or return
** NULL if anything goes wrong or if zSql is NULL.
*/
char *sqlite3Normalize(
  Vdbe *pVdbe,       /* VM being reprepared */
  const char *zSql   /* The original SQL string */

){
  sqlite3 *db;       /* The database connection */
  int i;             /* Next unread byte of zSql[] */
  int n;             /* length of current token */
  int tokenType;     /* type of current token */
  int prevType;      /* Previous non-whitespace token */
  int nParen;        /* Number of nested levels of parentheses */
  int iStartIN;      /* Start of RHS of IN operator in z[] */
  int nParenAtIN;    /* Value of nParent at start of RHS of IN operator */
  int j;             /* Bytes of normalized SQL generated so far */
  sqlite3_str *pStr; /* The normalized SQL string under construction */


  db = sqlite3VdbeDb(pVdbe);
  tokenType = -1;
  nParen = iStartIN = nParenAtIN = 0;
  pStr = sqlite3_str_new(db);
  assert( pStr!=0 );  /* sqlite3_str_new() never returns NULL */
  for(i=0; zSql[i] && pStr->accError==0; i+=n){
    if( tokenType!=TK_SPACE ){
      prevType = tokenType;
    }
    n = sqlite3GetToken((unsigned char*)zSql+i, &tokenType);
    if( NEVER(n<=0) ) break;
    switch( tokenType ){
      case TK_SPACE: {

Changes to src/vdbeapi.c.

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#ifdef SQLITE_ENABLE_NORMALIZE
/*
** Return the normalized SQL associated with a prepared statement.
*/
const char *sqlite3_normalized_sql(sqlite3_stmt *pStmt){
  Vdbe *p = (Vdbe *)pStmt;
  if( p==0 ) return 0;
  if( p->zNormSql==0 && p->zSql!=0 ){
    sqlite3_mutex_enter(p->db->mutex);
    p->zNormSql = sqlite3Normalize(p, p->zSql, sqlite3Strlen30(p->zSql));
    sqlite3_mutex_leave(p->db->mutex);
  }
  return p->zNormSql;
}
#endif /* SQLITE_ENABLE_NORMALIZE */

#ifdef SQLITE_ENABLE_PREUPDATE_HOOK







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#ifdef SQLITE_ENABLE_NORMALIZE
/*
** Return the normalized SQL associated with a prepared statement.
*/
const char *sqlite3_normalized_sql(sqlite3_stmt *pStmt){
  Vdbe *p = (Vdbe *)pStmt;
  if( p==0 ) return 0;
  if( p->zNormSql==0 && ALWAYS(p->zSql!=0) ){
    sqlite3_mutex_enter(p->db->mutex);
    p->zNormSql = sqlite3Normalize(p, p->zSql);
    sqlite3_mutex_leave(p->db->mutex);
  }
  return p->zNormSql;
}
#endif /* SQLITE_ENABLE_NORMALIZE */

#ifdef SQLITE_ENABLE_PREUPDATE_HOOK

Changes to src/vdbeaux.c.

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  if( p==0 ) return;
  p->prepFlags = prepFlags;
  if( (prepFlags & SQLITE_PREPARE_SAVESQL)==0 ){
    p->expmask = 0;
  }
  assert( p->zSql==0 );
  p->zSql = sqlite3DbStrNDup(p->db, z, n);
#ifdef SQLITE_ENABLE_NORMALIZE
  assert( p->zNormSql==0 );
  if( p->zSql && (prepFlags & SQLITE_PREPARE_NORMALIZE)!=0 ){
    p->zNormSql = sqlite3Normalize(p, p->zSql, n);
    assert( p->zNormSql!=0 || p->db->mallocFailed );
  }
#endif
}

#ifdef SQLITE_ENABLE_NORMALIZE
/*
** Add a new element to the Vdbe->pDblStr list.
*/
void sqlite3VdbeAddDblquoteStr(sqlite3 *db, Vdbe *p, const char *z){







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  if( p==0 ) return;
  p->prepFlags = prepFlags;
  if( (prepFlags & SQLITE_PREPARE_SAVESQL)==0 ){
    p->expmask = 0;
  }
  assert( p->zSql==0 );
  p->zSql = sqlite3DbStrNDup(p->db, z, n);







}

#ifdef SQLITE_ENABLE_NORMALIZE
/*
** Add a new element to the Vdbe->pDblStr list.
*/
void sqlite3VdbeAddDblquoteStr(sqlite3 *db, Vdbe *p, const char *z){