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Overview
Comment:Unroll the comparison loop inside keywordCode() for to avoid unnecessary comparisions and thus help that routine run faster.
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SHA3-256: cec5f920f5c2a963f88329a08a443fc04be2dd6f7f2d840be63c0ab1de898f0a
User & Date: drh 2020-02-06 15:38:43
Context
2020-02-06
20:46
There is no need to keep track of the number of changed rows or of the last-insert-rowid while running VACUUM. (check-in: a8a7c05b user: drh tags: trunk)
15:38
Unroll the comparison loop inside keywordCode() for to avoid unnecessary comparisions and thus help that routine run faster. (check-in: cec5f920 user: drh tags: trunk)
13:57
Separate OP_IdxInsert and OP_SorterInsert into completely separate opcodes, helping each one to run a little faster. (check-in: 447d71f0 user: drh tags: trunk)
Changes
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Changes to tool/mkkeywordhash.c.

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  printf("  int i, j;\n");
  printf("  const char *zKW;\n");
  printf("  if( n>=2 ){\n");
  printf("    i = ((charMap(z[0])*4) ^ (charMap(z[n-1])*3) ^ n) %% %d;\n",
          bestSize);
  printf("    for(i=((int)aKWHash[i])-1; i>=0; i=((int)aKWNext[i])-1){\n");
  printf("      if( aKWLen[i]!=n ) continue;\n");
  printf("      j = 0;\n");
  printf("      zKW = &zKWText[aKWOffset[i]];\n");
  printf("#ifdef SQLITE_ASCII\n");



  printf("      while( j<n && (z[j]&~0x20)==zKW[j] ){ j++; }\n");
  printf("#endif\n");
  printf("#ifdef SQLITE_EBCDIC\n");



  printf("      while( j<n && toupper(z[j])==zKW[j] ){ j++; }\n");
  printf("#endif\n");
  printf("      if( j<n ) continue;\n");
  for(i=0; i<nKeyword; i++){
    printf("      testcase( i==%d ); /* %s */\n",
           i, aKeywordTable[i].zOrigName);
  }







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  printf("  int i, j;\n");
  printf("  const char *zKW;\n");
  printf("  if( n>=2 ){\n");
  printf("    i = ((charMap(z[0])*4) ^ (charMap(z[n-1])*3) ^ n) %% %d;\n",
          bestSize);
  printf("    for(i=((int)aKWHash[i])-1; i>=0; i=((int)aKWNext[i])-1){\n");
  printf("      if( aKWLen[i]!=n ) continue;\n");

  printf("      zKW = &zKWText[aKWOffset[i]];\n");
  printf("#ifdef SQLITE_ASCII\n");
  printf("      if( (z[0]&~0x20)!=zKW[0] ) continue;\n");
  printf("      if( (z[1]&~0x20)!=zKW[1] ) continue;\n");
  printf("      j = 2;\n");
  printf("      while( j<n && (z[j]&~0x20)==zKW[j] ){ j++; }\n");
  printf("#endif\n");
  printf("#ifdef SQLITE_EBCDIC\n");
  printf("      if( toupper(z[0])!=zKW[0] ) continue;\n");
  printf("      if( toupper(z[1])!=zKW[1] ) continue;\n");
  printf("      j = 2;\n");
  printf("      while( j<n && toupper(z[j])==zKW[j] ){ j++; }\n");
  printf("#endif\n");
  printf("      if( j<n ) continue;\n");
  for(i=0; i<nKeyword; i++){
    printf("      testcase( i==%d ); /* %s */\n",
           i, aKeywordTable[i].zOrigName);
  }