SQLite: Check-in [3c1ae447]

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Overview

Comment:	Reduce the number of cases where it is necessary to check for NULL after the loop terminating condition.
Downloads:	Tarball \| ZIP archive \| SQL archive
Timelines:	family \| ancestors \| descendants \| both \| trunk
Files:	files \| file ages \| folders
SHA1:	3c1ae447dec8fc2af1c5105134061717594ac0e0
User & Date:	drh 2014-02-14 20:59:53

Context

2014-02-14
23:49		Seek past NULLs in a top-constrained search. Avoid checking for NULLs in the body of the search. (check-in: e07a32f3 user: drh tags: trunk)
23:35		Better support for MinGW 4.x. (check-in: e1472307 user: mistachkin tags: mingw4x)
20:59		Reduce the number of cases where it is necessary to check for NULL after the loop terminating condition. (check-in: 3c1ae447 user: drh tags: trunk)
15:13		Add OP_IdxGT and OP_IdxLE as distinct opcodes. Formerly these operations where done using OP_IdxGE and OP_IdxLT with the P5 flag set. But VDBE code is easier to read with distinct opcode names. Also change OP_SeekGe to OP_SeekGE, and so forth, so that the capitalization is consistent. The whole point of this change is to improve the readability of VDBE listings. (check-in: b6bea903 user: drh tags: trunk)

Changes

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Changes to src/where.c.

  3130   3130         testcase( op==OP_IdxGT );
  3131   3131         testcase( op==OP_IdxGE );
  3132   3132         testcase( op==OP_IdxLT );
  3133   3133         testcase( op==OP_IdxLE );
  3134   3134         sqlite3VdbeAddOp4Int(v, op, iIdxCur, addrNxt, regBase, nConstraint);
  3135   3135       }
  3136   3136   
  3137         -    /* If there are inequality constraints, check that the value
  3138         -    ** of the table column that the inequality contrains is not NULL.
  3139         -    ** If it is, jump to the next iteration of the loop.
         3137  +    /* If there are inequality constraint upper bound but not a lower
         3138  +    ** bound, then check that the value of the table column that the
         3139  +    ** inequality contrains is not NULL since there is alway an implied
         3140  +    ** lower bound of "column>NULL".
  3140   3141       */
  3141   3142       r1 = sqlite3GetTempReg(pParse);
  3142         -    testcase( pLoop->wsFlags & WHERE_BTM_LIMIT );
  3143         -    testcase( pLoop->wsFlags & WHERE_TOP_LIMIT );
  3144         -    if( (pLoop->wsFlags & (WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))!=0 
         3143  +    if( (pLoop->wsFlags & (WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))==WHERE_TOP_LIMIT 
  3145   3144        && (j = pIdx->aiColumn[nEq])>=0 
  3146   3145        && pIdx->pTable->aCol[j].notNull==0 
  3147         -     && (nEq || (pLoop->wsFlags & WHERE_BTM_LIMIT)==0)
  3148   3146       ){
  3149   3147         sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, nEq, r1);
  3150   3148         VdbeComment((v, "%s", pIdx->pTable->aCol[j].zName));
  3151   3149         sqlite3VdbeAddOp2(v, OP_IsNull, r1, addrCont);
  3152   3150       }
  3153   3151       sqlite3ReleaseTempReg(pParse, r1);
  3154   3152