SQLite

Check-in [48f40861db]
Login

Many hyperlinks are disabled.
Use anonymous login to enable hyperlinks.

Overview
Comment:When running ANALYZE, it is not necessary to check the right-most key column for changes since that column will always change if none of the previous columns have.
Downloads: Tarball | ZIP archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA1: 48f40861db4fbd10725a2b8b606d44fe16d5bd27
User & Date: drh 2014-07-22 22:46:54.689
Context
2014-07-23
15:51
Updated documentation on sqlite3_temp_directory. No changes to code. (check-in: e6225a7bf7 user: drh tags: trunk)
01:26
Add support for parsing C-style hexadecimal literals. (check-in: 34a1f38b7a user: drh tags: hex-literal)
2014-07-22
22:46
When running ANALYZE, it is not necessary to check the right-most key column for changes since that column will always change if none of the previous columns have. (check-in: 48f40861db user: drh tags: trunk)
20:02
Add the OP_ReopenIdx opcode that works like OP_OpenRead except that it becomes a no-op if the cursor is already open on the same index. Update the OR-optimization logic to make use of OP_ReopenIdx in order to avoid unnecessary cursor open requests sent to the B-Tree layer. (check-in: 77f412caf0 user: drh tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/analyze.c.
︙︙
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139

    **   regChng = 1
    **   if( idx(1) != regPrev(1) ) goto chng_addr_1
    **   ...
    **   regChng = N
    **   goto chng_addr_N
    */
    addrNextRow = sqlite3VdbeCurrentAddr(v);
    for(i=0; i<nCol; i++){
      char *pColl = (char*)sqlite3LocateCollSeq(pParse, pIdx->azColl[i]);
      sqlite3VdbeAddOp2(v, OP_Integer, i, regChng);
      sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, i, regTemp);
      aGotoChng[i] = 
      sqlite3VdbeAddOp4(v, OP_Ne, regTemp, 0, regPrev+i, pColl, P4_COLLSEQ);
      sqlite3VdbeChangeP5(v, SQLITE_NULLEQ);
      VdbeCoverage(v);
    }
    sqlite3VdbeAddOp2(v, OP_Integer, nCol, regChng);
    aGotoChng[nCol] = sqlite3VdbeAddOp0(v, OP_Goto);

    /*
    **  chng_addr_0:
    **   regPrev(0) = idx(0)
    **  chng_addr_1:
    **   regPrev(1) = idx(1)
    **  ...
    */
    sqlite3VdbeJumpHere(v, addrGotoChng0);
    for(i=0; i<nCol; i++){
      sqlite3VdbeJumpHere(v, aGotoChng[i]);
      sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, i, regPrev+i);
    }

    /*
    **  chng_addr_N:
    **   regRowid = idx(rowid)            // STAT34 only








|








|










|








1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139

    **   regChng = 1
    **   if( idx(1) != regPrev(1) ) goto chng_addr_1
    **   ...
    **   regChng = N
    **   goto chng_addr_N
    */
    addrNextRow = sqlite3VdbeCurrentAddr(v);
    for(i=0; i<nCol-1; i++){
      char *pColl = (char*)sqlite3LocateCollSeq(pParse, pIdx->azColl[i]);
      sqlite3VdbeAddOp2(v, OP_Integer, i, regChng);
      sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, i, regTemp);
      aGotoChng[i] = 
      sqlite3VdbeAddOp4(v, OP_Ne, regTemp, 0, regPrev+i, pColl, P4_COLLSEQ);
      sqlite3VdbeChangeP5(v, SQLITE_NULLEQ);
      VdbeCoverage(v);
    }
    sqlite3VdbeAddOp2(v, OP_Integer, nCol-1, regChng);
    aGotoChng[nCol] = sqlite3VdbeAddOp0(v, OP_Goto);

    /*
    **  chng_addr_0:
    **   regPrev(0) = idx(0)
    **  chng_addr_1:
    **   regPrev(1) = idx(1)
    **  ...
    */
    sqlite3VdbeJumpHere(v, addrGotoChng0);
    for(i=0; i<nCol-1; i++){
      sqlite3VdbeJumpHere(v, aGotoChng[i]);
      sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, i, regPrev+i);
    }

    /*
    **  chng_addr_N:
    **   regRowid = idx(rowid)            // STAT34 only
︙︙