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Overview
Comment: | Simplify the code used to generate the text for EXPLAIN QUERY PLAN. |
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Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | trunk |
Files: | files | file ages | folders |
SHA1: |
beea1efc3a49cad08087fcbb18dbce71 |
User & Date: | drh 2014-10-10 15:47:46.266 |
Context
2014-10-10
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17:20 | Add the estimated number of output rows to the EXPLAIN QUERY PLAN output if compiled with SQLITE_EXPLAIN_ESTIMATED_ROWS. This feature is off by default for the time being. (check-in: daa8314fba user: drh tags: trunk) | |
15:47 | Simplify the code used to generate the text for EXPLAIN QUERY PLAN. (check-in: beea1efc3a user: drh tags: trunk) | |
15:01 | Fix a potential problem in the whereRangeScanEst() routine when STAT4 is active. The problem was introduced by recent enhancements. (check-in: 68e1b4de70 user: drh tags: trunk) | |
Changes
Changes to src/where.c.
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2733 2734 2735 2736 2737 2738 2739 | sqlite3StrAccumAppendAll(pStr, zColumn); sqlite3StrAccumAppend(pStr, zOp, 1); sqlite3StrAccumAppend(pStr, "?", 1); } /* ** Argument pLevel describes a strategy for scanning table pTab. This | | | < < < < < | < | < < < < | | | < | < | | | < | 2733 2734 2735 2736 2737 2738 2739 2740 2741 2742 2743 2744 2745 2746 2747 2748 2749 2750 2751 2752 2753 2754 2755 2756 2757 2758 2759 2760 2761 2762 2763 2764 2765 2766 2767 2768 2769 2770 2771 2772 2773 2774 2775 2776 2777 2778 2779 2780 2781 2782 2783 2784 2785 2786 2787 2788 | sqlite3StrAccumAppendAll(pStr, zColumn); sqlite3StrAccumAppend(pStr, zOp, 1); sqlite3StrAccumAppend(pStr, "?", 1); } /* ** Argument pLevel describes a strategy for scanning table pTab. This ** function appends text to pStr that describes the subset of table ** rows scanned by the strategy in the form of an SQL expression. ** ** For example, if the query: ** ** SELECT * FROM t1 WHERE a=1 AND b>2; ** ** is run and there is an index on (a, b), then this function returns a ** string similar to: ** ** "a=? AND b>?" */ void explainIndexRange(StrAccum *pStr, WhereLoop *pLoop, Table *pTab){ Index *pIndex = pLoop->u.btree.pIndex; u16 nEq = pLoop->u.btree.nEq; u16 nSkip = pLoop->u.btree.nSkip; int i, j; Column *aCol = pTab->aCol; i16 *aiColumn = pIndex->aiColumn; if( nEq==0 && (pLoop->wsFlags&(WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))==0 ) return; sqlite3StrAccumAppend(pStr, " (", 2); for(i=0; i<nEq; i++){ char *z = aiColumn[i] < 0 ? "rowid" : aCol[aiColumn[i]].zName; if( i>=nSkip ){ explainAppendTerm(pStr, i, z, "="); }else{ if( i ) sqlite3StrAccumAppend(pStr, " AND ", 5); sqlite3XPrintf(pStr, 0, "ANY(%s)", z); } } j = i; if( pLoop->wsFlags&WHERE_BTM_LIMIT ){ char *z = aiColumn[j] < 0 ? "rowid" : aCol[aiColumn[j]].zName; explainAppendTerm(pStr, i++, z, ">"); } if( pLoop->wsFlags&WHERE_TOP_LIMIT ){ char *z = aiColumn[j] < 0 ? "rowid" : aCol[aiColumn[j]].zName; explainAppendTerm(pStr, i, z, "<"); } sqlite3StrAccumAppend(pStr, ")", 1); } /* ** This function is a no-op unless currently processing an EXPLAIN QUERY PLAN ** command. If the query being compiled is an EXPLAIN QUERY PLAN, a single ** record is added to the output to describe the table scan strategy in ** pLevel. |
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2811 2812 2813 2814 2815 2816 2817 | #ifndef SQLITE_DEBUG if( pParse->explain==2 ) #endif { struct SrcList_item *pItem = &pTabList->a[pLevel->iFrom]; Vdbe *v = pParse->pVdbe; /* VM being constructed */ sqlite3 *db = pParse->db; /* Database handle */ | < > > > > > | | | | | < < | | | > > > > > | > | | | | | > > > < | | | | > | | > > | | | 2798 2799 2800 2801 2802 2803 2804 2805 2806 2807 2808 2809 2810 2811 2812 2813 2814 2815 2816 2817 2818 2819 2820 2821 2822 2823 2824 2825 2826 2827 2828 2829 2830 2831 2832 2833 2834 2835 2836 2837 2838 2839 2840 2841 2842 2843 2844 2845 2846 2847 2848 2849 2850 2851 2852 2853 2854 2855 2856 2857 2858 2859 2860 2861 2862 2863 2864 2865 2866 2867 2868 2869 2870 2871 2872 2873 2874 2875 2876 2877 2878 2879 2880 2881 2882 2883 2884 2885 2886 | #ifndef SQLITE_DEBUG if( pParse->explain==2 ) #endif { struct SrcList_item *pItem = &pTabList->a[pLevel->iFrom]; Vdbe *v = pParse->pVdbe; /* VM being constructed */ sqlite3 *db = pParse->db; /* Database handle */ int iId = pParse->iSelectId; /* Select id (left-most output column) */ int isSearch; /* True for a SEARCH. False for SCAN. */ WhereLoop *pLoop; /* The controlling WhereLoop object */ u32 flags; /* Flags that describe this loop */ char *zMsg; /* Text to add to EQP output */ StrAccum str; /* EQP output string */ char zBuf[100]; /* Initial space for EQP output string */ pLoop = pLevel->pWLoop; flags = pLoop->wsFlags; if( (flags&WHERE_MULTI_OR) || (wctrlFlags&WHERE_ONETABLE_ONLY) ) return; isSearch = (flags&(WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))!=0 || ((flags&WHERE_VIRTUALTABLE)==0 && (pLoop->u.btree.nEq>0)) || (wctrlFlags&(WHERE_ORDERBY_MIN|WHERE_ORDERBY_MAX)); sqlite3StrAccumInit(&str, zBuf, sizeof(zBuf), SQLITE_MAX_LENGTH); str.db = db; sqlite3StrAccumAppendAll(&str, isSearch ? "SEARCH" : "SCAN"); if( pItem->pSelect ){ sqlite3XPrintf(&str, 0, " SUBQUERY %d", pItem->iSelectId); }else{ sqlite3XPrintf(&str, 0, " TABLE %s", pItem->zName); } if( pItem->zAlias ){ sqlite3XPrintf(&str, 0, " AS %s", pItem->zAlias); } if( (flags & (WHERE_IPK|WHERE_VIRTUALTABLE))==0 ){ const char *zFmt = 0; Index *pIdx; assert( pLoop->u.btree.pIndex!=0 ); pIdx = pLoop->u.btree.pIndex; assert( !(flags&WHERE_AUTO_INDEX) || (flags&WHERE_IDX_ONLY) ); if( !HasRowid(pItem->pTab) && IsPrimaryKeyIndex(pIdx) ){ if( pLoop->u.btree.nEq>0 || (pLoop->wsFlags & (WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))!=0 ){ zFmt = "PRIMARY KEY"; } }else if( flags & WHERE_AUTO_INDEX ){ zFmt = "AUTOMATIC COVERING INDEX"; }else if( flags & WHERE_IDX_ONLY ){ zFmt = "COVERING INDEX %s"; }else{ zFmt = "INDEX %s"; } if( zFmt ){ sqlite3StrAccumAppend(&str, " USING ", 7); sqlite3XPrintf(&str, 0, zFmt, pIdx->zName); explainIndexRange(&str, pLoop, pItem->pTab); } }else if( (flags & WHERE_IPK)!=0 && (flags & WHERE_CONSTRAINT)!=0 ){ const char *zRange; if( flags&(WHERE_COLUMN_EQ|WHERE_COLUMN_IN) ){ zRange = "(rowid=?)"; }else if( (flags&WHERE_BOTH_LIMIT)==WHERE_BOTH_LIMIT ){ zRange = "(rowid>? AND rowid<?)"; }else if( flags&WHERE_BTM_LIMIT ){ zRange = "(rowid>?)"; }else{ assert( flags&WHERE_TOP_LIMIT); zRange = "(rowid<?)"; } sqlite3StrAccumAppendAll(&str, " USING INTEGER PRIMARY KEY "); sqlite3StrAccumAppendAll(&str, zRange); } #ifndef SQLITE_OMIT_VIRTUALTABLE else if( (flags & WHERE_VIRTUALTABLE)!=0 ){ sqlite3XPrintf(&str, 0, " VIRTUAL TABLE INDEX %d:%s", pLoop->u.vtab.idxNum, pLoop->u.vtab.idxStr); } #endif zMsg = sqlite3StrAccumFinish(&str); sqlite3VdbeAddOp4(v, OP_Explain, iId, iLevel, iFrom, zMsg, P4_DYNAMIC); } } #else # define explainOneScan(u,v,w,x,y,z) #endif /* SQLITE_OMIT_EXPLAIN */ |
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