|
| 1 | +/*------------------------------------------------------------------------- |
| 2 | + * |
| 3 | + * prepkeyset.c-- |
| 4 | + * Special preperation for keyset queries. |
| 5 | + * |
| 6 | + * Copyright (c) 1994, Regents of the University of California |
| 7 | + * |
| 8 | + *------------------------------------------------------------------------- |
| 9 | + */ |
| 10 | +#include<stdio.h> |
| 11 | +#include<string.h> |
| 12 | + |
| 13 | +#include"postgres.h" |
| 14 | +#include"nodes/pg_list.h" |
| 15 | +#include"nodes/parsenodes.h" |
| 16 | +#include"utils/elog.h" |
| 17 | + |
| 18 | +#include"nodes/nodes.h" |
| 19 | +#include"nodes/execnodes.h" |
| 20 | +#include"nodes/plannodes.h" |
| 21 | +#include"nodes/primnodes.h" |
| 22 | +#include"nodes/relation.h" |
| 23 | + |
| 24 | +#include"catalog/pg_type.h" |
| 25 | +#include"lib/stringinfo.h" |
| 26 | +#include"optimizer/planmain.h" |
| 27 | +/* |
| 28 | + * Node_Copy-- |
| 29 | + * a macro to simplify calling of copyObject on the specified field |
| 30 | + */ |
| 31 | +#defineNode_Copy(from,newnode,field) newnode->field = copyObject(from->field) |
| 32 | + |
| 33 | +/***** DEBUG stuff |
| 34 | +#define TABS {int i; printf("\n"); for (i = 0; i<level; i++) printf("\t"); } |
| 35 | +static int level = 0; |
| 36 | +******/ |
| 37 | + |
| 38 | +bool_use_keyset_query_optimizer= FALSE; |
| 39 | + |
| 40 | +staticintinspectOpNode(Expr*expr); |
| 41 | +staticintinspectAndNode(Expr*expr); |
| 42 | +staticintinspectOrNode(Expr*expr); |
| 43 | + |
| 44 | +/********************************************************************** |
| 45 | + * This routine transforms query trees with the following form: |
| 46 | + * SELECT a,b, ... FROM one_table WHERE |
| 47 | + * (v1 = const1 AND v2 = const2 [ vn = constn ]) OR |
| 48 | + * (v1 = const3 AND v2 = const4 [ vn = constn ]) OR |
| 49 | + * (v1 = const5 AND v2 = const6 [ vn = constn ]) OR |
| 50 | + * ... |
| 51 | + * [(v1 = constn AND v2 = constn [ vn = constn ])] |
| 52 | + * |
| 53 | + * into |
| 54 | + * |
| 55 | + * SELECT a,b, ... FROM one_table WHERE |
| 56 | + * (v1 = const1 AND v2 = const2 [ vn = constn ]) UNION |
| 57 | + * SELECT a,b, ... FROM one_table WHERE |
| 58 | + * (v1 = const3 AND v2 = const4 [ vn = constn ]) UNION |
| 59 | + * SELECT a,b, ... FROM one_table WHERE |
| 60 | + * (v1 = const5 AND v2 = const6 [ vn = constn ]) UNION |
| 61 | + * ... |
| 62 | + * SELECT a,b, ... FROM one_table WHERE |
| 63 | + * [(v1 = constn AND v2 = constn [ vn = constn ])] |
| 64 | + * |
| 65 | + * |
| 66 | + * To qualify for transformation the query must not be a sub select, |
| 67 | + * a HAVING, or a GROUP BY. It must be a single table and have KSQO |
| 68 | + * set to 'on'. |
| 69 | + * |
| 70 | + * The primary use of this transformation is to avoid the exponrntial |
| 71 | + * memory consumption of cnfify() and to make use of index access |
| 72 | + * methods. |
| 73 | + * |
| 74 | + * daveh@insightdist.com 1998-08-31 |
| 75 | + * |
| 76 | + * Needs to better identify the signeture WHERE clause. |
| 77 | + * May want to also prune out duplicate where clauses. |
| 78 | + **********************************************************************/ |
| 79 | +void |
| 80 | +transformKeySetQuery(Query*origNode) |
| 81 | +{ |
| 82 | +/* Qualify as a key set query candidate */ |
| 83 | +if (_use_keyset_query_optimizer== FALSE|| |
| 84 | +origNode->groupClause|| |
| 85 | +origNode->havingQual|| |
| 86 | +origNode->hasAggs|| |
| 87 | +origNode->utilityStmt|| |
| 88 | +origNode->unionClause|| |
| 89 | +origNode->unionall|| |
| 90 | +origNode->hasSubLinks|| |
| 91 | +origNode->commandType!=CMD_SELECT) |
| 92 | +return; |
| 93 | + |
| 94 | +/* Qualify single table query */ |
| 95 | + |
| 96 | +/* Qualify where clause */ |
| 97 | +if ( !inspectOrNode((Expr*)origNode->qual)) { |
| 98 | +return; |
| 99 | +} |
| 100 | + |
| 101 | +/* Copy essential elements into a union node */ |
| 102 | +/* |
| 103 | +elog(NOTICE, "OR_EXPR=%d, OP_EXPR=%d, AND_EXPR=%d", OR_EXPR, OP_EXPR, AND_EXPR); |
| 104 | +elog(NOTICE, "T_List=%d, T_Expr=%d, T_Var=%d, T_Const=%d", T_List, T_Expr, T_Var, T_Const); |
| 105 | +elog(NOTICE, "opType=%d", ((Expr*)origNode->qual)->opType); |
| 106 | +*/ |
| 107 | +while (((Expr*)origNode->qual)->opType==OR_EXPR) { |
| 108 | +Query*unionNode=makeNode(Query); |
| 109 | + |
| 110 | +/* Pull up Expr = */ |
| 111 | +unionNode->qual=lsecond(((Expr*)origNode->qual)->args); |
| 112 | + |
| 113 | +/* Pull up balance of tree */ |
| 114 | +origNode->qual=lfirst(((Expr*)origNode->qual)->args); |
| 115 | + |
| 116 | +/* |
| 117 | +elog(NOTICE, "origNode: opType=%d, nodeTag=%d", ((Expr*)origNode->qual)->opType, nodeTag(origNode->qual)); |
| 118 | +elog(NOTICE, "unionNode: opType=%d, nodeTag=%d", ((Expr*)unionNode->qual)->opType, nodeTag(unionNode->qual)); |
| 119 | +*/ |
| 120 | + |
| 121 | +unionNode->commandType=origNode->commandType; |
| 122 | +unionNode->resultRelation=origNode->resultRelation; |
| 123 | +unionNode->isPortal=origNode->isPortal; |
| 124 | +unionNode->isBinary=origNode->isBinary; |
| 125 | + |
| 126 | +if (origNode->uniqueFlag) |
| 127 | +unionNode->uniqueFlag=pstrdup(origNode->uniqueFlag); |
| 128 | + |
| 129 | +Node_Copy(origNode,unionNode,sortClause); |
| 130 | +Node_Copy(origNode,unionNode,rtable); |
| 131 | +Node_Copy(origNode,unionNode,targetList); |
| 132 | + |
| 133 | +origNode->unionClause=lappend(origNode->unionClause,unionNode); |
| 134 | +} |
| 135 | +return; |
| 136 | +} |
| 137 | + |
| 138 | + |
| 139 | + |
| 140 | + |
| 141 | +staticint |
| 142 | +inspectOrNode(Expr*expr) |
| 143 | +{ |
| 144 | +intfr=0,sr=0; |
| 145 | +Expr*firstExpr,*secondExpr; |
| 146 | + |
| 147 | +if ( ! (expr&&nodeTag(expr)==T_Expr&&expr->opType==OR_EXPR)) |
| 148 | +return0; |
| 149 | + |
| 150 | +firstExpr=lfirst(expr->args); |
| 151 | +secondExpr=lsecond(expr->args); |
| 152 | +if (nodeTag(firstExpr)!=T_Expr||nodeTag(secondExpr)!=T_Expr) |
| 153 | +return0; |
| 154 | + |
| 155 | +if (firstExpr->opType==OR_EXPR) |
| 156 | +fr=inspectOrNode(firstExpr); |
| 157 | +elseif (firstExpr->opType==OP_EXPR)/* Need to make sure it is last */ |
| 158 | +fr=inspectOpNode(firstExpr); |
| 159 | +elseif (firstExpr->opType==AND_EXPR)/* Need to make sure it is last */ |
| 160 | +fr=inspectAndNode(firstExpr); |
| 161 | + |
| 162 | + |
| 163 | +if (secondExpr->opType==AND_EXPR) |
| 164 | +sr=inspectAndNode(secondExpr); |
| 165 | +elseif (secondExpr->opType==OP_EXPR) |
| 166 | +sr=inspectOpNode(secondExpr); |
| 167 | + |
| 168 | +return (fr&&sr); |
| 169 | +} |
| 170 | + |
| 171 | + |
| 172 | +staticint |
| 173 | +inspectAndNode(Expr*expr) |
| 174 | +{ |
| 175 | +intfr=0,sr=0; |
| 176 | +Expr*firstExpr,*secondExpr; |
| 177 | + |
| 178 | +if ( ! (expr&&nodeTag(expr)==T_Expr&&expr->opType==AND_EXPR)) |
| 179 | +return0; |
| 180 | + |
| 181 | +firstExpr=lfirst(expr->args); |
| 182 | +secondExpr=lsecond(expr->args); |
| 183 | +if (nodeTag(firstExpr)!=T_Expr||nodeTag(secondExpr)!=T_Expr) |
| 184 | +return0; |
| 185 | + |
| 186 | +if (firstExpr->opType==AND_EXPR) |
| 187 | +fr=inspectAndNode(firstExpr); |
| 188 | +elseif (firstExpr->opType==OP_EXPR) |
| 189 | +fr=inspectOpNode(firstExpr); |
| 190 | + |
| 191 | +if (secondExpr->opType==OP_EXPR) |
| 192 | +sr=inspectOpNode(secondExpr); |
| 193 | + |
| 194 | +return (fr&&sr); |
| 195 | +} |
| 196 | + |
| 197 | + |
| 198 | +staticint |
| 199 | +/****************************************************************** |
| 200 | + * Return TRUE if T_Var = T_Const, else FALSE |
| 201 | + * Actually it does not test for =. Need to do this! |
| 202 | + ******************************************************************/ |
| 203 | +inspectOpNode(Expr*expr) |
| 204 | +{ |
| 205 | +Expr*firstExpr,*secondExpr; |
| 206 | + |
| 207 | +if (nodeTag(expr)!=T_Expr||expr->opType!=OP_EXPR) |
| 208 | +return0; |
| 209 | + |
| 210 | +firstExpr=lfirst(expr->args); |
| 211 | +secondExpr=lsecond(expr->args); |
| 212 | +return (firstExpr&&secondExpr&&nodeTag(firstExpr)==T_Var&&nodeTag(secondExpr)==T_Const); |
| 213 | +} |