Examples with LetClause org.apache.asterix.lang.common.clause.LetClause used on opensource projects

Example 1 with LetClause

use of org.apache.asterix.lang.common.clause.LetClause in project asterixdb by apache.

the class SqlppGroupByVisitor method visit.

@Override
public Expression visit(SelectBlock selectBlock, ILangExpression arg) throws CompilationException {
    // Traverses the select block in the order of "from", "let"s, "where",
    // "group by", "let"s, "having" and "select".
    FromClause fromClause = selectBlock.getFromClause();
    if (selectBlock.hasFromClause()) {
        fromClause.accept(this, arg);
    }
    if (selectBlock.hasLetClauses()) {
        List<LetClause> letList = selectBlock.getLetList();
        for (LetClause letClause : letList) {
            letClause.accept(this, arg);
        }
    }
    if (selectBlock.hasWhereClause()) {
        selectBlock.getWhereClause().accept(this, arg);
    }
    if (selectBlock.hasGroupbyClause()) {
        GroupbyClause groupbyClause = selectBlock.getGroupbyClause();
        groupbyClause.accept(this, fromClause);
        Collection<VariableExpr> visibleVarsInCurrentScope = SqlppVariableUtil.getBindingVariables(groupbyClause);
        VariableExpr groupVar = groupbyClause.getGroupVar();
        Set<VariableExpr> groupFieldVars = getGroupFieldVariables(groupbyClause);
        Collection<VariableExpr> freeVariablesInGbyLets = new HashSet<>();
        if (selectBlock.hasLetClausesAfterGroupby()) {
            List<LetClause> letListAfterGby = selectBlock.getLetListAfterGroupby();
            for (LetClause letClauseAfterGby : letListAfterGby) {
                letClauseAfterGby.accept(this, arg);
                // Rewrites each let clause after the group-by.
                SqlppRewriteUtil.rewriteExpressionUsingGroupVariable(groupVar, groupFieldVars, letClauseAfterGby, context);
                Collection<VariableExpr> freeVariablesInLet = SqlppVariableUtil.getFreeVariables(letClauseAfterGby.getBindingExpr());
                freeVariablesInLet.removeAll(visibleVarsInCurrentScope);
                freeVariablesInGbyLets.addAll(freeVariablesInLet);
                visibleVarsInCurrentScope.add(letClauseAfterGby.getVarExpr());
            }
        }
        Collection<VariableExpr> freeVariables = new HashSet<>();
        if (selectBlock.hasHavingClause()) {
            // Rewrites the having clause.
            HavingClause havingClause = selectBlock.getHavingClause();
            havingClause.accept(this, arg);
            SqlppRewriteUtil.rewriteExpressionUsingGroupVariable(groupVar, groupFieldVars, havingClause, context);
            freeVariables.addAll(SqlppVariableUtil.getFreeVariables(havingClause));
        }
        SelectExpression parentSelectExpression = (SelectExpression) arg;
        // We cannot rewrite ORDER BY and LIMIT if it's a SET operation query.
        if (!parentSelectExpression.getSelectSetOperation().hasRightInputs()) {
            if (parentSelectExpression.hasOrderby()) {
                // Rewrites the ORDER BY clause.
                OrderbyClause orderbyClause = parentSelectExpression.getOrderbyClause();
                orderbyClause.accept(this, arg);
                SqlppRewriteUtil.rewriteExpressionUsingGroupVariable(groupVar, groupFieldVars, orderbyClause, context);
                freeVariables.addAll(SqlppVariableUtil.getFreeVariables(orderbyClause));
            }
            if (parentSelectExpression.hasLimit()) {
                // Rewrites the LIMIT clause.
                LimitClause limitClause = parentSelectExpression.getLimitClause();
                limitClause.accept(this, arg);
                SqlppRewriteUtil.rewriteExpressionUsingGroupVariable(groupVar, groupFieldVars, limitClause, context);
                freeVariables.addAll(SqlppVariableUtil.getFreeVariables(limitClause));
            }
        }
        // Visits the select clause.
        SelectClause selectClause = selectBlock.getSelectClause();
        selectClause.accept(this, arg);
        // Rewrites the select clause.
        SqlppRewriteUtil.rewriteExpressionUsingGroupVariable(groupVar, groupFieldVars, selectClause, context);
        freeVariables.addAll(SqlppVariableUtil.getFreeVariables(selectClause));
        freeVariables.removeAll(visibleVarsInCurrentScope);
        // Gets the final free variables.
        freeVariables.addAll(freeVariablesInGbyLets);
        // Gets outer scope variables.
        Collection<VariableExpr> decorVars = SqlppVariableUtil.getLiveVariables(scopeChecker.getCurrentScope(), true);
        decorVars.removeAll(visibleVarsInCurrentScope);
        // Need path resolution or not?
        boolean needResolution = !decorVars.containsAll(freeVariables);
        // Otherwise, we only need to retain used free variables.
        if (needResolution) {
            // Tracks used variables, including WITH variables.
            decorVars.retainAll(freeVariables);
            // Adds all non-WITH outer scope variables, for path resolution.
            Collection<VariableExpr> visibleOuterScopeNonWithVars = SqlppVariableUtil.getLiveVariables(scopeChecker.getCurrentScope(), false);
            visibleOuterScopeNonWithVars.removeAll(visibleVarsInCurrentScope);
            decorVars.addAll(visibleOuterScopeNonWithVars);
        } else {
            // Only retains used free variables.
            decorVars.retainAll(freeVariables);
        }
        if (!decorVars.isEmpty()) {
            // Adds used WITH variables.
            Collection<VariableExpr> visibleOuterScopeNonWithVars = SqlppVariableUtil.getLiveVariables(scopeChecker.getCurrentScope(), false);
            visibleOuterScopeNonWithVars.retainAll(freeVariables);
            decorVars.addAll(visibleOuterScopeNonWithVars);
            // Adds necessary decoration variables for the GROUP BY.
            // NOTE: we need to include WITH binding variables so as they can be evaluated before
            // the GROUP BY instead of being inlined as part of nested pipepline. The current optimzier
            // is not able to optimize the latter case. The following query is such an example:
            // asterixdb/asterix-app/src/test/resources/runtimets/queries_sqlpp/dapd/q2-11
            List<GbyVariableExpressionPair> decorList = new ArrayList<>();
            for (VariableExpr var : decorVars) {
                decorList.add(new GbyVariableExpressionPair((VariableExpr) SqlppRewriteUtil.deepCopy(var), (Expression) SqlppRewriteUtil.deepCopy(var)));
            }
            groupbyClause.getDecorPairList().addAll(decorList);
        }
    } else {
        selectBlock.getSelectClause().accept(this, arg);
    }
    return null;
}

Example 2 with LetClause

use of org.apache.asterix.lang.common.clause.LetClause in project asterixdb by apache.

the class SqlppInlineUdfsVisitor method visit.

@Override
public Boolean visit(SelectBlock selectBlock, List<FunctionDecl> funcs) throws CompilationException {
    boolean changed = false;
    if (selectBlock.hasFromClause()) {
        changed |= selectBlock.getFromClause().accept(this, funcs);
    }
    if (selectBlock.hasLetClauses()) {
        for (LetClause letClause : selectBlock.getLetList()) {
            changed |= letClause.accept(this, funcs);
        }
    }
    if (selectBlock.hasWhereClause()) {
        changed |= selectBlock.getWhereClause().accept(this, funcs);
    }
    if (selectBlock.hasGroupbyClause()) {
        changed |= selectBlock.getGroupbyClause().accept(this, funcs);
    }
    if (selectBlock.hasLetClausesAfterGroupby()) {
        for (LetClause letClause : selectBlock.getLetListAfterGroupby()) {
            changed |= letClause.accept(this, funcs);
        }
    }
    if (selectBlock.hasHavingClause()) {
        changed |= selectBlock.getHavingClause().accept(this, funcs);
    }
    changed |= selectBlock.getSelectClause().accept(this, funcs);
    return changed;
}

Example 3 with LetClause

use of org.apache.asterix.lang.common.clause.LetClause in project asterixdb by apache.

the class SqlppInlineUdfsVisitor method extractLetBindingVariableExpressionMappings.

private Map<Expression, Expression> extractLetBindingVariableExpressionMappings(List<LetClause> letClauses) throws CompilationException {
    Map<Expression, Expression> varExprMap = new HashMap<>();
    for (LetClause lc : letClauses) {
        // inline let variables one by one iteratively.
        lc.setBindingExpr(SqlppRewriteUtil.substituteExpression(lc.getBindingExpr(), varExprMap, context));
        varExprMap.put(lc.getVarExpr(), lc.getBindingExpr());
    }
    return varExprMap;
}

Example 4 with LetClause

use of org.apache.asterix.lang.common.clause.LetClause in project asterixdb by apache.

the class SubstituteGroupbyExpressionVisitor method visit.

@Override
public Expression visit(SelectBlock selectBlock, ILangExpression arg) throws CompilationException {
    if (selectBlock.hasGroupbyClause()) {
        Map<Expression, Expression> map = new HashMap<>();
        for (GbyVariableExpressionPair gbyKeyPair : selectBlock.getGroupbyClause().getGbyPairList()) {
            Expression gbyKeyExpr = gbyKeyPair.getExpr();
            if (gbyKeyExpr.getKind() != Kind.VARIABLE_EXPRESSION) {
                map.put(gbyKeyExpr, gbyKeyPair.getVar());
            }
        }
        // Creates a substitution visitor.
        SubstituteGroupbyExpressionVisitor visitor = new SubstituteGroupbyExpressionVisitor(context, map);
        // Rewrites LET/HAVING/SELECT clauses.
        if (selectBlock.hasLetClausesAfterGroupby()) {
            for (LetClause letClause : selectBlock.getLetListAfterGroupby()) {
                letClause.accept(this, arg);
            }
        }
        if (selectBlock.hasHavingClause()) {
            selectBlock.getHavingClause().accept(visitor, arg);
        }
        selectBlock.getSelectClause().accept(visitor, arg);
        SelectExpression selectExpression = (SelectExpression) arg;
        // For SET operation queries, the GROUP BY key variables will not substitute ORDER BY nor LIMIT expressions.
        if (!selectExpression.getSelectSetOperation().hasRightInputs()) {
            if (selectExpression.hasOrderby()) {
                selectExpression.getOrderbyClause().accept(visitor, arg);
            }
            if (selectExpression.hasLimit()) {
                selectExpression.getLimitClause().accept(visitor, arg);
            }
        }
    }
    return super.visit(selectBlock, arg);
}

Example 5 with LetClause

use of org.apache.asterix.lang.common.clause.LetClause in project asterixdb by apache.

the class AbstractInlineUdfsVisitor method inlineUdfsInExpr.

protected Pair<Boolean, Expression> inlineUdfsInExpr(Expression expr, List<FunctionDecl> arg) throws CompilationException {
    if (expr.getKind() != Kind.CALL_EXPRESSION) {
        boolean r = expr.accept(this, arg);
        return new Pair<>(r, expr);
    }
    CallExpr f = (CallExpr) expr;
    boolean r = expr.accept(this, arg);
    FunctionDecl implem = findFuncDeclaration(f.getFunctionSignature(), arg);
    if (implem == null) {
        return new Pair<>(r, expr);
    } else {
        // Rewrite the function body itself (without setting unbounded variables to dataset access).
        // TODO(buyingyi): throw an exception for recursive function definition or limit the stack depth.
        implem.setFuncBody(rewriteFunctionBody(implem.getFuncBody()));
        // it's one of the functions we want to inline
        List<LetClause> clauses = new ArrayList<>();
        Iterator<VarIdentifier> paramIter = implem.getParamList().iterator();
        VariableSubstitutionEnvironment subts = new VariableSubstitutionEnvironment();
        for (Expression e : f.getExprList()) {
            VarIdentifier param = paramIter.next();
            // variable inlining to take care of this.
            if (e.getKind() == Kind.VARIABLE_EXPRESSION) {
                subts.addSubstituion(new VariableExpr(param), e);
            } else {
                VarIdentifier newV = context.newVariable();
                Pair<ILangExpression, VariableSubstitutionEnvironment> p1 = e.accept(cloneVisitor, new VariableSubstitutionEnvironment());
                LetClause c = new LetClause(new VariableExpr(newV), (Expression) p1.first);
                clauses.add(c);
                subts.addSubstituion(new VariableExpr(param), new VariableExpr(newV));
            }
        }
        Pair<ILangExpression, VariableSubstitutionEnvironment> p2 = implem.getFuncBody().accept(cloneVisitor, subts);
        Expression resExpr;
        if (clauses.isEmpty()) {
            resExpr = (Expression) p2.first;
        } else {
            resExpr = generateQueryExpression(clauses, (Expression) p2.first);
        }
        return new Pair<>(true, resExpr);
    }
}