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434 lines
12 KiB
434 lines
12 KiB
/*
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* Minio Cloud Storage, (C) 2018 Minio, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package s3select
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import (
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"math"
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"sort"
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"strconv"
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"strings"
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"github.com/minio/minio/pkg/s3select/format"
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"github.com/tidwall/gjson"
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"github.com/xwb1989/sqlparser"
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)
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// SelectFuncs contains the relevant values from the parser for S3 Select
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// Functions
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type SelectFuncs struct {
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funcExpr []*sqlparser.FuncExpr
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index []int
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}
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// RunSqlParser allows us to easily bundle all the functions from above and run
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// them in the appropriate order.
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func runSelectParser(f format.Select, rowCh chan Row) {
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reqCols, alias, limit, wc, aggFunctionNames, fns, err := ParseSelect(f)
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if err != nil {
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rowCh <- Row{
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err: err,
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}
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return
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}
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processSelectReq(reqCols, alias, wc, limit, aggFunctionNames, rowCh, fns, f)
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}
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// ParseSelect parses the SELECT expression, and effectively tokenizes it into
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// its separate parts. It returns the requested column names,alias,limit of
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// records, and the where clause.
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func ParseSelect(f format.Select) ([]string, string, int64, sqlparser.Expr, []string, SelectFuncs, error) {
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var sFuncs = SelectFuncs{}
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var whereClause sqlparser.Expr
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var alias string
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var limit int64
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stmt, err := sqlparser.Parse(f.Expression())
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// TODO: Maybe can parse their errors a bit to return some more of the s3 errors
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if err != nil {
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return nil, "", 0, nil, nil, sFuncs, ErrLexerInvalidChar
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}
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switch stmt := stmt.(type) {
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case *sqlparser.Select:
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// evaluates the where clause
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fnNames := make([]string, len(stmt.SelectExprs))
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columnNames := make([]string, len(stmt.SelectExprs))
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if stmt.Where != nil {
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whereClause = stmt.Where.Expr
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}
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for i, sexpr := range stmt.SelectExprs {
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switch expr := sexpr.(type) {
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case *sqlparser.StarExpr:
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columnNames[0] = "*"
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case *sqlparser.AliasedExpr:
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switch smallerexpr := expr.Expr.(type) {
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case *sqlparser.FuncExpr:
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if smallerexpr.IsAggregate() {
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fnNames[i] = smallerexpr.Name.CompliantName()
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// Will return function name
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// Case to deal with if we have functions and not an asterix
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switch tempagg := smallerexpr.Exprs[0].(type) {
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case *sqlparser.StarExpr:
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columnNames[0] = "*"
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if smallerexpr.Name.CompliantName() != "count" {
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return nil, "", 0, nil, nil, sFuncs, ErrParseUnsupportedCallWithStar
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}
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case *sqlparser.AliasedExpr:
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switch col := tempagg.Expr.(type) {
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case *sqlparser.BinaryExpr:
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return nil, "", 0, nil, nil, sFuncs, ErrParseNonUnaryAgregateFunctionCall
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case *sqlparser.ColName:
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columnNames[i] = col.Name.CompliantName()
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}
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}
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// Case to deal with if COALESCE was used..
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} else if supportedFunc(smallerexpr.Name.CompliantName()) {
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if sFuncs.funcExpr == nil {
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sFuncs.funcExpr = make([]*sqlparser.FuncExpr, len(stmt.SelectExprs))
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sFuncs.index = make([]int, len(stmt.SelectExprs))
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}
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sFuncs.funcExpr[i] = smallerexpr
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sFuncs.index[i] = i
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} else {
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return nil, "", 0, nil, nil, sFuncs, ErrUnsupportedSQLOperation
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}
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case *sqlparser.ColName:
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columnNames[i] = smallerexpr.Name.CompliantName()
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}
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}
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}
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// This code retrieves the alias and makes sure it is set to the correct
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// value, if not it sets it to the tablename
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for _, fexpr := range stmt.From {
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switch smallerexpr := fexpr.(type) {
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case *sqlparser.JoinTableExpr:
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return nil, "", 0, nil, nil, sFuncs, ErrParseMalformedJoin
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case *sqlparser.AliasedTableExpr:
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alias = smallerexpr.As.CompliantName()
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if alias == "" {
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alias = sqlparser.GetTableName(smallerexpr.Expr).CompliantName()
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}
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}
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}
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if stmt.Limit != nil {
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switch expr := stmt.Limit.Rowcount.(type) {
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case *sqlparser.SQLVal:
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// The Value of how many rows we're going to limit by
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parsedLimit, _ := strconv.Atoi(string(expr.Val[:]))
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limit = int64(parsedLimit)
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}
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}
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if stmt.GroupBy != nil {
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return nil, "", 0, nil, nil, sFuncs, ErrParseUnsupportedLiteralsGroupBy
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}
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if stmt.OrderBy != nil {
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return nil, "", 0, nil, nil, sFuncs, ErrParseUnsupportedToken
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}
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if err := parseErrs(columnNames, whereClause, alias, sFuncs, f); err != nil {
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return nil, "", 0, nil, nil, sFuncs, err
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}
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return columnNames, alias, limit, whereClause, fnNames, sFuncs, nil
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}
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return nil, "", 0, nil, nil, sFuncs, nil
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}
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type columnKv struct {
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Key string
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Value int
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}
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func columnsIndex(reqColNames []string, f format.Select) ([]columnKv, error) {
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var (
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columnsKv []columnKv
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columnsMap = make(map[string]int)
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columns = f.Header()
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)
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if f.HasHeader() {
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err := checkForDuplicates(columns, columnsMap)
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if format.IsInt(reqColNames[0]) {
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err = ErrMissingHeaders
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}
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if err != nil {
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return nil, err
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}
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for k, v := range columnsMap {
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columnsKv = append(columnsKv, columnKv{
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Key: k,
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Value: v,
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})
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}
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} else {
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for i := range columns {
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columnsKv = append(columnsKv, columnKv{
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Key: "_" + strconv.Itoa(i),
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Value: i,
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})
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}
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}
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sort.Slice(columnsKv, func(i, j int) bool {
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return columnsKv[i].Value < columnsKv[j].Value
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})
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return columnsKv, nil
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}
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// This is the main function, It goes row by row and for records which validate
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// the where clause it currently prints the appropriate row given the requested
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// columns.
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func processSelectReq(reqColNames []string, alias string, wc sqlparser.Expr, lrecords int64, fnNames []string, rowCh chan Row, fn SelectFuncs, f format.Select) {
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counter := -1
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filtrCount := 0
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functionFlag := false
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// Values used to store our aggregation values.
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aggVals := make([]float64, len(reqColNames))
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if lrecords == 0 {
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lrecords = math.MaxInt64
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}
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columnsKv, err := columnsIndex(reqColNames, f)
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if err != nil {
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rowCh <- Row{
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err: err,
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}
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return
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}
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var results = make([]string, len(columnsKv))
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for {
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record, err := f.Read()
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if err != nil {
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rowCh <- Row{
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err: err,
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}
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return
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}
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if record == nil {
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if functionFlag {
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rowCh <- Row{
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record: aggFuncToStr(aggVals, f) + "\n",
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}
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}
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close(rowCh)
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return
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}
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f.UpdateBytesProcessed(int64(len(record)))
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// Return in case the number of record reaches the LIMIT
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// defined in select query
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if int64(filtrCount) == lrecords {
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close(rowCh)
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return
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}
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// The call to the where function clause, ensures that
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// the rows we print match our where clause.
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condition, err := matchesMyWhereClause(record, alias, wc)
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if err != nil {
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rowCh <- Row{
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err: err,
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}
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return
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}
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if condition {
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// if its an asterix we just print everything in the row
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if reqColNames[0] == "*" && fnNames[0] == "" {
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switch f.Type() {
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case format.CSV:
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for i, kv := range columnsKv {
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results[i] = gjson.GetBytes(record, kv.Key).String()
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}
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rowCh <- Row{
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record: strings.Join(results, f.OutputFieldDelimiter()) + "\n",
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}
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case format.JSON:
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rowCh <- Row{
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record: string(record) + "\n",
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}
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}
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} else if alias != "" {
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// This is for dealing with the case of if we have to deal with a
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// request for a column with an index e.g A_1.
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if format.IsInt(reqColNames[0]) {
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// This checks whether any aggregation function was called as now we
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// no longer will go through printing each row, and only print at the end
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if len(fnNames) > 0 && fnNames[0] != "" {
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functionFlag = true
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aggregationFns(counter, filtrCount, aggVals, reqColNames, fnNames, record)
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} else {
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// The code below finds the appropriate columns of the row given the
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// indicies provided in the SQL request.
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var rowStr string
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rowStr, err = processColNameIndex(record, reqColNames, f)
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if err != nil {
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rowCh <- Row{
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err: err,
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}
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return
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}
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rowCh <- Row{
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record: rowStr + "\n",
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}
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}
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} else {
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// This code does aggregation if we were provided column names in the
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// form of actual names rather an indices.
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if len(fnNames) > 0 && fnNames[0] != "" {
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functionFlag = true
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aggregationFns(counter, filtrCount, aggVals, reqColNames, fnNames, record)
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} else {
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// This code prints the appropriate part of the row given the filter
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// and select request, if the select request was based on column
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// names rather than indices.
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var rowStr string
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rowStr, err = processColNameLiteral(record, reqColNames, fn, f)
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if err != nil {
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rowCh <- Row{
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err: err,
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}
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return
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}
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rowCh <- Row{
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record: rowStr + "\n",
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}
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}
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}
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}
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filtrCount++
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}
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counter++
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}
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}
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// processColumnNames is a function which allows for cleaning of column names.
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func processColumnNames(reqColNames []string, alias string, f format.Select) error {
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switch f.Type() {
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case format.CSV:
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for i := range reqColNames {
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// The code below basically cleans the column name of its alias and other
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// syntax, so that we can extract its pure name.
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reqColNames[i] = cleanCol(reqColNames[i], alias)
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}
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case format.JSON:
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// JSON doesnt have columns so no cleaning required
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}
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return nil
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}
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// processColNameIndex is the function which creates the row for an index based query.
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func processColNameIndex(record []byte, reqColNames []string, f format.Select) (string, error) {
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var row []string
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for _, colName := range reqColNames {
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// COALESCE AND NULLIF do not support index based access.
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if reqColNames[0] == "0" {
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return "", format.ErrInvalidColumnIndex
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}
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cindex, err := strconv.Atoi(colName)
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if err != nil {
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return "", ErrMissingHeaders
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}
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if cindex > len(f.Header()) {
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return "", format.ErrInvalidColumnIndex
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}
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// Subtract 1 because SELECT indexing is not 0 based, it
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// starts at 1 generating the key like "_1".
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row = append(row, gjson.GetBytes(record, string("_"+strconv.Itoa(cindex-1))).String())
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}
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rowStr := strings.Join(row, f.OutputFieldDelimiter())
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if len(rowStr) > MaxCharsPerRecord {
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return "", ErrOverMaxRecordSize
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}
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return rowStr, nil
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}
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// processColNameLiteral is the function which creates the row for an name based query.
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func processColNameLiteral(record []byte, reqColNames []string, fn SelectFuncs, f format.Select) (string, error) {
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row := make([]string, len(reqColNames))
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for i, colName := range reqColNames {
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// this is the case to deal with COALESCE.
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if colName == "" && isValidFunc(fn.index, i) {
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row[i] = evaluateFuncExpr(fn.funcExpr[i], "", record)
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continue
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}
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row[i] = gjson.GetBytes(record, colName).String()
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}
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rowStr := strings.Join(row, f.OutputFieldDelimiter())
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if len(rowStr) > MaxCharsPerRecord {
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return "", ErrOverMaxRecordSize
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}
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return rowStr, nil
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}
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// aggregationFns is a function which performs the actual aggregation
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// methods on the given row, it uses an array defined in the main parsing
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// function to keep track of values.
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func aggregationFns(counter int, filtrCount int, aggVals []float64, storeReqCols []string, storeFns []string, record []byte) error {
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for i, storeFn := range storeFns {
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switch storeFn {
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case "":
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continue
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case "count":
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aggVals[i]++
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default:
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// Column names are provided as an index it'll use
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// this if statement instead.
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var convAggFloat float64
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if format.IsInt(storeReqCols[i]) {
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index, _ := strconv.Atoi(storeReqCols[i])
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convAggFloat = gjson.GetBytes(record, "_"+strconv.Itoa(index)).Float()
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} else {
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// Named columns rather than indices.
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convAggFloat = gjson.GetBytes(record, storeReqCols[i]).Float()
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}
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switch storeFn {
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case "min":
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if counter == -1 {
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aggVals[i] = math.MaxFloat64
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}
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if convAggFloat < aggVals[i] {
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aggVals[i] = convAggFloat
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}
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case "max":
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// Calculate the max.
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if counter == -1 {
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aggVals[i] = math.SmallestNonzeroFloat64
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}
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if convAggFloat > aggVals[i] {
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aggVals[i] = convAggFloat
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}
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case "sum":
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// Calculate the sum.
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aggVals[i] += convAggFloat
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case "avg":
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// Calculating the average.
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if filtrCount == 0 {
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aggVals[i] = convAggFloat
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} else {
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aggVals[i] = (convAggFloat + (aggVals[i] * float64(filtrCount))) / float64((filtrCount + 1))
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}
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default:
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return ErrParseNonUnaryAgregateFunctionCall
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}
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}
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}
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return nil
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}
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