f162d7bd97
Avoid unnecessary pointer reference allocations
when not needed, for example
- *SelectFuncs{}
- *Row{}
443 lines
14 KiB
Go
443 lines
14 KiB
Go
/*
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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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"encoding/json"
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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/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, myRow chan Row) {
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reqCols, alias, myLimit, whereClause, aggFunctionNames, myFuncs, myErr := ParseSelect(f)
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if myErr != nil {
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myRow <- Row{
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err: myErr,
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}
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return
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}
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processSelectReq(reqCols, alias, whereClause, myLimit, aggFunctionNames, myRow, myFuncs, 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, interface{}, []string, SelectFuncs, error) {
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var sFuncs = SelectFuncs{}
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var whereClause interface{}
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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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functionNames := 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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switch expr := stmt.Where.Expr.(type) {
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default:
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whereClause = expr
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case *sqlparser.ComparisonExpr:
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whereClause = expr
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}
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}
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if stmt.SelectExprs != nil {
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for i := 0; i < len(stmt.SelectExprs); i++ {
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switch expr := stmt.SelectExprs[i].(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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functionNames[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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}
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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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if (stmt.From) != nil {
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for i := 0; i < len(stmt.From); i++ {
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switch smallerexpr := stmt.From[i].(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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}
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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, functionNames, 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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// 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, whereClause interface{}, limitOfRecords int64, functionNames []string, myRow chan Row, myFunc SelectFuncs, f format.Select) {
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counter := -1
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var columns []string
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filtrCount := 0
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functionFlag := false
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// My values is used to store our aggregation values if we need to store them.
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myAggVals := make([]float64, len(reqColNames))
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// LowercasecolumnsMap is used in accordance with hasDuplicates so that we can
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// raise the error "Ambigious" if a case insensitive column is provided and we
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// have multiple matches.
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lowercaseColumnsMap := make(map[string]int)
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hasDuplicates := make(map[string]bool)
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// ColumnsMap stores our columns and their index.
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columnsMap := make(map[string]int)
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if limitOfRecords == 0 {
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limitOfRecords = math.MaxInt64
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}
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for {
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record, err := f.Read()
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if err != nil {
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myRow <- 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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myRow <- Row{
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record: aggFuncToStr(myAggVals, f) + "\n",
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}
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}
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close(myRow)
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return
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}
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out, _ := json.Marshal(record)
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f.UpdateBytesProcessed(record)
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if counter == -1 && f.HasHeader() && len(f.Header()) > 0 {
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columns = f.Header()
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myErr := checkForDuplicates(columns, columnsMap, hasDuplicates, lowercaseColumnsMap)
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if format.IsInt(reqColNames[0]) {
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myErr = ErrMissingHeaders
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}
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if myErr != nil {
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myRow <- Row{
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err: myErr,
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}
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return
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}
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} else if counter == -1 && len(f.Header()) > 0 {
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columns = f.Header()
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for i := 0; i < len(columns); i++ {
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columnsMap["_"+strconv.Itoa(i)] = i
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}
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}
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// Return in case the number of record reaches the LIMIT defined in select query
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if int64(filtrCount) == limitOfRecords && limitOfRecords != 0 {
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close(myRow)
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return
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}
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// The call to the where function clause,ensures that the rows we print match our where clause.
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condition, myErr := matchesMyWhereClause(record, alias, whereClause)
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if myErr != nil {
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myRow <- Row{
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err: myErr,
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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] == "*" && functionNames[0] == "" {
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var row Row
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switch f.Type() {
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case format.CSV:
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row = Row{
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record: strings.Join(convertToSlice(columnsMap, record, string(out)), f.OutputFieldDelimiter()) + "\n",
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}
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case format.JSON:
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row = Row{
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record: string(out) + "\n",
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}
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}
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myRow <- row
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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(functionNames) > 0 && functionNames[0] != "" {
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functionFlag = true
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aggregationFunctions(counter, filtrCount, myAggVals, reqColNames, functionNames, string(out))
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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 and utilizes the map to
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// retrieve the correct part of the row.
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myQueryRow, myErr := processColNameIndex(string(out), reqColNames, columns, f)
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if myErr != nil {
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myRow <- Row{
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err: myErr,
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}
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return
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}
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myRow <- Row{
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record: myQueryRow + "\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 acutal names rather an indices.
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if len(functionNames) > 0 && functionNames[0] != "" {
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functionFlag = true
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aggregationFunctions(counter, filtrCount, myAggVals, reqColNames, functionNames, string(out))
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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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myQueryRow, myErr := processColNameLiteral(string(out), reqColNames, myFunc, f)
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if myErr != nil {
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myRow <- Row{
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err: myErr,
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}
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return
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}
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myRow <- Row{
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record: myQueryRow + "\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 := 0; i < len(reqColNames); i++ {
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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
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// query.
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func processColNameIndex(record string, reqColNames []string, columns []string, f format.Select) (string, error) {
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row := make([]string, len(reqColNames))
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for i := 0; i < len(reqColNames); i++ {
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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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mytempindex, err := strconv.Atoi(reqColNames[i])
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if mytempindex > len(columns) {
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return "", format.ErrInvalidColumnIndex
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}
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if err != nil {
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return "", ErrMissingHeaders
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}
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// Subtract 1 because AWS Indexing is not 0 based, it starts at 1 generating the key like "_1".
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row[i] = jsonValue(string("_"+strconv.Itoa(mytempindex-1)), record)
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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
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// query.
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func processColNameLiteral(record string, reqColNames []string, myFunc SelectFuncs, f format.Select) (string, error) {
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row := make([]string, len(reqColNames))
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for i := 0; i < len(reqColNames); i++ {
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// this is the case to deal with COALESCE.
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if reqColNames[i] == "" && isValidFunc(myFunc.index, i) {
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row[i] = evaluateFuncExpr(myFunc.funcExpr[i], "", record)
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continue
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}
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row[i] = jsonValue(reqColNames[i], record)
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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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// aggregationFunctions 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 aggregationFunctions(counter int, filtrCount int, myAggVals []float64, storeReqCols []string, storeFunctions []string, record string) error {
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for i := 0; i < len(storeFunctions); i++ {
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if storeFunctions[i] == "" {
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i++
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} else if storeFunctions[i] == "count" {
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myAggVals[i]++
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} else {
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// If column names are provided as an index it'll use this if statement instead of the else/
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var convAggFloat float64
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if format.IsInt(storeReqCols[i]) {
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myIndex, _ := strconv.Atoi(storeReqCols[i])
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convAggFloat, _ = strconv.ParseFloat(jsonValue(string("_"+strconv.Itoa(myIndex)), record), 64)
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} else {
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// case that the columns are in the form of named columns rather than indices.
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convAggFloat, _ = strconv.ParseFloat(jsonValue(storeReqCols[i], record), 64)
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}
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// This if statement is for calculating the min.
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if storeFunctions[i] == "min" {
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if counter == -1 {
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myAggVals[i] = math.MaxFloat64
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}
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if convAggFloat < myAggVals[i] {
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myAggVals[i] = convAggFloat
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}
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} else if storeFunctions[i] == "max" {
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// This if statement is for calculating the max.
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if counter == -1 {
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myAggVals[i] = math.SmallestNonzeroFloat64
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}
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if convAggFloat > myAggVals[i] {
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myAggVals[i] = convAggFloat
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}
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} else if storeFunctions[i] == "sum" {
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// This if statement is for calculating the sum.
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myAggVals[i] += convAggFloat
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} else if storeFunctions[i] == "avg" {
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// This if statement is for calculating the average.
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if filtrCount == 0 {
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myAggVals[i] = convAggFloat
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} else {
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myAggVals[i] = (convAggFloat + (myAggVals[i] * float64(filtrCount))) / float64((filtrCount + 1))
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}
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} else {
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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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// convertToSlice takes the map[string]interface{} and convert it to []string
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func convertToSlice(columnsMap map[string]int, record map[string]interface{}, marshalledRecord string) []string {
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var result []string
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type kv struct {
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Key string
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Value int
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}
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var ss []kv
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for k, v := range columnsMap {
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ss = append(ss, kv{k, v})
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}
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sort.Slice(ss, func(i, j int) bool {
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return ss[i].Value < ss[j].Value
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})
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for _, kv := range ss {
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if _, ok := record[kv.Key]; ok {
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result = append(result, jsonValue(kv.Key, marshalledRecord))
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}
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}
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return result
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}
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