/
formula.go
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/
formula.go
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/*---------------------------------------------------------------------------------------------
* Copyright (c) IBAX. All rights reserved.
* See LICENSE in the project root for license information.
*--------------------------------------------------------------------------------------------*/
package querycost
import (
"errors"
"strings"
"github.com/IBAX-io/go-ibax/packages/consts"
"github.com/IBAX-io/go-ibax/packages/storage/sqldb"
log "github.com/sirupsen/logrus"
)
const (
Select = "select"
Insert = "insert"
Update = "update"
Delete = "delete"
Set = "set"
From = "from"
Into = "into"
Quote = `"`
Lparen = "("
)
const (
SelectCost = 1
UpdateCost = 1
InsertCost = 1
DeleteCost = 1
SelectRowCoeff = 0.0001
InsertRowCoeff = 0.0001
DeleteRowCoeff = 0.0001
UpdateRowCoeff = 0.0001
)
var FromStatementMissingError = errors.New("FROM statement missing")
var DeleteMinimumThreeFieldsError = errors.New("DELETE query must consist minimum of 3 fields")
var SetStatementMissingError = errors.New("SET statement missing")
var IntoStatementMissingError = errors.New("INTO statement missing")
var UnknownQueryTypeError = errors.New("Unknown query type")
func strSliceIndex(fields []string, fieldToFind string) (index int) {
for i, field := range fields {
if field == fieldToFind {
index = i
break
}
}
return
}
type TableRowCounter interface {
RowCount(*sqldb.DbTransaction, string) (int64, error)
}
type DBCountQueryRowCounter struct {
}
func (d *DBCountQueryRowCounter) RowCount(transaction *sqldb.DbTransaction, tableName string) (int64, error) {
count, err := transaction.GetRecordsCountTx(tableName, ``)
if err != nil {
log.WithFields(log.Fields{"type": consts.DBError, "error": err, "table": tableName}).Error("Getting record count from table")
}
return count, err
}
type FormulaQueryCoster struct {
rowCounter TableRowCounter
}
type QueryType interface {
GetTableName() (string, error)
CalculateCost(int64) int64
}
type SelectQueryType string
func (s SelectQueryType) GetTableName() (string, error) {
queryFields := strings.Fields(string(s))
fromFieldIndex := strSliceIndex(queryFields, From)
if fromFieldIndex == 0 {
return "", nil
}
return strings.Trim(queryFields[fromFieldIndex+1], Quote), nil
}
func (s SelectQueryType) CalculateCost(rowCount int64) int64 {
return SelectCost + int64(SelectRowCoeff*float64(rowCount))
}
type UpdateQueryType string
func (s UpdateQueryType) GetTableName() (string, error) {
queryFields := strings.Fields(string(s))
setFieldIndex := strSliceIndex(queryFields, Set)
if setFieldIndex == 0 {
return "", SetStatementMissingError
}
return strings.Trim(queryFields[setFieldIndex-1], Quote), nil
}
func (s UpdateQueryType) CalculateCost(rowCount int64) int64 {
return UpdateCost + int64(UpdateRowCoeff*float64(rowCount))
}
type InsertQueryType string
func (s InsertQueryType) GetTableName() (string, error) {
queryFields := strings.Fields(string(s))
intoFieldIndex := strSliceIndex(queryFields, Into)
if intoFieldIndex == 0 {
return "", IntoStatementMissingError
}
tableNameValuesField := queryFields[intoFieldIndex+1]
tableName := ""
lparenIndex := strings.Index(tableNameValuesField, Lparen)
if lparenIndex > 0 {
tableName = tableNameValuesField[:lparenIndex]
} else {
tableName = tableNameValuesField
}
return strings.Trim(tableName, Quote), nil
}
func (s InsertQueryType) CalculateCost(rowCount int64) int64 {
return InsertCost
}
type DeleteQueryType string
func (s DeleteQueryType) GetTableName() (string, error) {
queryFields := strings.Fields(string(s))
fromFieldIndex := strSliceIndex(queryFields, From)
if fromFieldIndex == 0 {
return "", FromStatementMissingError
}
// DELETE FROM table is minimum
if len(queryFields) < 3 {
return "", DeleteMinimumThreeFieldsError
}
return strings.Trim(queryFields[fromFieldIndex+1], Quote), nil
}
func (s DeleteQueryType) CalculateCost(rowCount int64) int64 {
return DeleteCost + int64(DeleteRowCoeff*float64(rowCount))
}
func (f *FormulaQueryCoster) QueryCost(transaction *sqldb.DbTransaction, query string, args ...any) (int64, error) {
cleanedQuery := strings.TrimSpace(strings.ToLower(query))
var queryType QueryType
switch {
case strings.HasPrefix(cleanedQuery, Select):
queryType = SelectQueryType(cleanedQuery)
case strings.HasPrefix(cleanedQuery, Insert):
queryType = InsertQueryType(cleanedQuery)
case strings.HasPrefix(cleanedQuery, Update):
queryType = UpdateQueryType(cleanedQuery)
case strings.HasPrefix(cleanedQuery, Delete):
queryType = DeleteQueryType(cleanedQuery)
default:
log.WithFields(log.Fields{"type": consts.ParseError, "query": query}).Error("parsing sql query")
return 0, UnknownQueryTypeError
}
tableName, err := queryType.GetTableName()
if err != nil {
log.WithFields(log.Fields{"type": consts.ParseError, "query": query, "error": err}).Error("getting table name from sql query")
return 0, err
}
rowCount, err := f.rowCounter.RowCount(transaction, tableName)
if err != nil {
return 0, err
}
return queryType.CalculateCost(rowCount), nil
}