[英]SQL (Firebird) query too slow
到目前為止,我的程序沒有任何苛刻的功能,但后來我的功能需要花費很多時間。 它是一年中第五個月的開始,每天我的數據庫都填充了400多個文檔(每個文檔平均有5-7個項目(表到ROBA
5-7個新行)。所以經過一段時間填充,計算一切都需要花費越來越多的時間,我需要加快速度。
現在,完成所有事情需要大約60秒。 所以我想知道是否有任何方法可以加快速度,使用什么,尋找什么。 這是我的功能:
private void ucitajStanje()
{
DataTable dt1 = new DataTable();
try
{
List<List_Int_Decimal> List_roba = new List<List_Int_Decimal>();
using (FbConnection con = new FbConnection(connectionString_PrirucniMagacin))
{
con.Open();
using (FbCommand cmd = new FbCommand("SELECT ROBAID, KOLICINA FROM STAVKA WHERE VRDOK = 0 AND BRDOK = 1", con))
{
FbDataReader dr = cmd.ExecuteReader();
while (dr.Read())
{
if (!(dr[0] is DBNull))
{
List_roba.Add(new List_Int_Decimal { ROBAID = Convert.ToInt16(dr[0]), kolicina = Convert.ToDecimal(dr[1]) });
}
}
}
con.Close();
}
using (FbConnection con = new FbConnection(connectionString_Baza))
{
con.Open();
//Selektuje stanje u magacinu iz komercijalnog
using (FbDataAdapter da = new FbDataAdapter("SELECT ROBA.ROBAID, ROBA.KATBR, ROBA.NAZIV, ROBAUMAGACINU.STANJE AS STANJE_KOMERCIJALNO FROM ROBAUMAGACINU INNER JOIN ROBA ON ROBAUMAGACINU.ROBAID = ROBA.ROBAID WHERE MAGACINID = 12 AND VRSTA = 1", con))
{
da.Fill(dt1);
}
//FIRST SLOW QUERY
//izracunava stanje kartice robe bez pocetnog stanja iz komercijalnog gde se dodaje na stanje
using (FbCommand cmd = new FbCommand("SELECT ROBAID, SUM(KOLICINA) FROM STAVKA WHERE VRDOK = 16 AND ROBAID = @Robaid AND MAGACINID = 12 OR VRDOK = 18 AND ROBAID = @Robaid AND MAGACINID = 12 OR VRDOK = 22 AND ROBAID = @Robaid AND MAGACINID = 12 GROUP BY ROBAID", con))
{
cmd.Parameters.Add("@Robaid", FbDbType.Integer);
foreach (var robaid in List_roba)
{
cmd.Parameters["@Robaid"].Value = robaid.ROBAID;
FbDataReader dr = cmd.ExecuteReader();
while (dr.Read())
{
if (!(dr[0] is DBNull))
{
int trenutnaRobaId = Convert.ToInt16(dr[0]);
var roba = List_roba.Where(r => r.ROBAID == trenutnaRobaId).FirstOrDefault();
if (roba != null)
{ roba.kolicina = roba.kolicina + Convert.ToDecimal(dr[1]); }
}
}
dr.Close();
}
}
//SECOND SLOW QUERY
//izracunava stanje kartice robe bez pocetnog stanja iz komercijalnog gde se oduzima sa stanja
using (FbCommand cmd = new FbCommand("SELECT ROBAID, SUM(KOLICINA) FROM STAVKA WHERE VRDOK = 15 AND ROBAID = @Robaid AND MAGACINID = 12 OR VRDOK = 17 AND ROBAID = @Robaid AND MAGACINID = 12 OR VRDOK = 19 AND ROBAID = @Robaid AND MAGACINID = 12 OR VRDOK = 34 AND ROBAID = @Robaid AND MAGACINID = 12 GROUP BY ROBAID", con))
{
cmd.Parameters.Add("@Robaid", FbDbType.Integer);
foreach (var robaid in List_roba)
{
cmd.Parameters["@Robaid"].Value = robaid.ROBAID;
FbDataReader dr = cmd.ExecuteReader();
while (dr.Read())
{
if (!(dr[0] is DBNull))
{
int trenutnaRobaId = Convert.ToInt16(dr[0]);
var roba = List_roba.Where(r => r.ROBAID == trenutnaRobaId).FirstOrDefault();
if (roba != null)
{ roba.kolicina = roba.kolicina - Convert.ToDecimal(dr[1]); }
}
}
dr.Close();
}
}
con.Close();
}
DataTable dt2 = StaticFunctions.ToDataTable(List_roba);
var dt = new[] { dt1, dt2 };
DataTable mergedDT = StaticFunctions.MergeAll(dt, "ROBAID");
dataGridView1.DataSource = mergedDT;
dataGridView1.Columns["ROBAID"].Visible = false;
dataGridView1.Columns["KATBR"].AutoSizeMode = DataGridViewAutoSizeColumnMode.AllCells;
dataGridView1.Columns["NAZIV"].AutoSizeMode = DataGridViewAutoSizeColumnMode.Fill;
dataGridView1.Columns["STANJE_KOMERCIJALNO"].Visible = false;
dataGridView1.Columns["robaid"].Visible = false;
}
catch(Exception ex)
{
MessageBox.Show(ex.ToString());
}
}
盡量避免在循環中調用查詢(即一次又一次地執行sql):
//FIRST SLOW QUERY
// Loop!
foreach (var robaid in List_roba) {
...
// Antipattern: Many a time query calling
FbDataReader dr = cmd.ExecuteReader();
...
}
相反,執行查詢只有一次 , 一氣呵成 :
//FIRST SLOW QUERY (Hope, much faster now)
//DONE: Keep SQL readable
string sql =
@"SELECT ROBAID,
SUM(KOLICINA)
FROM STAVKA
WHERE MAGACINID = 12 AND
VRDOK IN (16, 18, 22)
GROUP BY ROBAID";
using (FbCommand cmd = new FbCommand(sql, con)) {
using (FbDataReader dr = cmd.ExecuteReader()) {
while (dr.Read()) {
if (dr.IsDBNull(0)) // <- Is it really possible for Id to be null?
continue;
int trenutnaRobaId = Convert.ToInt32(dr[0]);
//TODO: you may want to turn List_roba into Dictionary_roba:
// if (Dictionary_roba.TryGeValue(trenutnaRobaId, out roba))
// roba.kolicina = roba.kolicina + Convert.ToDecimal(dr[1]);
var roba = List_roba
.Where(r => r.ROBAID == trenutnaRobaId)
.FirstOrDefault();
if (roba != null)
roba.kolicina = roba.kolicina + Convert.ToDecimal(dr[1]);
}
}
}
編輯:如果您將List_roba
轉換為字典 (或至少創建一個臨時字典),您可以進一步提高性能,例如
// In general case, if ROBAID can have duplicates
var Dictionary_roba = List_roba
.GroupBy(item => item.ROBAID)
.ToDictionary(chunk => chunk.Key,
chunk => chunk.First());
// If ROBAID is unique:
//var Dictionary_roba = List_roba
// .ToDictionary(item => item.ROBAID, item => item);
...
using (FbCommand cmd = new FbCommand(sql, con)) {
using (FbDataReader dr = cmd.ExecuteReader()) {
while (dr.Read()) {
if (dr.IsDBNull(0)) // <- Is it really possible for Id to be null?
continue;
int trenutnaRobaId = Convert.ToInt32(dr[0]);
// C# 7.0 Syntax - out var;
// if you don't have C# 7.0 you have to declare "roba" variable
if (Dictionary_roba.TryGeValue(trenutnaRobaId, out var roba))
roba.kolicina = roba.kolicina + Convert.ToDecimal(dr[1]);
}
}
}
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