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优化内存分配

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陈梓阳
2024-01-16 15:35:54 +08:00
committed by lindj
parent dadb36b1c9
commit 1de3603afe
5 changed files with 89 additions and 113 deletions
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144
ConsoleApp2/Services/MySqlDestination.cs
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@@ -1,5 +1,4 @@
using System.Reflection.Metadata;
using System.Text;
using System.Text;
using ConsoleApp2.Helpers;
using ConsoleApp2.Options;
using Microsoft.Extensions.Logging;
@@ -17,22 +16,18 @@ public class MySqlDestination : IDisposable, IAsyncDisposable
private readonly Dictionary<string, IList<DataRecord>> _recordCache;
private readonly MySqlConnection _conn;
private readonly ILogger _logger;
private readonly bool _prettyOutput;
private readonly int _maxAllowPacket;
private readonly ProcessContext _context;
public MySqlDestination(string connStr, ILogger logger, ProcessContext context,bool prettyOutput = false)
private readonly IOptions<DataTransformOptions> _transformOptions;
public MySqlDestination(string connStr, ILogger logger, ProcessContext context, IOptions<DataTransformOptions> transformOptions)
{
_conn = new MySqlConnection(connStr);
_conn.Open();
_recordCache = new Dictionary<string, IList<DataRecord>>();
_logger = logger;
_context = context;
_prettyOutput = prettyOutput;
_transformOptions = transformOptions;
}
public Task WriteRecordAsync(DataRecord record)
{
_recordCache.AddOrUpdate(record.TableName, [record], (key, value) =>
@@ -51,20 +46,22 @@ public class MySqlDestination : IDisposable, IAsyncDisposable
}
}
public async Task FlushAsync(int maxAllowPacket, IOptions<DataTransformOptions> transOptions)
public async Task FlushAsync(int maxAllowPacket)
{
if (_recordCache.Count == 0)
return;
var cmd = _conn.CreateCommand();
cmd.CommandTimeout = 3 * 60;
var excuseList = GetExcuseList(_recordCache, maxAllowPacket, transOptions, _prettyOutput);
try
{
var excuseList = GetExcuseList(_recordCache, maxAllowPacket).ToList();
foreach (var insertSql in excuseList)
{
cmd.CommandText = insertSql;
await cmd.ExecuteNonQueryAsync();
_logger.LogInformation(@"do insert completed!size:{Length}", cmd.CommandText.Length);
}
_recordCache.Clear();
}
@@ -80,89 +77,94 @@ public class MySqlDestination : IDisposable, IAsyncDisposable
}
}
public static IList<string> GetExcuseList(IDictionary<string, IList<DataRecord>> tableRecords,int maxAllowPacket, IOptions<DataTransformOptions> transOptions,
bool prettyOutput = false)
public IEnumerable<string> GetExcuseList(IDictionary<string, IList<DataRecord>> tableRecords,int maxAllowPacket)
{
var resultList = new List<string>();
var headerSb = new StringBuilder();
var recordSb = new StringBuilder();
var sb = new StringBuilder();
foreach (var (tableName, records) in tableRecords)
{
if (records.Count == 0)
continue;
headerSb.Append($"INSERT INTO `{tableName}`(");
var recordIdx = 0;
StartBuild:
var noCommas = true;
// INSERT INTO ... VALUES >>>
sb.Append($"INSERT INTO `{tableName}`(");
for (var i = 0; i < records[0].Headers.Length; i++)
{
var header = records[0].Headers[i];
headerSb.Append($"`{header}`");
sb.Append($"`{header}`");
if (i != records[0].Headers.Length - 1)
headerSb.Append(',');
sb.Append(',');
}
headerSb.Append(") VALUES ");
if (prettyOutput)
headerSb.AppendLine();
var sbList = new List<string>();
var currentLength = headerSb.Length;
for (var i = 0; i < records.Count; i++)
sb.Append(") VALUES ");
// ([FIELDS]), >>>
for (;recordIdx < records.Count; recordIdx++)
{
var record = records[i];
var record = records[recordIdx];
var recordSb = new StringBuilder();
recordSb.Append('(');
for (var j = 0; j < record.Fields.Length; j++)
for (var fieldIdx = 0; fieldIdx < record.Fields.Length; fieldIdx++)
{
var field = record.Fields[j];
var header = record.Headers[j];
if (transOptions.Value.GetColumnType(record.TableName, header) ==ColumnType.Blob)
var field = record.Fields[fieldIdx];
// 在这里处理特殊列
#region HandleFields
if (field == "\\N")
{
if (string.IsNullOrEmpty(field))
{
recordSb.Append("NULL");
}
else
recordSb.Append("0x"+field);
recordSb.Append("NULL");
goto Escape;
}
else
recordSb.Append(field);
if (j != record.Fields.Length - 1)
switch (_transformOptions.Value.GetColumnType(record.TableName, record.Headers[fieldIdx]))
{
case ColumnType.Text:
recordSb.Append(string.IsNullOrEmpty(field)
? "''"
: _transformOptions.Value.TransformBinary?.Invoke(field) ?? field);
break;
case ColumnType.Blob:
if (string.IsNullOrEmpty(field))
recordSb.Append("NULL");
else recordSb.Append($"0x{field}");
break;
case ColumnType.UnDefine:
default:
recordSb.Append(field);
break;
}
Escape:
#endregion
if (fieldIdx != record.Fields.Length - 1)
recordSb.Append(',');
}
recordSb.Append(')');
//if (i != records.Count - 1) // not last field
// recordSb.Append(',');
if (prettyOutput) recordSb.AppendLine();
// 若字符数量即将大于限制，则返回SQL，清空StringBuilder，保留当前记录的索引值，然后转到StartBuild标签重新开始一轮INSERT
if (sb.Length + recordSb.Length + 1 > maxAllowPacket)
{
sb.Append(';');
yield return sb.ToString();
sb.Clear();
goto StartBuild;
}
if (currentLength + recordSb.Length >= maxAllowPacket)
{
var insertSb = new StringBuilder(headerSb.ToString());
insertSb.Append(string.Join(",", sbList));
insertSb.Append(";");
resultList.Add(insertSb.ToString());
insertSb.Clear();
sbList.Clear();
sbList.Add(recordSb.ToString());
currentLength = headerSb.Length + 1;//逗号长度加1
}
else
{
sbList.Add(recordSb.ToString());
}
currentLength += recordSb.Length;
recordSb.Clear();
if (!noCommas)
sb.Append(',').AppendLine();
noCommas = false;
sb.Append(recordSb); // StringBuilder.Append(StringBuilder)不会分配多余的内存
}
if (sbList.Count > 0)
{
var insertSb = new StringBuilder(headerSb.ToString());
insertSb.Append(string.Join(",", sbList));
insertSb.Append(";");
resultList.Add(insertSb.ToString());
insertSb.Clear();
}
headerSb.Clear();
sb.Append(';');
yield return sb.ToString();
sb.Clear();
}
return resultList;
}