什么是好的C#编码风格追赶的SQLException并重试 [英] What is good C# coding style for catching SQLException and retrying
问题描述
我有一个调用一个SQLServer函数来执行对表的自由文本搜索的方法。这个函数会偶尔在第一次调用导致SQLException:断字超时为全文查询字符串。所以通常我要重试请求,因为它会在后续请求成功。什么是好的风格以构建重试逻辑。目前,我有以下几点:
VAR RetryCount重= 0;
VAR的结果=新的List< UserSummaryDto>();
使用(VAR CTX =新UsersDataContext(ConfigurationManager.ConnectionStrings [CONNECTION_STRING_KEY] .ConnectionString))
{
对于(;)
{
尝试
{
结果= ctx.SearchPhoneList(值,maxRows进行)
。选择(用户= GT; user.ToDto())
.ToList();
打破;
}
赶上(SQLEXCEPTION)
{
RetryCount重++;
如果(RetryCount重> MAX_RETRY)抛出;
}
}
}返回结果;
感谢所有的反馈。我这个回答自己,所以我可以将来自给出的答案元素。请让我知道如果我错过了一些东西。我的方法就变成了:
VAR的结果=新的List< UserSummaryDto>();
重试< UsersDataContext>(CTX =>业绩= ctx.SearchPhoneList(值,maxRows进行)
。选择(用户= GT; user.ToDto())
.ToList());
返回结果;
和我重构重用原来的方法。仍然很多嵌套层次。它也依赖于学生要这可能是过于严格的数据上下文默认构造函数。 @马丁,我考虑包括您的 preserveStackTrace 的方法,但在这种情况下,我不认为它确实增加了足够的价值 - 好知道以供将来参考感谢:
私人const int的MAX_RETRY = 2;
私人常量双LONG_WAIT_SECONDS = 5;
私人常量双SHORT_WAIT_SECONDS = 0.5;
私人静态只读时间跨度longWait = TimeSpan.FromSeconds(LONG_WAIT_SECONDS);
私人静态只读时间跨度shortWait = TimeSpan.FromSeconds(SHORT_WAIT_SECONDS);
私人枚举RetryableSqlErrors
{
超时= -2,
NOLOCK = 1204,
死锁= 1205,
WordbreakerTimeout = 30053,
}私人无效重试< T>(动作< T> retryAction)其中T:DataContext的,新的()
{
变种RetryCount重= 0;
使用(VAR CTX =新T())
{
为(;;)
{
尝试
{
retryAction(CTX);
打破;
}
赶上(SQLEXCEPTION EX)
{
如果(!Enum.IsDefined(typeof运算(RetryableSqlErrors),ex.Number))
扔; RetryCount重++;
如果(RetryCount重> MAX_RETRY)抛出; Thread.sleep代码(ex.Number ==(INT)RetryableSqlErrors.Timeout?
longWait:shortWait);
}
}
}
}
I have a method that calls a SQLServer function to perform a free text search against a table. That function will occasionally on the first call result in a SQLException: "Word breaking timed out for the full-text query string". So typically I want to retry that request because it will succeed on subsequent requests. What is good style for structuring the retry logic. At the moment I have the following:
var retryCount = 0;
var results = new List<UserSummaryDto>();
using (var ctx = new UsersDataContext(ConfigurationManager.ConnectionStrings[CONNECTION_STRING_KEY].ConnectionString))
{
for (; ; )
{
try
{
results = ctx.SearchPhoneList(value, maxRows)
.Select(user => user.ToDto())
.ToList();
break;
}
catch (SqlException)
{
retryCount++;
if (retryCount > MAX_RETRY) throw;
}
}
}
return results;
Thanks for all the feedback. I'm answering this myself so I can incorporate elements from the answers given. Please let me know if I've missed something. My method becomes:
var results = new List<UserSummaryDto>();
Retry<UsersDataContext>(ctx => results = ctx.SearchPhoneList(value, maxRows)
.Select(user => user.ToDto())
.ToList());
return results;
And I've refactored the original method for reuse. Still lots of levels of nesting. It also relies on there being a default constructor for the data context which may be too restrictive. @Martin, I considered including your PreserveStackTrace method but in this case I don't think it really adds enough value - good to know for future reference thanks:
private const int MAX_RETRY = 2;
private const double LONG_WAIT_SECONDS = 5;
private const double SHORT_WAIT_SECONDS = 0.5;
private static readonly TimeSpan longWait = TimeSpan.FromSeconds(LONG_WAIT_SECONDS);
private static readonly TimeSpan shortWait = TimeSpan.FromSeconds(SHORT_WAIT_SECONDS);
private enum RetryableSqlErrors
{
Timeout = -2,
NoLock = 1204,
Deadlock = 1205,
WordbreakerTimeout = 30053,
}
private void Retry<T>(Action<T> retryAction) where T : DataContext, new()
{
var retryCount = 0;
using (var ctx = new T())
{
for (;;)
{
try
{
retryAction(ctx);
break;
}
catch (SqlException ex)
{
if (!Enum.IsDefined(typeof( RetryableSqlErrors), ex.Number))
throw;
retryCount++;
if (retryCount > MAX_RETRY) throw;
Thread.Sleep(ex.Number == (int) RetryableSqlErrors.Timeout ?
longWait : shortWait);
}
}
}
}
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