all.
I has written a program connectting Azure sql DB using JPA, within the code, I set the query timeout as below:
Map<String,Object> map = new HashMap<String, Object>();
map.put("javax.persistence.lock.timeout", 0);
return this.getEntityManager().find( cls, id, LockModeType.PESSIMISTIC_WRITE,map);
I hope it will return null immediately in case the query can not get the lock under the row.
but it didnot work, it always blocked there.
Is it something wrong? or did sqlserver driver not support timeout?
thanks a lot.
It probably is not supported, but if you include the SQL that was generated, this could be confirmed.
You could also try setting the query timeout,
"eclipselink.jdbc.timeout"="100"
Or, if you are using EclipseLink, you could use,
"eclipselink.pessimistic-lock"="LockNoWait"
Related
Using servicestack ormlite 6,4 and azure SQL server - using SQLServerDialect2012, we have an issue with an enums causing excessive stalling and timeouts.
If we just convert it to a string its quick as it should be.
var results = db.Select(q => q.SomeColumn == enum.value); -> 3,5 seconds
var results2 = db.Select(q => q.SomeColumn.tostring() == enum.value.tostring()); -> 0,08
we are using default settings so the enum in the db is defined as a varchar(255)
both queries give the same result.
to track the issue we wanted to see what its actually firing, but all we get is a query with some #1 #2 etc with no indication of what parameters where used or how they are defined.
All our attempts to get a 1:1 SQL string we can use to manually test the query and see the results have failed... mini profiler was the closest as it shows the parameter values...
but it does not contain the details necessary to recreate the used query and recreate the issue we have. (manually recreating the query gives 80ms as above)
Trying to get the execution plan with the query also fail.
db.ExecuteSql("SET STATISTICS PROFILE ON;");
var results = db.Select(q => q.SomeColumn == enum.value);
db.ExecuteSql("SET STATISTICS PROFILE OFF;");
only returns data, not any extra info i was hoping for.
I have not been able to find any sites or threads that explain how others get any kind of debug info.
What is the correct next step here?
OrmLite's Logging & Introspection page shows how you can view the SQL generated by OrmLite.
E.g. Configuring a debug logger should log the generated SQL and params:
LogManager.LogFactory = new ConsoleLogFactory(debugEnabled:true);
When I have a query generated like this:
var query = from x in Entities.SomeTable
select x;
I can set a breakpoint and after hovering cursor over query I can see what will be the SQL command sent to database. Unfortunately I cannot do it when I use Count
var query = (from x in Entities.SomeTable
select x).Count();
Of course I could see what comes to SqlServer using profiler but maybe someone has any idea how to do it (if it is possible) in VS.
You can use ToTraceString():
ObjectQuery<SomeTable> query = (from x in Entities.SomeTable select x).Count();
Console.WriteLine(query.ToTraceString());
You can use the Database.Log to log any query made like this :
using (var context = new MyContext())
{
context.Database.Log = Console.Write;
// Your code here...
}
Usually, in my context's constructor, I set that to my logger (whether it is NLog, Log4Net, or the stock .net loggers) and not the console, but actual logging tool is irrelevant.
For more information
In EF6 and above, you can use the following before your query:
context.Database.Log = s => System.Diagnostics.Debug.WriteLine(s);
I've found this to be quicker than pulling up SQL Profiler and running a trace.
Also, this post talks more about this topic:
How do I view the SQL generated by the Entity Framework?
I am using MS SQL server 2008 with Hibernate. the question I have is how Hibernate implements setMaxResults
Take the following simple scenario.
If I have a query that returns 100 rows and if I pass 1 to setMaxResults, will this affect the returned result from the SQL server itself(as if running a select top 1 statement) or does Hibernate get all the results first (all 100 rows in this case) and pick the top one itself?
Reason I am asking is that it would have a huge performance issue when the number of rows starts to grow.
Thank you.
Hibernate will generate a limit-type query, for all dialects which supports limit query. As the SQLServerDialect supports this (see org.hibernate.dialect.SQLServerDialect.supportsLimit(), and .getLimitString()), you will get a select top 1-query.
If you would like to be absolutly sure, you may turn on debug-logging, or enable the showSql-option and test.
May be following snippet will help. Assume we have a managed Bean class EmpBean and we want only first 5 records. So following is the code
public List<EmpBean> getData()
{
Session session = null;
try
{
session = HibernateUtil.getSession();
Query qry = session.createQuery("FROM EmpBean");
qry.setMaxResults(5);
return qry.list();
}
catch(HibernateException e)
{}
finally
{
HibernateUtil.closeSession(session);
}
return null;
}
Here getSession and closeSession are static utility methods which will take care of creating and closing session
I was wondering if someone knows where I can see the data of a suspended message in the biztalk database.
I need this because about 900 messages have been suspended because of a validation and I need to edit all of them, resuming isn't possible.
I know that info of suspended messages are shown in BizTalkMsgBoxDb in the table InstancesSuspended and that the different parts of each message are shown in the table MessageParts. However I can't find the table where the actual data is stored.
Does anyone have any idea where this can be done?
I found a way to do this, there's no screwing up my system when I just want to read them.
How I did it is using the method "CompressionStreams" using Microsoft.Biztalk.Pipeline.dll.
The method to do this:
public static Stream getMsgStrm(Stream stream)
{
Assembly pipelineAssembly = Assembly.LoadFrom(string.Concat(#"<path to dll>", #"\Microsoft.BizTalk.Pipeline.dll"));
Type compressionStreamsType = pipelineAssembly.GetType("Microsoft.BizTalk.Message.Interop.CompressionStreams", true);
return (Stream)compressionStreamsType.InvokeMember("Decompress", BindingFlags.Public | BindingFlags.InvokeMethod | BindingFlags.Static, null, null, new object[] { (object)stream });
}
Then I connect with my database, fill in a dataset and stream out the data to string, code:
String SelectCmdString = "select * from dbo.Parts";
SqlDataAdapter mySqlDataAdapter = new SqlDataAdapter(SelectCmdString, "<your connectionstring">);
DataSet myDataSet = new DataSet();
mySqlDataAdapter.Fill(myDataSet, "BodyParts");
foreach (DataRow row in myDataSet.Tables["BodyParts"].Rows)
{
if (row["imgPart"].GetType() != typeof(DBNull))
{
SqlBinary binData = new SqlBinary((byte[])row["imgPart"]);
MemoryStream stm = new MemoryStream(binData.Value);
Stream aStream = getMsgStrm(stm);
StreamReader aReader = new StreamReader(aStream);
string aMessage = aReader.ReadToEnd();
//filter msg
//write msg
}
}
I then write each string to an appropriate "txt" or "xml" depending on what u want, you can also filter out certain messages with regular expression, etc.
Hope this helps anyone, it sure as hell helped me.
Greetings
Extract Messages from suspended instances
Scenario:
BizTalk 2010 and SQL 2008 R2 is the environment we have used fore this scenario.
You have problem with some integrations, 1500 suspended instances inside BizTalk and you need to send the actual messages to a customer, and then you properly do not want to manually save out this from BizTalk Administrator.
There are a lot of blogs and Internet resources pointing out vbs, powershell scripts how to do this, but I have used BizTalk Terminator to solve this kind of scenarios.
As you now BizTalk terminator is asking you 3 questions when the tool starts
I.1.All BizTalk databases are backed up?
II.2.All Host Instances is stopped?
III.3.All BizTalk SQL Agents is stopped?
This is ok when you are going to actually change something inside BizTalk databases but this is not what you are going to do in this scenario you are only using the tool to read from BizTalk databases. But you should always have backups off BizTalk databases.
You are always responsible for what you are doing, but when we have used this tools in the way I describe we have not have any problem with this scenario.
So after you have start Terminator tool please click yes to the 3 questions(you dont need to stop anything in this scenario) then connect to the correct environment please do this in your test environment first so you feel comfortable with this scenario, the next step is to choose a terminator task choose Count Instances(and save messages) after this you have to fill in the parameter TAB with correct serviceClass and Hostname and set SaveMessages to True and last set FilesaveFullPath to the correct folder you want to save the messages to.
Then you can choose to click on the Execute Button and depending of the size and how many it can take some time, after this disconnect Terminator do NOT do anything else.
You should now if you have filled in the correct values in the parameter TAB have the saved messages inside the FilesaveFullPath folder.
Download BizTalk terminator from this address:
http://www.microsoft.com/en-us/download/details.aspx?id=2846
This is more than likely not supported by Microsoft. Don't risk screwing up your system. If you have a need to have a edit and resubmit, it needs to be built into the orchestration. Otherwise, your best bet is to use WMI to write a script to:
pull out all of the suspended messages
terminate them
edit them
resubmit them
you can find it through the HAT tool you just need to specify the schema ,port and the exact date
with the exact time and it will show you the messages right click on the desired one and save .
We have a couple of mirrored SQL Server databases.
My first problem - the key problem - is to get a notification when the db fails over. I don't need to know because, erm, its mirrored and so it (almost) all carries on working automagically but it would useful to be advised and I'm currently getting failovers when I don't think I should be so it want to know when they occur (without too much digging) to see if I can determine why.
I have services running that I could fairly easily use to monitor this - so the alternative question would be "How do I programmatically determine which is the principal and which is the mirror" - preferably in a more intelligent fashion than just attempting to connect each in turn (which would mostly work but...).
Thanks, Murph
Addendum:
One of the answers queries why I don't need to know when it fails over - the answer is that we're developing using ADO.NET and that has automatic failover support, all you have to do is add Failover Partner=MIRRORSERVER (where MIRRORSERVER is the name of your mirror server instance) to your connection string and your code will fail over transparently - you may get some errors depending on what connections are active but in our case very few.
Right,
The two answers and a little thought got me to something approaching an answer.
First a little more clarification:
The app is written in C# (2.0+) and uses ADO.NET to talk to SQL Server 2005.
The mirror setup is two W2k3 servers hosting the Principal and the Mirror plus a third server hosting an express instance as a monitor. The nice thing about this is a failover is all but transparent to the app using the database, it will throw an error for some connections but fundamentally everything will carry on nicely. Yes we're getting the odd false positive but the whole point is to have the system carry on working with the least amount of fuss and mirror does deliver this very nicely.
Further, the issue is not with serious server failure - that's usually a bit more obvious but with a failover for other reasons (c.f. the false positives above) as we do have a couple of things that can't, for various reasons, fail over and in any case so we can see if we can identify the circumstance where we get false positives.
So, given the above, simply checking the status of the boxes is not quite enough and chasing through the event log is probably overly complex - the answer is, as it turns out, fairly simple: sp_helpserver
The first column returned by sp_helpserver is the server name. If you run the request at regular intervals saving the previous server name and doing a comparison each time you'll be able to identify when a change has taken place and then take the appropriate action.
The following is a console app that demonstrates the principal - although it needs some work (e.g. the connection ought to be non-pooled and new each time) but its enough for now (so I'd then accept this as "the" answer"). Parameters are Principal, Mirror, Database
using System;
using System.Data.SqlClient;
namespace FailoverMonitorConcept
{
class Program
{
static void Main(string[] args)
{
string server = args[0];
string failover = args[1];
string database = args[2];
string connStr = string.Format("Integrated Security=SSPI;Persist Security Info=True;Data Source={0};Failover Partner={1};Packet Size=4096;Initial Catalog={2}", server, failover, database);
string sql = "EXEC sp_helpserver";
SqlConnection dc = new SqlConnection(connStr);
SqlCommand cmd = new SqlCommand(sql, dc);
Console.WriteLine("Connection string: " + connStr);
Console.WriteLine("Press any key to test, press q to quit");
string priorServerName = "";
char key = ' ';
while(key.ToString().ToLower() != "q")
{
dc.Open();
try
{
string serverName = cmd.ExecuteScalar() as string;
Console.WriteLine(DateTime.Now.ToLongTimeString() + " - Server name: " + serverName);
if (priorServerName == "")
{
priorServerName = serverName;
}
else if (priorServerName != serverName)
{
Console.WriteLine("***** SERVER CHANGED *****");
Console.WriteLine("New server: " + serverName);
priorServerName = serverName;
}
}
catch (System.Data.SqlClient.SqlException ex)
{
Console.WriteLine("Error: " + ex.ToString());
}
finally
{
dc.Close();
}
key = Console.ReadKey(true).KeyChar;
}
Console.WriteLine("Finis!");
}
}
}
I wouldn't have arrived here without a) asking the question and then b) getting the responses which made me actually think
Murph
If the failover logic is in your application you could write a status screen that shows which box you're connected by writing to a var when the first connection attempt fails.
I think your best bet would be a ping daemon/cron job that checks the status of each box periodically and sends an email if one doesn't respond.
Use something like Host Monitor http://www.ks-soft.net/hostmon.eng/ to monitor the Event Log for messages related to the failover event, which can send you an alert via email/SMS.
I'm curious though how you wouldn't need to know that the failover happened, because don't you have to then update the datasources in your applications to point to the new server that you failed over to? Mirroring takes place on different hosts (the primary and the mirror), unlike clustering which has multiple nodes that appear to be a single device from the outside.
Also, are you using a witness server in order to automatically fail over from the primary to the mirror? This is the only way I know of to make it happen automatically, and in my experience, you get a lot of false-positives where network hiccups can fool the mirror and witness into thinking the primary is down when in fact it is not.