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I didn't put nolock on the update statement - I put it on the join.
You could just create a job that does the monster update at night.
".45 ACP - because shooting twice is just silly" - JSOP, 2010 ----- You can never have too much ammo - unless you're swimming, or on fire. - JSOP, 2010 ----- When you pry the gun from my cold dead hands, be careful - the barrel will be very hot. - JSOP, 2013
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Quote:
UPDATE t
...
FROM Source s
JOIN Target t WITH(NOLOCK) ON t.id = s.id
...
That NOLOCK hint is on the target table. It's exactly the same as the first example from the article I linked to:
UPDATE t1
SET t1.x = something
FROM dbo.t1 WITH (NOLOCK)
INNER JOIN ...;
"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer
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We use WITH(NOLOCK) prolifically. Of course, we have indexes on all of our tables, and don't generally do massive updates in the middle of the work day. We have no issues.
".45 ACP - because shooting twice is just silly" - JSOP, 2010 ----- You can never have too much ammo - unless you're swimming, or on fire. - JSOP, 2010 ----- When you pry the gun from my cold dead hands, be careful - the barrel will be very hot. - JSOP, 2013
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NOLOCK can cause nonclustered index corruption, and it's also deprecated[^].
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That's something for our DBAs to worry about.
".45 ACP - because shooting twice is just silly" - JSOP, 2010 ----- You can never have too much ammo - unless you're swimming, or on fire. - JSOP, 2010 ----- When you pry the gun from my cold dead hands, be careful - the barrel will be very hot. - JSOP, 2013
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Have you tried using a MERGE statement?
".45 ACP - because shooting twice is just silly" - JSOP, 2010 ----- You can never have too much ammo - unless you're swimming, or on fire. - JSOP, 2010 ----- When you pry the gun from my cold dead hands, be careful - the barrel will be very hot. - JSOP, 2013
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Yes.
The update in my OP is greatly simplified.
The actual update is a merge with more than 4000 rows.
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I'm not too familiar with MongoDB. In our MongoDb we're currently using the default Guid keys.
However, I don't see any reason not to use Init PKs.
Our base Entity has the following
public class _EntityBase : _BindableBase
{
[BsonId(IdGenerator = typeof(GuidGenerator))]
[BsonRepresentation(BsonType.String)]
[DataMember]
public Guid Id { get; set; }
}
Any reason not to change it to ints?
public class _EntityBase : _BindableBase
{
[BsonId(IdGenerator = typeof(MongoDBIntIdGenerator))]
[BsonRepresentation(BsonType.Int64)]
public int Id { get; set; }
}
If it's not broken, fix it until it is.
Everything makes sense in someone's mind.
Ya can't fix stupid.
modified 17-May-19 14:47pm.
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Because the key is generated on the client not the server.
So if you only have one client, ever, then no not much of a problem. But if you want to add another server then it starts to be a problem.
MongoDB integer primary key (nodejs example) using server side functions[^]
In general the sort of things that a int id in a SQL database which might be solved are not the same as for NoSQL (mongodb). For example the overhead for storing each document (instance) is already so high that and saving with an int is almost insignificant. And if it is a matter of retrieval speed then look to some other solution that would provide real performance rather than the small (if any) gain that this might produce.
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jschell wrote: Because the key is generated on the client not the server.
So what if I created a PK table on the sever:
public int GetNextPrimaryKey(string collectionName)
{
lock(_lockObj)
{
IMongoCollection<PrimaryKeyEntity> pkCol = GetCollection<PrimaryKeyEntity>("PrimaryKeys");
PrimaryKeyEntity entity = pkCol.Find(x => x.CollectionName == collectionName).FirstOrDefault();
if (entity == null)
{
entity = new PrimaryKeyEntity
{
PrimaryKey = 1,
CollectionName = collectionName
};
pkCol.InsertOne(entity);
}
else
{
entity.PrimaryKey = entity.PrimaryKey + 1;
var filter = Builders<PrimaryKeyEntity>.Filter.Eq(x => x.CollectionName, collectionName);
var update = Builders<PrimaryKeyEntity>.Update.Set(x => x.PrimaryKey, entity.PrimaryKey);
var result = pkCol.UpdateOneAsync(filter, update).Result;
}
return entity.PrimaryKey;
}
}
If it's not broken, fix it until it is.
Everything makes sense in someone's mind.
Ya can't fix stupid.
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Kevin Marois wrote: So what if I created a PK table on the sever:
In this scenario...
(some caller) -> (app server) -> (database server)
In the above the 'app server' is the 'client' for the 'database server'
If you create the key on the 'app server' then you have the following choices (locking in your code has no impact on this.)
1. There can only be one server.
2. You will need to create/find a mechanism the correlates the id creation between multiple 'app server' instances.
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How to add a single data for multiple times using MySQL
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At a guess, by writing some code that runs in a loop. But if you want a proper answer you will need to provide more information about what you are trying to do.
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Actually, the concept is..."if i select january 2018 and enter some data that data should enter repeatedly from january to december 2018....if i select november 2018 and enter some data that data should enter repeatedly from november to december 2018..." Based on Month we selecting it should enter into database....Here i got the answer but i want query to insert....[Can't able to insert multiple data].
Here is my Query which i have in my code....
"INSERT INTO alem_meeting (meeting_date, meeting_start_time, meeting_end_time, meeting_type, meeting_manager_name, meeting_manager_email, meeting_client_name, meeting_client_contact, meeting_client_email, meeting_client_address1, meeting_client_address2, meeting_special_notes, meeting_status)VALUES ?";
Error which is showing there:
"VALUES ?"
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You have 13 column names but you only specify a single VALUE.
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Here i'm using NodeJs for server side
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Can I just run this past you guys, to check I'm not losing my mind...
I use a hosted webserver for a number of my sites, that each use a MySql database. Most use StoredProcs to access data. Yesterday, all the SP-based ones stopped working, with a variety of error messages. No code had changed. Trying to connect to the databases using HeidiSQL or MySql Workbench threw up warnings that the tools didn't support v10.2.24... now I thought I was on MySql 5.7 or something...?
Digging deeper reveals that v10.2.24 is the current MariaDB version. Checking with my hosting provider, and asking why they'd not only upgraded version but changed from MySql to MariaDB without telling anyone, I got this reply:
Quote: MySQL 5.7 is the last version of MySQL to be called MySQL
MariaDB is the new name for what was MySQL, so thare is noting to move back to. [sic]
This is news to me!!!
I found the following (really useful) article from less than two weeks ago: MariaDB vs MySQL in 2019: Compatibility, Performance, and Syntax[^]
Please, tell me my hosting provider is talking rubbish!!
Oddly enough, after giving more detail on the issue, everything started working normally again (but still reporting potential compatibility issues with 10.2.24 when using Workbench or Heidi). I'm guessing they'd not configured MariaDB to support StoredProcs (is that even an option?) but whatever they've done seems to have done the trick. But my confidence in them is very severely shaken, when they change d/bs without informing customers, and seem to think MariaDB 10.2.24 is just the new name for MySql 5.7 (and they don't even seem to know about MySql 8.0!) ....
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DerekTP123 wrote: Please, tell me my hosting provider is talking rubbish!
Yes they are.
MariaDB is a clone taken from the MySQL code base when Oracle acquired it. So now there are two products. And more specifically two different development branches which are different. The branch wasn't a recent one either.
So upgrading from MySQL to MariaDB is a product change. And likely a disruptive one as well.
Compare this to AWS Aurora which is also a different product but one that promises binary equality.
Might also note, my impression (without any research) is that stored procedures might be impacted the most.
That said if you are not tied to MySQL for marketing reasons then my gut would say that MariaDB might, in general, be a better product. If for no other reason then Oracle absolutely will pour more money into their commercial MySQL offering than they will into the open source version.
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Thanks, JSchell. I later found that although my apps were generally working OK, a couple of functions were failing. Digging deeper I found the issue was that on one StoredProc there was a "missing" parameter, and another was just missing altogether. Everything else was fine. I deduce from this that once alerted to the issue, they probably realised they'd forgotten to migrate the SPs and did a quick manual copy/paste. It's not a huge hosting company and although they have a few hundred databases, I suspect only a handful - or fewer - are using SPs so they may not even have been aware until I pointed out the issue.
They previously (last October) migrated to a new server op.system plus MySql upgrade. That also broke most of my sites since many call webservices on other domains, and the new server didn't support some of the older security protocols the sites were using. It was a one-line fix for each but took quite a while to identify. Also I couldn't send any emails via the SMTP server; I reported it and they claimed nothing had changed, but magically it started working about 10 minutes after I raised the ticket. Seriously p***ed off with them. They've given me a year's free hosting as compensation but when they continually break sites by screwing up upgrades (with no advance warning) I'd rather pay someone to do a proper job....
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You might want to take a longer look at where you think your company/product is going.
Like I said I suspect MariaDb is better but, far as I can tell, there is more broad support for MySQL.
So if you think that you might want to move to a different host in three years then you should take care to continue to test and develop on MySQL. That would make your upgrade path easier then although harder now since you probably need to test on both. Although perhaps you could use that as a marketing claim ("runs on both!").
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Fortunately it's a bespoke application for a specific client, so we'll host it wherever they want - and the choice of d/b will be part of that decision making process. In fact the whole data access layer is pretty much "pluggable" and switching DBMS is a non-event as far as the application itself is concerned - the only impact would be on stored procedures. So I'm not too fussed which d/b the host uses - what concerns me far more is that they think they can just "upgrade" one to another, and with no advance warning, no support, no awareness that the two are not 100% compatible, and not even knowing that they're different products, rather than just a later version. It's a real shame, because 15 years ago when I first started using them, they were small but outstanding. Expert support staff who really knew their product, and would go out of their way to assist and adapt as needed. They appreciated the importance of reliable and predictable service levels and the reputational damage outages could do for their clients. That ethos seems to have been abandoned...
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DerekTP123 wrote: rather than just a later version. It's a real shame, because 15 years ago when I first started using them
I suspect that 15 years ago you also were different. So could be that they have gotten worse but could also be that you have become more discerning. Or a combination.
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