Zeoslib Portal

Hi all, I did my research and I know that this is not a bug in Zeos, but it Delphi's way of handling datasets but it's quite annoying and easy to fix. You are scrolling through a dataset, deleting some records on the way: While Not ZQuery.Eof Do If somecondition then ZQuery.Delete Else ZQuery.Next; ...

The original link is available again, but I suppose it has a better place published. Thank @mdaems (and whoever sent it to him) for the document though

Kind of a long shot, but worth a try. When I had "performance issues" (a specific data processing task took 500 ms which I found unacceptable :) ) my solution was to put the whole thing in a single transaction: Try sqlconnection.StartTransaction; TheveryLongProcedureWithLotsOfUpdates; sqlc...

Well, I was already trying to find the solution for a day when I decided to ask the community. Had a feeling that this is not a trivial issue so if I'd like to get a solution I must go into details. The rest is just the typical case of the rubber duck debugging, managed to pinpoint the weak link as ...

In this forum post there used to be a link to a PDF document called zExpression.pdf. It's a really nice one describing what you can do with the .Filter property. Unfortunately the link is not valid anymore (says 404 for me) but I managed to grab it for myself before it disappeared so I'll just reupl...

And my assumption was more than correct. It's a pain in the back to download the latest version of libmysql.dll from Oracle: - Download the web installer, then select Other, select Connectors / C, 64 bit (it can not install both at the same time... :lol:) - Next-Next-Finish, and then go to C:\Progr...

So I made some logging with Process Monitor when the delay occurs and found some really interesting things: dcdelay.PNG At 20:39:52 the worker thread (with Thread ID 10920, confirmed by checking on Delphi's side during the test) terminates. In theory the connection is already closed and the componen...

Test application: program Project1; {$APPTYPE CONSOLE} uses System.SysUtils, ZConnection, Classes; Type TWorkerThread = Class(TThread) strict private _sqlconnection: TZConnection; public Constructor Create; Reintroduce; Destructor Destroy; Override; Procedure Execute; Override; End; Var wt: TWorkerT...

Hello, I am experiencing a very strange issue. I have a formless (console) Delphi application with several worker threads. Each worker thread is creating a TZConnection in the constructor and calls the .Connect in the onExecute cycle if it is not connected. Destruction it is closing all tables, disc...

NEVER MIND.

My 64-bit MySQL installation contained a 32-bit libmysql.dll. Try to get your head around that...

I hunted a 64-bit version from the internetz and my 64-bit apps started to work immediately.

Good day, I recently tried to build one of my applications to a 64 bit Windows platform target (using Delphi 10.2). The build succeeds, but I can not connect to the MySQL server because of different reasons. I put the 32-bit libmysqld.dll in C:\Windows\SysWOW64 and the 64-bit one in C:\Windows. Both...

Yep, as far as I can see both Fr0st's and Stinkard's practices are the same. Considering the importance I guess we could say this is an other golden rule. - 1 thread = 1 database connection - Think on explicit table usage for threads if possible. If not, use a locking mechanism (in DB or in app leve...

@ Fr0sT, thank you for the clarification; that's how I imagined would be safe. @ Stinkard; that's the best setup I can think of considering thread safety and processing speed. If you keep your data in chunks (object, arrays) one thread can pick one, do it's job and load the results in the database. ...

Moreover this dummy select consumes more resources (starts/uses a transaction, creates resultset etc) than probably other driver-specific pinging methods. F.ex., FB pings by requesting DB info which doesn't require transaction and creating a resultset. This. I wish I'd have this knowledge about all...

I got a similar idea yesterday and started working on mapping specific tables explicitly to specific threads. We'll see if I can change the business logic to allow this at the end. Just keep in mind that even simultaneous access to two different tables is not safe if they belong to the same connecti...