How to optimally and reliably go about sequentially applying updates with long running transactions?

On Sat, Jan 14, 2017 at 12:52 AM, Mustard Seed <supercriticalfluid at gmail.com> wrote: > I'm new to BaseX and XQuery, so I apologize if there's some glaring thing > I've missed. > > What I have are three updating functions that I'm wanting to have executed > sequentially, successfully, to BaseX. > > When I simply place them in my RestXQ function, delimited by commas, they > all execute, but since at times certain ones take longer than others, and > since their results can overwrite/negate the results of each other, I can't > manage to get them to consistently execute in the same order. > > It seems to me that since it seemingly is running in parallel that whatever > happens to end last determines what my final state is. > > I imagine there's got to be some blatantly obvious way to do this, but I'm > just not finding it, I went through the BaseX manual a second time and have > searched every possible combination of things I can think of to try and > figure out a way around this. > > > One function does a mass delete of all dbs with a given prefix, another > repopulates from a sql query, and a third updates the repopulated dbs based > on yet another sql query. That's the order I want it to execute in, I'm just > about at my wits end trying to figure out how to do this. I was even getting > into trying to pull off a hackish attempt at making jobs which I'd schedule > based on a rough guess of the longest expected execution times for the > functions. But even that wasn't working. > > Any help will be greatly appreciated as insuring the order of execution is > rather vital for the overall project I'm trying to do, so I need to not only > find a solution for the present use case, but I need to understand how to > insure such for any future composite functions. > > Thanks, > > --Nicolai

On Sat, Jan 14, 2017 at 10:40 AM, Christian Grün <christian.gruen at gmail.com> wrote: > Hi Nicolai, > > Welcome to the list. > > The semantics of XQuery Update ensures that updates will be executed > after at the end of query evaluation. This also means that your udates > will always be executed at the same order [1]. > > In many cases, it will be possibly to rewrite sequential update > operations to single ones. If that’s not possible – and in your case > it may be tricky – you will have to define them in multiple RESTXQ > functions and call them successively (see e.g. [2]). > > Feel free to provide us with a minimized example, and I can give you > some more hints. > > Cheers, > Christian > > [1] http://docs.basex.org/wiki/XQuery_Update#Concepts > [2] http://docs.basex.org/wiki/RESTXQ#Response > > > On Sat, Jan 14, 2017 at 12:52 AM, Mustard Seed > <supercriticalfluid at gmail.com> wrote: >> I'm new to BaseX and XQuery, so I apologize if there's some glaring thing >> I've missed. >> >> What I have are three updating functions that I'm wanting to have executed >> sequentially, successfully, to BaseX. >> >> When I simply place them in my RestXQ function, delimited by commas, they >> all execute, but since at times certain ones take longer than others, and >> since their results can overwrite/negate the results of each other, I can't >> manage to get them to consistently execute in the same order. >> >> It seems to me that since it seemingly is running in parallel that whatever >> happens to end last determines what my final state is. >> >> I imagine there's got to be some blatantly obvious way to do this, but I'm >> just not finding it, I went through the BaseX manual a second time and have >> searched every possible combination of things I can think of to try and >> figure out a way around this. >> >> >> One function does a mass delete of all dbs with a given prefix, another >> repopulates from a sql query, and a third updates the repopulated dbs based >> on yet another sql query. That's the order I want it to execute in, I'm just >> about at my wits end trying to figure out how to do this. I was even getting >> into trying to pull off a hackish attempt at making jobs which I'd schedule >> based on a rough guess of the longest expected execution times for the >> functions. But even that wasn't working. >> >> Any help will be greatly appreciated as insuring the order of execution is >> rather vital for the overall project I'm trying to do, so I need to not only >> find a solution for the present use case, but I need to understand how to >> insure such for any future composite functions. >> >> Thanks, >> >> --Nicolai