On Fri, Nov 17, 2017 at 8:45 AM, Neel Patel <neel.pa...@enterprisedb.com> wrote:
> Hi Dave, > > On Thu, Nov 16, 2017 at 8:13 PM, Dave Page <dp...@pgadmin.org> wrote: > >> Hi >> >> On Thu, Nov 16, 2017 at 1:47 PM, Neel Patel <neel.pa...@enterprisedb.com> >> wrote: >> >>> Hi, >>> >>> Adding information. >>> >>> With this patch, RM#2715 should also be resolved. >>> >>> Thanks, >>> Neel Patel >>> >>> On Thu, Nov 16, 2017 at 7:01 PM, Neel Patel <neel.pa...@enterprisedb.com >>> > wrote: >>> >>>> Hi, >>>> >>>> I am able to reproduce the crash while downloading and save data in CSV >>>> file from query tool. >>>> >>>> Please find attached updated patch with below changes after reading Qt >>>> documentation. >>>> >>>> - Added new signal "readyRead". As per the Qt documentation, this >>>> signal will be emitted when data is ready from IO channel for large >>>> amount >>>> of data transfer between server and client. >>>> - Ready read and DownloadInProgress signal is very quick in call so >>>> we should not do large operation inside that slot because for >>>> downloading >>>> big data it may possible of frequent call of those signals which may >>>> cause >>>> the crash or missing data to write inside the file so removed >>>> unnecessary >>>> logic from that slot. >>>> - Fixed the crash while opening IODevice with NULL handle. >>>> >>>> With above changes, I have tested with same data as earlier and it is >>>> working as expected without crashing the application. >>>> >>>> Do review it and let me know for comments. >>>> >>> >> My first test was on Mac using Qt 5.8 with webkit, and when I attempted >> to download the results from a 300K row query, it basically hung showing >> the Downloading File progress indicator. It let me cancel it and carried on >> working, but hung again the next time I tried the CSV download. Each time >> it seems to download some data - from the same query I've seen 2.8MB, 5.1MB >> and 1.5MB. >> > > We are using "*downloadProgress*" signal to update the progress bar and > here we are getting "readData" as bytes but "totalData" is unknown so we > received "totalData" as -1 because Qt doesn't know the total size of the > file we are getting from server but when we open "pgAdmin4" website in > another link and try to download some binary or source at that time we are > getting "totalData" as known size and we are displaying the progress bar > correctly. > > Here, Qt sending the signal "downloadProgress" with unknown totalData size > as -1 so we update the progress bar with 100% so from user point of view it > looks like hang but it is downloading and writing to file at back ground. > if we apply the same patch in windows then it display running progress bar > so user can know something happening at back end side. > > I think it is same as browser - if we download big size file from server > then it keep on downloading the file without displaying total size. What > should we do here ? Should we create one custom progress bar dialog with > moving cursor or something other so that user can know that activity is > doing at backend ? Thoughts ? > It is misleading, but it *is* also hanging. 10+ minutes to download a few megs of data from a server on the same machine is not just a misleading progress indicator :-) -- Dave Page Blog: http://pgsnake.blogspot.com Twitter: @pgsnake EnterpriseDB UK: http://www.enterprisedb.com The Enterprise PostgreSQL Company
