Grid performance with lots of columns

[vaadin-bot]

Originally by fschmitt

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I used the Grid component to build a tabular with lots of columns, where columns represent days in a date interval. Additionally I grouped header columns to represent calendar weeks per year and months.
Sadly I noticed, that the initial loading performance is not really satisfying.
I simulated my implementation and will attach it to this ticket.

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Imported from https://dev.vaadin.com/ issue #16474

[vaadin-bot]

Originally by fschmitt

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Attachment added: BigGridTest.java (1.7 KiB)
Test implementation

[vaadin-bot]

Originally by fschmitt

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With my setting its around 5 seconds until I can see the grid and another 5 seconds until the grid is correctly rendered

[vaadin-bot]

Originally by @jdahlstrom

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Hi, thanks for the report. The client-side Grid does currently a lot of unnecessary work when adding multiple columns at a time (including during the initialization phase), and we're in process of optimizing the process. There are a couple of low-hanging fruits that should improve the performance quite a bit.

I should mention, though, that Grid is not especially designed for the case of lots of columns; the lack of column lazy loading in particular will be an issue as the number of columns grows.

[vaadin-bot]

Originally by @wolfie

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Initial benchmarks on my Retina Macbook Pro (OSX 10.10.1, Chrome 41.0.2272.16 beta (64-bit)) tells me that your provided example application spends 2.2 seconds in the Grid.onStateChange method (note: this doesn't account for everything makes Grid slow in your example), out of which roughly 2s was simply adding those 60 columns.

I have some initial enhancements that gets both of those times to 1.3s. I've identified another place that currently takes about 3.5s to run. If I'm lucky, I'll have the time to optimize this down to about 50% or so. It's in a hairy part of the code, so I'm not keeping my hopes up too high... I'll report back once I have something.

[vaadin-bot]

Originally by @wolfie

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I found a way to reduce overhead "a bit" when setting widths for multiple columns, getting the 3500ms down to 200ms on the 60 columns. I'll check the test results on how badly that might break the surrounding stuff...

So, from 6s on my machine, we're now down to about 1.5s. Once all tests pass, I think this will be enough for now, as getting it down further than this would require considerable changes to the architecture in general.

[vaadin-bot]

Originally by fschmitt

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Wow, thanks for the effort, that sounds promising! You think these changes will make it into 7.4 beta3?

[vaadin-bot]

Originally by @wolfie

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The patch is still in review (https://dev.vaadin.com/review/#/c/7072/), and beta3 is being built as we speak (i think), so I'm thinking "no", unfortunately. But it will most probably be in RC1.