html_url,issue_url,id,node_id,user,created_at,updated_at,author_association,body,reactions,performed_via_github_app,issue
https://github.com/pydata/xarray/issues/3484#issuecomment-550471849,https://api.github.com/repos/pydata/xarray/issues/3484,550471849,MDEyOklzc3VlQ29tbWVudDU1MDQ3MTg0OQ==,4605410,2019-11-06T19:48:17Z,2019-11-06T19:48:17Z,NONE,"@friedrichknuth One of my motivations behind exploring sparse DataArray backends is in reducing the memory footprint during merge operations. Consider the following:

<a href=""https://www.codecogs.com/eqnedit.php?latex=\begin{Vmatrix}&space;X_{11}(t)&space;&&space;X_{12}(t))\\&space;\end{Vmatrix}&space;\textbf{merge&space;with}&space;\begin{Vmatrix}&space;X_{22}(t)&space;&&space;X_{23}(t))\\&space;\end{Vmatrix}&space;=&space;\begin{Vmatrix}&space;X_{11}(t)&space;&&space;X_{12}(t)&space;&&space;\textbf{NaN/0}\\&space;\textbf{NaN/0}&space;&&space;X_{22}(t)&space;&&space;X_{23}(t)&space;\end{Vmatrix}"" target=""_blank""><img src=""https://latex.codecogs.com/gif.latex?\begin{Vmatrix}&space;X_{11}(t)&space;&&space;X_{12}(t))\\&space;\end{Vmatrix}&space;\textbf{merge&space;with}&space;\begin{Vmatrix}&space;X_{22}(t)&space;&&space;X_{23}(t))\\&space;\end{Vmatrix}&space;=&space;\begin{Vmatrix}&space;X_{11}(t)&space;&&space;X_{12}(t)&space;&&space;\textbf{NaN/0}\\&space;\textbf{NaN/0}&space;&&space;X_{22}(t)&space;&&space;X_{23}(t)&space;\end{Vmatrix}"" title=""\begin{Vmatrix} X_{11}(t) & X_{12}(t))\\ \end{Vmatrix} \textbf{merge with} \begin{Vmatrix} X_{22}(t) & X_{23}(t))\\ \end{Vmatrix} = \begin{Vmatrix} X_{11}(t) & X_{12}(t) & \textbf{NaN/0}\\ \textbf{NaN/0} & X_{22}(t) & X_{23}(t) \end{Vmatrix}"" /></a>

One can imagine many such merge operations producing a lot of effectively empty indices. While sparse backed arrays might have the ability to condense these empty indices in memory, it seems like [xarray sparse merging isnt quite compatible yet.](https://github.com/pydata/xarray/issues/3445#issue-512205079)","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,517338735