Yngve Kristiansen created ARROW-5274: ----------------------------------------
Summary: [Javascript] Wrong array type for countBy Key: ARROW-5274 URL: https://issues.apache.org/jira/browse/ARROW-5274 Project: Apache Arrow Issue Type: Bug Reporter: Yngve Kristiansen The {{countBy}} function is not returning correct histograms, as it seems to select the wrong array type for the indexing. The following line in countBy seems to be causing the problems: {{const countByteLength = Math.ceil(Math.log(vector.dictionary.length) / Math.log(256));}} For example, if the dictionary length is 3, yet the indices length is 1 million, the result of this expression will be 1, which will lead to a Uint8Array being used, again resulting in overflows. Codepen example [https://codepen.io/Yngve92/pen/mYdWrr] If I switch the expression to: {{const countByteLength = Math.ceil(Math.log(vector.length) / Math.log(256));}} it seems to be working all right, but I am not sure if this is correct. The expression is on L63, L189 in src/compute/dataframe.ts. -- This message was sent by Atlassian JIRA (v7.6.3#76005)