Skip to content

remove the concept of virtual row groups #281

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
severo merged 1 commit into from
Jul 30, 2025
Merged

remove the concept of virtual row groups #281

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
39 changes: 17 additions & 22 deletions src/lib/tableProvider.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -12,7 +12,7 @@ type GroupStatus = {
} | {
kind: 'fetched'
}
interface VirtualRowGroup {
interface RowGroup {
groupStart: number
groupEnd: number
state: Map<string, GroupStatus>
Expand All @@ -28,29 +28,24 @@ export function parquetDataFrame(from: AsyncBufferFrom, metadata: FileMetaData):

const cellCache = new Map<string, ResolvedValue<unknown>[]>(header.map(name => [name, []]))

// virtual row groups are up to 1000 rows within row group boundaries
const groups: VirtualRowGroup[] = []
const rowGroups: RowGroup[] = []
let groupStart = 0
for (const rg of metadata.row_groups) {
// make virtual row groups of size 1000
for (let j = 0; j < rg.num_rows; j += 1000) {
const groupSize = Math.min(1000, Number(rg.num_rows) - j)
const groupEnd = groupStart + groupSize
groups.push({
groupStart,
groupEnd,
state: new Map(header.map(name => [name, { kind: 'unfetched' }])),
})
groupStart = groupEnd
}
const groupEnd = groupStart + Number(rg.num_rows)
rowGroups.push({
groupStart,
groupEnd,
state: new Map(header.map(name => [name, { kind: 'unfetched' }])),
})
groupStart = groupEnd
}

async function fetchVirtualRowGroup({ group, columns }: {
group: VirtualRowGroup, columns: string[]
async function fetchRowGroup({ rowGroup, columns }: {
rowGroup: RowGroup, columns: string[]
}): Promise<void> {
const { groupStart, groupEnd, state } = group
const { groupStart, groupEnd, state } = rowGroup
const columnsToFetch = columns.filter(column => state.get(column)?.kind === 'unfetched')
const promises = [...group.state.values()].filter((status): status is { kind: 'fetching', promise: Promise<void> } => status.kind === 'fetching').map(status => status.promise)
const promises = [...rowGroup.state.values()].filter((status): status is { kind: 'fetching', promise: Promise<void> } => status.kind === 'fetching').map(status => status.promise)

// TODO(SL): pass AbortSignal to the worker?
if (columnsToFetch.length > 0) {
Expand Down Expand Up @@ -107,12 +102,12 @@ export function parquetDataFrame(from: AsyncBufferFrom, metadata: FileMetaData):

const promises: Promise<void>[] = []

groups.forEach((group) => {
const { groupStart, groupEnd } = group
rowGroups.forEach((rowGroup) => {
const { groupStart, groupEnd } = rowGroup
if (groupStart < rowEnd && groupEnd > rowStart) {
promises.push(
fetchVirtualRowGroup({
group,
fetchRowGroup({
rowGroup,
columns,
}).then(() => {
checkSignal(signal)
Expand Down