Problem

For organizations with thousands of Slack channels, the -member-only flag is extremely slow because it still fetches ALL workspace channels before filtering.

Real-world test evidence

Ran a test with -member-only flag on an enterprise workspace:

time slackdump archive -member-only -time-from "2025-01-20" -time-to "2025-01-21" -o test_member_archive

Result: After 6+ minutes, the command was still iterating through ALL workspace channels (not member channels). The output showed sequential channel IDs being processed one by one:

• C02FSNK0807
• C02FSRGPJH5
• C02GAC06DTR
• C02GJAMV6LE
• ... hundreds more non-member channels

The command was cancelled after 6 minutes - it was nowhere near complete.

Comparison:

Root Cause

The Edge client's GetConversationsContext() in internal/edge/slacker.go runs three parallel operations:

var pipeline = []func(){
    func() {
        // getting client.userBoot information (FAST - YOUR channels only)
        ub, err := cl.ClientUserBoot(ctx)
        // ...
    },
    func() {
        // collecting the IMs (FAST - YOUR DMs only)
        ims, err := cl.IMList(ctx)
        // ...
    },
    func() {
        // collecting the channels (SLOW - ALL workspace channels!)
        ch, err := cl.SearchChannels(ctx, "")  // <-- THE BOTTLENECK
        // ...
    },
}

The SearchChannels(ctx, "") call in internal/edge/search.go:85 has SearchOnlyMyChannels: false, causing it to paginate through EVERY channel in the workspace.

The -member-only flag only filters results AFTER all channels are fetched (internal/chunk/control/processors.go:158):

if c.memberOnly && (ch.ID[0] == 'C' && !ch.IsMember) {
    // skip public non-member channels
    continue
}

Evidence: Fast Endpoints Already Exist

The Edge API already provides fast endpoints that return only the user's channels:

client.userBoot endpoint

• Returns all channels the user is a member of with full metadata
• Single API call, returns instantly
• Tested: Returns 418 channels for a user in a workspace with thousands of channels

client.counts endpoint

• Returns channels with activity metadata: Latest timestamp, HasUnreads, MentionCount
• Single API call
• Tested: Returns 198 channels with activity data

Test script results (same workspace)

ClientCounts returned 85 channels + 68 DMs + 45 MPIMs = 198 total (FAST)
ClientUserBoot returned 418 channels (with full metadata)

Both calls complete in under 1 second. The current -member-only implementation takes 6+ minutes and still doesn't finish.

Proposed Solution

When -member-only is specified, skip the slow SearchChannels("") call entirely. The data from ClientUserBoot() already contains all member channels with full metadata including:

• Channel ID, name, archived status
• IsMember flag (always true since it only returns member channels)
• Topic, purpose, creator
• Members list

Implementation approach

In internal/edge/slacker.go, modify GetConversationsContext() to accept a "member-only" parameter. When true:

1. Skip the SearchChannels(ctx, "") goroutine entirely
2. Rely only on ClientUserBoot() and IMList() which already return member channels

Alternatively, the SearchChannels function already has a SearchOnlyMyChannels field (line 53 in search.go) that could be set to true for member-only mode, but skipping the call entirely would be even faster.

Additional Enhancement: Activity-based filtering

The ClientCounts() endpoint returns activity metadata that could enable powerful new filtering options:

type ChannelSnapshot struct {
    ID           string
    LastRead     fasttime.Time  // When user last read the channel
    Latest       fasttime.Time  // Timestamp of latest message  
    MentionCount int            // Unread @mentions
    HasUnreads   bool           // Has unread messages
}

This could enable flags like:

• --with-activity - Only channels with any activity
• --activity-since DATE - Only channels with messages since a date
• --with-mentions - Only channels with unread @mentions

Use Case

Daily export scripts that archive Slack conversations. Currently users must either:

1. Hardcode channel IDs (tedious, misses new channels)
2. Use -member-only which is too slow for large workspaces (6+ minutes and counting)
3. Wait for the full channel list to complete

With fast member-only mode, users could efficiently archive all their channels without specifying each one manually.