Data processing with Elixir (Part 1)

CREATE TABLE github_events
(
    file_time DateTime,
    event_type Enum('CommitCommentEvent' = 1, 'CreateEvent' = 2, 'DeleteEvent' = 3, 'ForkEvent' = 4,
                    'GollumEvent' = 5, 'IssueCommentEvent' = 6, 'IssuesEvent' = 7, 'MemberEvent' = 8,
                    'PublicEvent' = 9, 'PullRequestEvent' = 10, 'PullRequestReviewCommentEvent' = 11,
                    'PushEvent' = 12, 'ReleaseEvent' = 13, 'SponsorshipEvent' = 14, 'WatchEvent' = 15,
                    'GistEvent' = 16, 'FollowEvent' = 17, 'DownloadEvent' = 18, 'PullRequestReviewEvent' = 19,
                    'ForkApplyEvent' = 20, 'Event' = 21, 'TeamAddEvent' = 22),
    actor_login LowCardinality(String),
    repo_name LowCardinality(String),
    created_at DateTime,
    updated_at DateTime,
    action Enum('none' = 0, 'created' = 1, 'added' = 2, 'edited' = 3, 'deleted' = 4, 'opened' = 5, 'closed' = 6, 'reopened' = 7, 'assigned' = 8, 'unassigned' = 9,
                'labeled' = 10, 'unlabeled' = 11, 'review_requested' = 12, 'review_request_removed' = 13, 'synchronize' = 14, 'started' = 15, 'published' = 16, 'update' = 17, 'create' = 18, 'fork' = 19, 'merged' = 20),
    comment_id UInt64,
    body String,
    path String,
    position Int32,
    line Int32,
    ref LowCardinality(String),
    ref_type Enum('none' = 0, 'branch' = 1, 'tag' = 2, 'repository' = 3, 'unknown' = 4),
    creator_user_login LowCardinality(String),
    number UInt32,
    title String,
    labels Array(LowCardinality(String)),
    state Enum('none' = 0, 'open' = 1, 'closed' = 2),
    locked UInt8,
    assignee LowCardinality(String),
    assignees Array(LowCardinality(String)),
    comments UInt32,
    author_association Enum('NONE' = 0, 'CONTRIBUTOR' = 1, 'OWNER' = 2, 'COLLABORATOR' = 3, 'MEMBER' = 4, 'MANNEQUIN' = 5),
    closed_at DateTime,
    merged_at DateTime,
    merge_commit_sha String,
    requested_reviewers Array(LowCardinality(String)),
    requested_teams Array(LowCardinality(String)),
    head_ref LowCardinality(String),
    head_sha String,
    base_ref LowCardinality(String),
    base_sha String,
    merged UInt8,
    mergeable UInt8,
    rebaseable UInt8,
    mergeable_state Enum('unknown' = 0, 'dirty' = 1, 'clean' = 2, 'unstable' = 3, 'draft' = 4),
    merged_by LowCardinality(String),
    review_comments UInt32,
    maintainer_can_modify UInt8,
    commits UInt32,
    additions UInt32,
    deletions UInt32,
    changed_files UInt32,
    diff_hunk String,
    original_position UInt32,
    commit_id String,
    original_commit_id String,
    push_size UInt32,
    push_distinct_size UInt32,
    member_login LowCardinality(String),
    release_tag_name String,
    release_name String,
    review_state Enum('none' = 0, 'approved' = 1, 'changes_requested' = 2, 'commented' = 3, 'dismissed' = 4, 'pending' = 5)
)
ENGINE = MergeTree
ORDER BY (event_type, repo_name, created_at)

~/tools/ch_may_23/clickhouse local -q "select c2, count(*) as cnt from file('github_events_a*', TabSeparated) group by c2"

tab_char = :binary.compile_pattern("\t") # BINARY

streams =
  for file <- File.ls!("/Users/parth/temp/github_events/clickhouse_tsv") do
    full_path = "/Users/parth/temp/github_events/clickhouse_tsv/#{file}"
    File.stream!(full_path, [{:read_ahead, 100_000}])
  end

streams
|> Task.async_stream(fn stream ->
  stream
  |> Stream.map(fn line ->
    line |> String.split(tab_char) |> Enum.at(1)
  end)
  |> Enum.reduce(%{}, fn event_type, acc ->
    Map.update(acc, event_type, 1, &(&1 + 1))
  end)
end, max_concurrency: 10, timeout: :infinity)
|> Enum.to_list()
|> Enum.flat_map(fn {_, mp} -> Map.to_list(mp) end)
|> Enum.reduce(%{}, fn {etype, count}, acc ->
  Map.update(acc, etype, count, &(&1 + count))
end)