slackdump-sqlite3

name: slackdump-sqlite3 description: Guidance for querying a Slackdump SQLite3 database directly via the sqlite3 CLI. metadata: audience: general workflow: database

Querying Slackdump database with sqlite3

Use this skill when the Slackdump MCP and SQLite MCP are both unavailable and you must fall back to the sqlite3 command-line tool.

Locate the database

Look for slackdump.sqlite in the current directory or the archive directory. If multiple files exist, ask the user to choose one.

Read-only access

You must not run any UPDATE, DELETE, INSERT, DROP, CREATE, or other DML/DDL statements. Only SELECT and data-dictionary queries are permitted.

Useful pragmas

-- List all tables
.tables

-- Show schema for a table
.schema MESSAGE

Key tables

Chunk types (TYPES table)

Chunk types with (no table) are not implemented yet, but reserved for future implementation. You will not see those chunks in the database.

Thread messages

A MESSAGE row is a thread reply when PARENT_ID IS NOT NULL AND IS_PARENT = FALSE.

Note: thread-parent messages also have PARENT_ID set (equal to their own ID), so PARENT_ID IS NOT NULL alone matches both parents and replies. Use IS_PARENT = TRUE to select thread-parent messages, and IS_PARENT = FALSE AND PARENT_ID IS NOT NULL for replies only.

MESSAGE.ID vs MESSAGE.TS

MESSAGE.ID is not the Slack timestamp string. It is the timestamp converted to an int64 by stripping the dot: e.g. "1648085300.726649" → 1648085300726649.

Use MESSAGE.TS for the human-readable Slack timestamp (e.g. for display or for passing to get_thread).

DATA column — full JSON blob

Every entity table (MESSAGE, CHANNEL, S_USER, FILE, etc.) stores the complete Slack API JSON payload in a DATA column (stored as a blob). Columns like TS, PARENT_ID, IS_PARENT, MODE, NAME are extracted for indexing, but all other fields (reactions, edited timestamps, message subtypes, user profiles, etc.) are only accessible via SQLite's JSON_EXTRACT:

-- Example: get the subtype and reaction count of messages
SELECT TS,
       JSON_EXTRACT(DATA, '$.subtype') AS subtype,
       JSON_ARRAY_LENGTH(DATA, '$.reactions') AS reaction_count
FROM MESSAGE
WHERE CHUNK_ID = 44;

Fetching the latest version of a message

The same message (same MESSAGE.TS AND MESSAGE.CHANNEL_ID) can appear in multiple chunks and multiple sessions. There are two distinct reasons:

1. Multiple sessions — e.g. after a slackdump resume run the same message may be fetched again and stored in a newer session.
2. Multiple chunk types within the same session — a thread-starter message is stored twice in the same session: once under CHUNK.TYPE_ID=0 (channel history) and once under CHUNK.TYPE_ID=1 (thread messages).

Always scope your query to the correct chunk type first, then pick the latest session:

Latest Channel messages

• Use CHUNK.TYPE_ID = 0 when querying channel history messages.

-- Latest version of each channel-history message in a channel (TYPE_ID=0)
WITH LATEST AS (
    SELECT T.ID, MAX(CHUNK_ID) AS CHUNK_ID 
    FROM MESSAGE AS T 
    JOIN CHUNK AS CH ON CH.ID = T.CHUNK_ID
    WHERE 1=1 
    AND CH.TYPE_ID IN (0,1) 
    AND (
      T.CHANNEL_ID = [CHANNEL_ID]
      AND (
            ( CH.TYPE_ID=0 AND (CH.THREAD_ONLY=FALSE OR CH.THREAD_ONLY IS NULL)) 
         OR (CH.TYPE_ID=1 AND CH.THREAD_ONLY=TRUE AND T.IS_PARENT=TRUE)
         )
    )
    GROUP BY T.ID
)
SELECT T.ID,T.CHUNK_ID,T.CHANNEL_ID,T.TS,T.PARENT_ID,T.THREAD_TS,T.IS_PARENT,T.IDX,T.NUM_FILES,T.TXT,T.DATA,T.LATEST_REPLY
FROM LATEST L
JOIN MESSAGE AS T ON 1 = 1 AND T.ID = L.ID
 AND T.CHUNK_ID = L.CHUNK_ID JOIN CHUNK CH ON T.CHUNK_ID = CH.ID WHERE 1=1
ORDER BY T.ID;

Latest thread messages

• Use CHUNK.TYPE_ID = 1 when querying thread messages.

-- Latest version of each thread message in a thread (TYPE_ID=1)
WITH LATEST AS (
    SELECT T.ID, MAX(CHUNK_ID) AS CHUNK_ID
      FROM MESSAGE AS T
      JOIN CHUNK AS CH ON CH.ID = T.CHUNK_ID
    WHERE 1=1
      AND CH.TYPE_ID IN (0,1)
      AND (
            T.CHANNEL_ID = [CHANNEL_ID]
        AND T.PARENT_ID = [PARENT_MESSAGE_ID]
        AND ( JSON_EXTRACT(T.DATA, '$.subtype') IS NULL OR (JSON_EXTRACT(T.DATA, '$.subtype') = 'thread_broadcast' AND CH.TYPE_ID = 1 )   )
      )
    GROUP BY T.ID
)
SELECT T.ID,T.CHUNK_ID,T.CHANNEL_ID,T.TS,T.PARENT_ID,T.THREAD_TS,T.IS_PARENT,T.IDX,T.NUM_FILES,T.TXT,T.DATA,T.LATEST_REPLY
  FROM LATEST L
  JOIN MESSAGE AS T ON 1 = 1 AND T.ID = L.ID
   AND T.CHUNK_ID = L.CHUNK_ID JOIN CHUNK CH ON T.CHUNK_ID = CH.ID WHERE 1=1
ORDER BY T.ID

Ignore V_* views

Other views prefixed with V_ are internal to slackdump and track unprocessed threads during execution. Do not rely on them for analysis.