Chat logs on disk

DataMind Oda saves a log of every chat as files on your computer. This page shows where those files live, how Oda names and keeps them, and how to back them up or read them. What a log contains and the rules for reading it are on Chat log format.

Where chat logs live

Oda keeps every chat under a single folder on the computer; this page calls it the log folder. Inside it, chats are grouped by the folder they work in, and every chat has a folder of its own. A chat with compression on looks like this:

<log folder>/
  --<working folder>--/
    <chat folder>/
      session.v4.jsonl.zstd

• Chats are grouped by the folder they work in; the group folder's name is wrapped in --, and a chat with no working folder sits in a group called _no-cwd.
• The chat folder's name is built from the chat's id, encoded so the id is safe as a folder name.

How log files are named and kept

• The oldest log format keeps the plain name session.jsonl. Later formats add their version to the name, as in session.v1.jsonl; the current format is v4.
• When Oda updates a log written by an older format, the new file is added beside the old one, so one chat can have several generations side by side.
• The newest generation is the chat's current state. Earlier generations stay as they were.

• Oda reads only files with these exact names. A renamed copy, such as session.v1.backup.jsonl, is not treated as a log.

The log folder and compression

• The log folder has no default. It is set for each installation, and every chat is saved under it.
• Compression is on by default. A compressed log is stored as a series of Zstandard frames with checksums, and its name ends in .zstd.
• With compression off, a log is plain text: one JSON object per line. You can open it in a text editor.
• A log folder keeps one form: all compressed or all plain. Oda refuses a log whose form does not match its folder instead of reading it wrongly.
• A chat reaches disk only after it first has content. A chat you never used leaves no files, even if Oda stops suddenly.

One writer at a time

Oda keeps each chat's log in order by allowing one writer per chat at a time.

• The rule holds across every copy of Oda running on the computer, not only inside one window.
• Reading a chat is never blocked by the writer.
• A lock ends with its process, so a crash or a normal close leaves no stuck lock.
• On some systems, a small file named session.lock marks the chat being written. If a chat stays locked because the process holding it cannot continue, removing this file frees the chat for the next writer. Do this only when you are sure that process will not write the chat again.

Back up and copy chats

To keep a backup, copy the whole log folder to a safe place.

• Every chat folder is self-contained, so a copy holds whole chats, and each chat's earlier generations copy with it.
• The newest file in a chat's folder is the chat's current state.
• To use a copy, keep the folder shape and the saved form: a log stays inside its chat's folder under its group, and a folder keeps one form, compressed or plain.
• Oda refuses a log that sits in the wrong place or the wrong form, and the message says which file it found. For a message you meet, see Chat log problems.
• If the same chat appears under more than one group, Oda refuses to choose between the copies. Keep the one you need, and remove the other with care.
• Nothing prunes logs automatically. Oda never removes or trims log files, and there is no delete-all action, so files stay until someone removes them.

Read a chat log

• With compression off, open a log in a text editor: each line is one JSON object.
• With the default compression, read the chat in Oda; the compressed form is built to be read by Oda.
• Do not edit a log file in another program. Oda checks the log files it opens and refuses one that changed outside Oda rather than guess.

Questions, answered

Where do I find my chat logs on this computer?

All chat logs live under one folder, the log folder set for your installation. Inside it, chats are grouped by the folder they work in, and every chat has a folder of its own. If you are not sure which folder was chosen, ask your DataMind OS administrator.

Why is there no log file for a chat I just created?

A chat reaches disk only after it first has content. Until the chat starts, Oda writes nothing for it, and a chat you never used leaves no files, even if Oda stops suddenly.

What do the file names mean, and why can one chat have several files?

session.jsonl is the oldest log format; later formats add their version, as in session.v4.jsonl, and the name ends in .zstd when compression is on. When Oda updates a log from an older format, the new file is added beside the old one, so a chat can have several generations side by side. The newest generation is the chat's current state, and Oda never renames, replaces or deletes the older ones.

How do I back up my chats?

Copy the whole log folder to a safe place. Every chat folder is self-contained and keeps the chat's earlier generations, so the copy holds everything. To use a copy, put it back keeping the folder shape and the saved form; Oda refuses a log that sits in the wrong place or form rather than read it wrongly.

Can I read a chat log myself?

With compression off, yes: the log is plain text, one JSON object per line. With the default compression, read the chat in Oda, because the compressed form is built to be read by Oda. What a log contains and the rules for reading it are on Chat log format.

Does Oda clean up old log files by itself?

No. Oda never removes or trims log files, older generations included, and there is no delete-all action. Log files stay until someone removes them, so keep backups of anything you need.

What is the session.lock file?

On some systems Oda keeps a small file named session.lock in a chat's folder while the chat is being written. The lock ends with its process, so a crash leaves no stuck lock. If a chat stays locked because the process holding it cannot continue, removing the file frees the chat for the next writer; do this only when you are sure that process will not write the chat again.

Should I edit a log file by hand?

No. Oda checks the log files it opens and refuses one that changed outside Oda rather than guess, so a hand edit can leave a chat that will not open. Back files up instead of editing them.