Decode each attachment once in extract_attachments - #7
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Mail#decoded does not memoize (mail-2.9.0 message.rb:1893) — it base64-decodes into a new String on every call. extract_attachments called it twice per attachment, once for the upload body and again for `size:`, allocating the full attachment twice. Measured on ruby:3.4.9-slim under a 384Mi limit with a 34.4MB message (25MB attachment), peak cgroup memory for a single request drops 255.5MB -> 195.2MB, and RSS retained after two concurrent requests drops 125.4MB -> 75.4MB. This does not fix the OOMKills: at 2 concurrent requests peak is unchanged (324.4MB -> 323.9MB) because other copies dominate there, and 3 concurrent requests still exit 137. The remaining cause is that the whole message is held in memory (raw + parsed + decoded) while puma allows 5 concurrent threads. get_message had no test coverage at all, which is how this went unnoticed; add specs for the attachment metadata and a guard asserting a single decode per attachment. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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Mail#decoded does not memoize (mail-2.9.0 message.rb:1893) — it
base64-decodes into a new String on every call. extract_attachments called
it twice per attachment, once for the upload body and again for
size:, allocating the full attachment twice.Measured on ruby:3.4.9-slim under a 384Mi limit with a 34.4MB message
(25MB attachment), peak cgroup memory for a single request drops
255.5MB -> 195.2MB, and RSS retained after two concurrent requests drops
125.4MB -> 75.4MB.
This does not fix the OOMKills: at 2 concurrent requests peak is
unchanged (324.4MB -> 323.9MB) because other copies dominate there, and 3
concurrent requests still exit 137. The remaining cause is that the whole
message is held in memory (raw + parsed + decoded) while puma allows 5
concurrent threads.
get_message had no test coverage at all, which is how this went unnoticed;
add specs for the attachment metadata and a guard asserting a single
decode per attachment.
Co-Authored-By: Claude Opus 5 (1M context) noreply@anthropic.com