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Posted to server-dev@james.apache.org by rc...@apache.org on 2019/11/25 10:47:38 UTC
[james-project] 01/02: JAMES-2919 ADRs for JMAP-draft GetMessages
partial reads
This is an automated email from the ASF dual-hosted git repository.
rcordier pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/james-project.git
commit 11cc859752560bab52db76c2b3fb57531f40ce4b
Author: Benoit Tellier <bt...@linagora.com>
AuthorDate: Thu Oct 17 09:27:43 2019 +0700
JAMES-2919 ADRs for JMAP-draft GetMessages partial reads
---
src/adr/0012-jmap-partial-reads.md | 40 +++++++++++++++++++++++++++
src/adr/0013-precompute-jmap-preview.md | 48 +++++++++++++++++++++++++++++++++
2 files changed, 88 insertions(+)
diff --git a/src/adr/0012-jmap-partial-reads.md b/src/adr/0012-jmap-partial-reads.md
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+# 12. Projections for JMAP Messages
+
+Date: 2019-10-09
+
+## Status
+
+Proposed
+
+Adoption needs to be backed by some performance tests.
+
+## Context
+
+JMAP core RFC8620 requires that the server responds only properties requested by the client.
+
+James currently computes all of the properties regardless of their cost, and if it had been asked by the client.
+
+Clearly we can save some latencies and resources by avoiding reading/computing expensive properties that had not been explicitly requested by the client.
+
+## Decision
+
+Introduce two new datastructures representing JMAP messages:
+ - One with only metadata
+ - One with metadata + headers
+
+Given the properties requested by the client, the most appropriate message datastructure will be computed, on top of
+existing message storage APIs that should remain unchanged.
+
+Some performance tests will be run in order to evaluate the improvements.
+
+## Consequences
+
+GetMessages with a limited set of requested properties will no longer result necessarily in full database message read. We
+thus expect a significant improvement, for instance when only metadata are requested.
+
+In case of a less than 5% improvement, the code will not be added to the codebase and the proposal will get the status 'rejected'.
+
+## References
+
+ - /get method: https://tools.ietf.org/html/rfc8620#section-5.1
+ - [JIRA](https://issues.apache.org/jira/browse/JAMES-2919)
diff --git a/src/adr/0013-precompute-jmap-preview.md b/src/adr/0013-precompute-jmap-preview.md
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+++ b/src/adr/0013-precompute-jmap-preview.md
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+# 13. Precompute JMAP Email preview
+
+Date: 2019-10-09
+
+## Status
+
+Proposed
+
+Adoption needs to be backed by some performance tests.
+
+## Context
+
+JMAP messages have a handy preview property displaying the firsts 256 characters of meaningful test of a message.
+
+This property is often displayed for message listing in JMAP clients, thus it is queried a lot.
+
+Currently, to get the preview, James retrieves the full message body, parse it using MIME parsers, removes HTML and keep meaningful text.
+
+## Decision
+
+We should pre-compute message preview.
+
+A MailboxListener will compute the preview and store it in a MessagePreviewStore.
+
+We should have a Cassandra and memory implementation.
+
+When the preview is precomputed then for these messages we can consider the "preview" property as a metadata.
+
+When the preview is not precomputed then we should compute the preview for these messages, and save the result for later.
+
+We should provide a webAdmin task allowing to rebuild the projection. The computing and storing in MessagePreviewStore
+is idempotent and the task can be run in live without any concurrency problem.
+
+Some performance tests will be run in order to evaluate the improvements.
+
+## Consequences
+
+We expect a huge performance enhancement for JMAP clients relying on preview for listing mails.
+
+In case of a less than 5% improvement, the code will not be added to the codebase and the proposal will get the status 'rejected'.
+
+## References
+
+ - https://jmap.io/server.html#1-emails JMAP client guice states that preview needs to be quick to retrieve
+
+ - Similar decision had been taken at FastMail: https://fastmail.blog/2014/12/15/dec-15-putting-the-fast-in-fastmail-loading-your-mailbox-quickly/
+
+ - [JIRA](https://issues.apache.org/jira/browse/JAMES-2919)
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