REP-6832 Always read latest-possible version of documents #177
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visemet
requested changes
Nov 18, 2025
| // or for the last generation, the change stream end time. | ||
| cmd = append( | ||
| cmd, | ||
| bson.E{"readConcern", bson.D{ |
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As we discussed on Slack in #go-driver channel, RunCommandCursor() will not use the read concern set on the MongoClient. Using read concern level "majority" must be set here explicitly.
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OK. My takeaway from that thread was, “status quo is correct” … but it seems that that’s not actually the case.
| Int("count", len(docIDs)). | ||
| Any("latestTimestamp", latestTimestamp). | ||
| Time("latestTimestampTime", latestTimestampTime). | ||
| Stringer("lag", lag). |
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[question] What is the motivation for "lag" in the output here getting removed? I understand it is the only usage of changeEventBatch.clusterTime.
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It’s redundant with the lag that gets printed anyway in the logs’ periodic progress reports.
visemet
approved these changes
Nov 19, 2025
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This improves the prevention of stale reads to incorporate the latest-seen cluster time and to use majority read concern.
This is particularly relevant when reading from secondaries, but it can also, because of SERVER-53813, affect reads from primaries.
This removes a
lagfrom a trace-level log in order to simplify things a bit. That data point is redundant with the periodically-reported lag in the logs anyway.