Spill SharedTLog when there's more than one. #2029
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When switching between spill_type or log_version, a new instance of a SharedTLog is created in the transaction log processes. If this is done in a saturated database, then doubling the amount of memory to hold mutations in memory can cause TLogs to be uncomfortably close to the 8GB OOM limit. Instead, we now thread which UID of a SharedTLog is active, and the other TLog spill out the majority of their mutations.
| if (activeSharedTLog->get() != tlogId) { | ||
| // TODO: This should fully spill, but currently doing so will cause us to no longer update poppedVersion | ||
| // and QuietDatabase will hang thinking our TLog is behind. | ||
| self->targetVolatileBytes = SERVER_KNOBS->REFERENCE_SPILL_UPDATE_STORAGE_BYTE_LIMIT * 2; |
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If you care enough about this, I'll go hunt down why this is happening, but I'm not sure I'm super concerned about reclaiming the extra 20MB in this rare case.
xumengpanda
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Sep 24, 2019
xumengpanda
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Sep 24, 2019
Whitespace fixes
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I ended up rebasing this on top of my current patch set which adds a new TLog version, and the ASSERT that I added to ensure that an active TLog wasn't set to aggressively spill actually did find a bug. I'll re-post this PR momentarily against master, and then backport it to release-6.2 once it's in. |
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When switching between spill_type or log_version, a new instance of a
SharedTLog is created in the transaction log processes. If this is done
in a saturated database, then doubling the amount of memory to hold
mutations in memory can cause TLogs to be uncomfortably close to the 8GB
OOM limit.
Instead, we now thread which UID of a SharedTLog is active, and the
other TLog spill out the majority of their mutations.