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Type: Bug
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Resolution: Done
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Priority: Critical - P2
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Affects Version/s: 2.8.0-rc0
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Component/s: Performance, Storage
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Fully Compatible
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ALL
Seeing severe performance issue in capped collections.
- drop-off of couple orders of magnitude in insertion rate apparently around the point where the collection size limit is reached (about 450k docs in this example).
- insertion rate appears to continue to decline
- compression does not matter
- lsm is worse than record store
inserts/s after n docs:
n mmapv1 wt wt wt rec str rec str lsm snappy no comp snappy 10000 48076 39062 39215 38314 20000 52083 40816 39370 37735 30000 50505 39062 39682 38461 40000 52356 40322 38910 37878 50000 52356 36630 37174 35971 ... 400000 37313 37313 37174 32258 410000 38022 40485 38610 33112 420000 37037 42016 40650 35335 430000 35971 39370 39370 31347 440000 37037 38314 39525 34013 450000 38461 38314 38167 33670 460000 37593 19920 20449 3943 470000 38022 5396 6020 592 480000 38610 2217 1959 275 490000 38167 1140 1150 229 500000 37313 832 829 169
function create(size) { db.createCollection("c", {capped: true, size: size}) } function insert(count) { var every = 10000 var bulk = db.c.initializeUnorderedBulkOp(); var t = new Date() for (var i=0; i<=count; i++) { if (i>0 && i%every==0) { bulk.execute(); bulk = db.c.initializeUnorderedBulkOp(); tt = new Date() print(i, Math.floor(every / (tt-t) * 1000)) t = tt } bulk.insert({}) } } create(10000000) insert(500000)
- related to
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SERVER-16775 Steady decline in performance in capped collections under wiredTiger
- Closed
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SERVER-16247 Oplog declines in performance over time under WiredTiger
- Closed
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SERVER-16296 Producer-consumer use case shows declining performance over time under WIredTiger
- Closed