Summary:
…in order
This fixes https://github.com/facebook/rocksdb/issues/9650
For db_bench --benchmarks=fillseq --num_multi_db=X it loads databases in sequence
rather than randomly choosing a database per Put. The benefits are:
1) avoids long delays between flushing memtables
2) avoids flushing memtables for all of them at the same point in time
3) puts same number of keys per database so that query tests will find keys as expected
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9713
Test Plan:
Using db_bench.1 without the change and db_bench.2 with the change:
for i in 1 2; do rm -rf /data/m/rx/* ; time ./db_bench.$i --db=/data/m/rx --benchmarks=fillseq --num_multi_db=4 --num=10000000; du -hs /data/m/rx ; done
--- without the change
fillseq : 3.188 micros/op 313682 ops/sec; 34.7 MB/s
real 2m7.787s
user 1m52.776s
sys 0m46.549s
2.7G /data/m/rx
--- with the change
fillseq : 3.149 micros/op 317563 ops/sec; 35.1 MB/s
real 2m6.196s
user 1m51.482s
sys 0m46.003s
2.7G /data/m/rx
Also, temporarily added a printf to confirm that the code switches to the next database at the right time
ZZ switch to db 1 at 10000000
ZZ switch to db 2 at 20000000
ZZ switch to db 3 at 30000000
for i in 1 2; do rm -rf /data/m/rx/* ; time ./db_bench.$i --db=/data/m/rx --benchmarks=fillseq,readrandom --num_multi_db=4 --num=100000; du -hs /data/m/rx ; done
--- without the change, smaller database, note that not all keys are found by readrandom because databases have < and > --num keys
fillseq : 3.176 micros/op 314805 ops/sec; 34.8 MB/s
readrandom : 1.913 micros/op 522616 ops/sec; 57.7 MB/s (99873 of 100000 found)
--- with the change, smaller database, note that all keys are found by readrandom
fillseq : 3.110 micros/op 321566 ops/sec; 35.6 MB/s
readrandom : 1.714 micros/op 583257 ops/sec; 64.5 MB/s (100000 of 100000 found)
Reviewed By: jay-zhuang
Differential Revision: D35030168
Pulled By: mdcallag
fbshipit-source-id: 2a18c4ec571d954cf5a57b00a11802a3608823ee
63a284a6ad