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Revision d3d20dcdca9dc79d893a03dfa611fb1055c28f96 authored by Sagar Vemuri on 11 April 2019, 02:24:25 UTC, committed by Facebook Github Bot on 11 April 2019, 02:31:18 UTC 
Periodic Compactions (#5166)
 
Summary:
Introducing Periodic Compactions.

This feature allows all the files in a CF to be periodically compacted. It could help in catching any corruptions that could creep into the DB proactively as every file is constantly getting re-compacted.  And also, of course, it helps to cleanup data older than certain threshold.

- Introduced a new option `periodic_compaction_time` to control how long a file can live without being compacted in a CF.
- This works across all levels.
- The files are put in the same level after going through the compaction. (Related files in the same level are picked up as `ExpandInputstoCleanCut` is used).
- Compaction filters, if any, are invoked as usual.
- A new table property, `file_creation_time`, is introduced to implement this feature. This property is set to the time at which the SST file was created (and that time is given by the underlying Env/OS).

This feature can be enabled on its own, or in conjunction with `ttl`. It is possible to set a different time threshold for the bottom level when used in conjunction with ttl. Since `ttl` works only on 0 to last but one levels, you could set `ttl` to, say, 1 day, and `periodic_compaction_time` to, say, 7 days. Since `ttl < periodic_compaction_time` all files in last but one levels keep getting picked up based on ttl, and almost never based on periodic_compaction_time. The files in the bottom level get picked up for compaction based on `periodic_compaction_time`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5166

Differential Revision: D14884441

Pulled By: sagar0

fbshipit-source-id: 408426cbacb409c06386a98632dcf90bfa1bda47
1 parent ef0fc1b
Raw File
generate_random_db.sh 
#!/usr/bin/env bash
#
# A shell script to load some pre generated data file to a DB using ldb tool
# ./ldb needs to be avaible to be executed.
#
# Usage: <SCRIPT> <input_data_path> <DB Path>

if [ "$#" -lt 2 ]; then
  echo "usage: $BASH_SOURCE <input_data_path> <DB Path>"
  exit 1
fi

input_data_dir=$1
db_dir=$2
rm -rf $db_dir

echo == Loading data from $input_data_dir to $db_dir

declare -a compression_opts=("no" "snappy" "zlib" "bzip2")

set -e

n=0

for f in `ls -1 $input_data_dir`
do
  echo == Loading $f with compression ${compression_opts[n % 4]}
  ./ldb load --db=$db_dir --compression_type=${compression_opts[n % 4]} --bloom_bits=10 --auto_compaction=false --create_if_missing < $input_data_dir/$f
  let "n = n + 1"
done
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