Eungsop Yoo created HBASE-29039:
-----------------------------------
Summary: Optimize read performance for accumulated delete markers
on the same row or cell
Key: HBASE-29039
URL: https://issues.apache.org/jira/browse/HBASE-29039
Project: HBase
Issue Type: Improvement
Affects Versions: 2.5.10, 2.6.1
Reporter: Eungsop Yoo
As delete markers are accumulated on the same row or cell, Get opertions slow
down. It can be reproduced by follow HBase shell commands.
{code}
create 'test', 'c'
java_import org.apache.hadoop.hbase.client.Delete
java_import org.apache.hadoop.hbase.TableName
java_import java.lang.System
con = @hbase.instance_variable_get(:@connection)
table = con.getTable(TableName.valueOf('test'))
1000.times do |i|
# batch 10000 deletes with different timestamps every 10 seconds
now = System.currentTimeMillis()
dels = 10000.times.map do |i|
del = Delete.new(Bytes.toBytes('row'))
del.addFamily(Bytes.toBytes('c'), now + i)
end
table.delete(dels)
sleep(10)
puts "i - #{i}"
get 'test', 'row'
end
{code}
{code}
i - 0
COLUMN
CELL
0 row(s)
Took 0.0251 seconds
...
i - 10
COLUMN
CELL
0 row(s)
Took 0.0412 seconds
...
i - 20
COLUMN
CELL
0 row(s)
Took 0.0760 seconds
...
i - 30
COLUMN
CELL
0 row(s)
Took 0.1014 seconds
...
i - 40
COLUMN
CELL
0 row(s)
Took 0.1616 seconds
...
{code}
But the performance of Get operations can be optimized by using SEEK_NEXT_COL.
{code}
i - 1
COLUMN
CELL
0 row(s)
Took 0.0087 seconds
...
i - 11
COLUMN
CELL
0 row(s)
Took 0.0077 seconds
...
i - 21
COLUMN
CELL
0 row(s)
Took 0.0087 seconds
...
{code}
Please review the PR.
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