cuijianwei created HBASE-14397:
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Summary: PrefixFilter fail to filter all remainings if the prefix
is longer than compared rowkey
Key: HBASE-14397
URL: https://issues.apache.org/jira/browse/HBASE-14397
Project: HBase
Issue Type: Improvement
Components: Filters
Affects Versions: 2.0.0
Reporter: cuijianwei
Priority: Minor
The PrefixFilter will filter rowkey as:
{code}
public boolean filterRowKey(Cell firstRowCell) {
...
int length = firstRowCell.getRowLength();
if (length < prefix.length) return true; // ===> return directly if the
prefix is longer
....
if ((!isReversed() && cmp > 0) || (isReversed() && cmp < 0)) {
passedPrefix = true;
}
filterRow = (cmp != 0);
return filterRow;
}
{code}
If the prefix is longer than the current rowkey, PrefixFilter#filterRowKey will
filter the rowkey directly without comparing, so that won't set 'passedPrefix'
flag even the current row is larger than the prefix.
For example, if there are three rows 'a', 'b' and 'c' in the table, and we
issue a scan request as:
{code}
hbase(main):001:0> scan 'test_table', {STARTROW => 'a', FILTER =>
"(PrefixFilter ('aa'))"}
{code}
The region server will check the three rows before returning. In our
production, the user issue a scan with a PrefixFilter. The prefix is longer
than the rowkeys of following millions of rows, so the region server will
continue to check rows until hit a rowkey longer than the prefix. This make the
client easily timeout. To fix this case, it seems we need to compare the prefix
with the rowkey even when the prefix is longer.
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