[
https://issues.apache.org/jira/browse/HIVE-14450?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Gopal V updated HIVE-14450:
---------------------------
Description:
{code}
public static int truncate(byte[] bytes, int start, int length, int maxLength) {
int end = start + length;
// count characters forward
int j = start;
int charCount = 0;
while(j < end) {
// UTF-8 continuation bytes have 2 high bits equal to 0x80.
if ((bytes[j] & 0xc0) != 0x80) {
if (charCount == maxLength) {
break;
}
++charCount;
}
j++;
}
return (j - start);
}
{code}
Should not read the bytes if the maxLength is 4096 and the input string has 256
bytes.
was:
{code}
public static int truncate(byte[] bytes, int start, int length, int maxLength) {
int end = start + length;
// count characters forward
int j = start;
int charCount = 0;
while(j < end) {
// UTF-8 continuation bytes have 2 high bits equal to 0x80.
if ((bytes[j] & 0xc0) != 0x80) {
if (charCount == maxLength) {
break;
}
++charCount;
}
j++;
}
return (j - start);
}
{code}
Should not dirty the L1 cache if the maxLength is 4096 and the input string has
256 bytes.
> Vectorization: StringExpr::truncate() can assume 1 byte per-char minimum
> ------------------------------------------------------------------------
>
> Key: HIVE-14450
> URL: https://issues.apache.org/jira/browse/HIVE-14450
> Project: Hive
> Issue Type: Improvement
> Components: Vectorization
> Affects Versions: 2.2.0
> Reporter: Gopal V
>
> {code}
> public static int truncate(byte[] bytes, int start, int length, int
> maxLength) {
> int end = start + length;
> // count characters forward
> int j = start;
> int charCount = 0;
> while(j < end) {
> // UTF-8 continuation bytes have 2 high bits equal to 0x80.
> if ((bytes[j] & 0xc0) != 0x80) {
> if (charCount == maxLength) {
> break;
> }
> ++charCount;
> }
> j++;
> }
> return (j - start);
> }
> {code}
> Should not read the bytes if the maxLength is 4096 and the input string has
> 256 bytes.
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