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https://issues.apache.org/jira/browse/IMPALA-12373?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Zoltán Borók-Nagy updated IMPALA-12373:
---------------------------------------
Description:
Implement Small String Optimization for StringValue.
Current memory layout of StringValue is:
{noformat}
char* ptr; // 8 byte
int len; // 4 byte
{noformat}
For small strings with size up to 8 we could store the string contents in the
bytes of the 'ptr'. Something like that:
{noformat}
union {
char* ptr;
char small_buf[sizeof(ptr)];
}
int len;
{noformat}
Many C++ string implementations use the {{Small String Optimization}} to speed
up work with small strings. For example: {code}Microsoft STL, libstdc++,
libc++, Boost, Folly.{code}
was:
Implement Small String Optimization for StringValue.
Current memory layout of StringValue is:
{noformat}
char* ptr; // 8 byte
int len; // 4 byte
{noformat}
For small strings with size up to 8 we could store the string contents in the
bytes of the 'ptr'. Something like that:
{noformat}
union {
char* ptr;
char small_buf[sizeof(ptr)];
}
int len;
{noformat}
Many C++ string implementations use the {{Small String Optimization}} to speed
up work with small strings. For example: {{{}Microsoft STL{}}},
{{{}libstdc++{+}{+}{}}}, {{{}libc++{}}}, {{{}Boost{}}}, {{{}Folly{}}}.
> Implement Small String Optimization for StringValue
> ---------------------------------------------------
>
> Key: IMPALA-12373
> URL: https://issues.apache.org/jira/browse/IMPALA-12373
> Project: IMPALA
> Issue Type: Improvement
> Reporter: Zoltán Borók-Nagy
> Priority: Major
>
> Implement Small String Optimization for StringValue.
> Current memory layout of StringValue is:
> {noformat}
> char* ptr; // 8 byte
> int len; // 4 byte
> {noformat}
> For small strings with size up to 8 we could store the string contents in the
> bytes of the 'ptr'. Something like that:
> {noformat}
> union {
> char* ptr;
> char small_buf[sizeof(ptr)];
> }
> int len;
> {noformat}
> Many C++ string implementations use the {{Small String Optimization}} to
> speed up work with small strings. For example: {code}Microsoft STL,
> libstdc++, libc++, Boost, Folly.{code}
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