[SPARK-23762][SQL] UTF8StringBuffer uses MemoryBlock

[kiszk]

What changes were proposed in this pull request?

This PR tries to use MemoryBlock in UTF8StringBuffer. In general, there are two advantages to use MemoryBlock.

1. Has clean API calls rather than using a Java array or PlatformMemory
2. Improve runtime performance of memory access instead of using Object.

How was this patch tested?

Added UTF8StringBufferSuite

[SparkQA]

Test build #88462 has finished for PR 20871 at commit d6aaef7.

• This patch fails RAT tests.
• This patch merges cleanly.
• This patch adds no public classes.

[SparkQA]

Test build #88469 has finished for PR 20871 at commit 7db100f.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[SparkQA]

Test build #88894 has finished for PR 20871 at commit 0d0f271.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[kiszk]

retest this please

[SparkQA]

Test build #88964 has finished for PR 20871 at commit ba81497.

• This patch fails Spark unit tests.
• This patch merges cleanly.
• This patch adds no public classes.

[kiszk]

retest this please

[viirya]

Since totalSize is privately used only, and now it is simply length, I think we can remove it and just use length.

[SparkQA]

Test build #88963 has finished for PR 20871 at commit ba81497.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[SparkQA]

Test build #88967 has finished for PR 20871 at commit ba81497.

• This patch fails due to an unknown error code, -9.
• This patch merges cleanly.
• This patch adds no public classes.

[viirya]

UTF8StringBufferSuite -> UTF8StringBuilderSuite?

[kiszk]

Good catch

[SparkQA]

Test build #88972 has finished for PR 20871 at commit 1d75cf3.

• This patch fails Spark unit tests.
• This patch merges cleanly.
• This patch adds no public classes.

[SparkQA]

Test build #88988 has finished for PR 20871 at commit a7665fd.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds the following public classes (experimental):
• class UTF8StringBuilderSuite extends SparkFunSuite

[kiszk]

ping @cloud-fan

[viirya]

LGTM

[viirya]

Btw, it is better to check if any lint-java issue because this involves java change.

[kiszk]

Thank you for your suggestion. I installed checkstyle plug-in into Intellij today.

[kiszk]

ping @cloud-fan

[kiszk]

retest this please

[SparkQA]

Test build #89148 has finished for PR 20871 at commit a7665fd.

• This patch fails Spark unit tests.
• This patch merges cleanly.
• This patch adds the following public classes (experimental):
• class UTF8StringBuilderSuite extends SparkFunSuite

[kiszk]

retest this please

[SparkQA]

Test build #89171 has finished for PR 20871 at commit a7665fd.

• This patch fails due to an unknown error code, -9.
• This patch merges cleanly.
• This patch adds the following public classes (experimental):
• class UTF8StringBuilderSuite extends SparkFunSuite

[kiszk]

retest this please

[SparkQA]

Test build #89191 has finished for PR 20871 at commit a7665fd.

• This patch fails Spark unit tests.
• This patch merges cleanly.
• This patch adds the following public classes (experimental):
• class UTF8StringBuilderSuite extends SparkFunSuite

[kiszk]

retest this please

[SparkQA]

Test build #89196 has finished for PR 20871 at commit a7665fd.

• This patch fails Spark unit tests.
• This patch merges cleanly.
• This patch adds the following public classes (experimental):
• class UTF8StringBuilderSuite extends SparkFunSuite

[kiszk]

retest this please

[SparkQA]

Test build #89211 has finished for PR 20871 at commit a7665fd.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds the following public classes (experimental):
• class UTF8StringBuilderSuite extends SparkFunSuite

[kiszk]

ping @cloud-fan

[cloud-fan]

thanks, merging to master!