[GitHub] [arrow] cyb70289 commented on a change in pull request #12504: ARROW-15763: [C++] Improve CSV writer

[GitBox <gi...@apache.org>]

cyb70289 commented on a change in pull request #12504:
URL: https://github.com/apache/arrow/pull/12504#discussion_r813500124



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File path: cpp/src/arrow/csv/writer.cc
##########
@@ -170,11 +178,17 @@ class UnquotedColumnPopulator : public ColumnPopulator {
       RETURN_NOT_OK(CheckStringArrayHasNoStructuralChars(*casted_array_, delimiter_));
     }
 
-    for (int x = 0; x < casted_array_->length(); x++) {
-      row_lengths[x] += casted_array_->IsNull(x)
-                            ? static_cast<int32_t>(null_string_->size())
-                            : casted_array_->value_length(x);
-    }

Review comment:
       `VisistArrayDataInline` processes continuous non-null / null blocks in batch and performs better than this bit by bit checking, though looks doing more work (extracts the string_view but only string length is needed).




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