BiteTheDDDDt commented on code in PR #10169:
URL: https://github.com/apache/doris/pull/10169#discussion_r904476530


##########
be/src/vec/functions/like.cpp:
##########
@@ -129,6 +130,42 @@ Status FunctionLikeBase::vector_vector(const 
ColumnString::Chars& values,
                                        const ColumnString::Offsets& 
pattern_offsets,
                                        ColumnUInt8::Container& result, const 
LikeFn& function,
                                        LikeSearchState* search_state) {
+    // for constant_substring_fn, use long run length search for performance
+    if (constant_substring_fn ==
+        *(function.target<doris::Status (*)(LikeSearchState * state, const 
StringValue&,
+                                            const StringValue&, unsigned 
char*)>())) {
+        // treat continous multi string data as a long string data
+        const UInt8* begin = values.data();
+        const UInt8* end = begin + values.size();
+        const UInt8* pos = begin;
+
+        /// Current index in the array of strings.
+        size_t i = 0;
+        size_t needle_size = 
search_state->substring_pattern.get_pattern_length();
+
+        /// We will search for the next occurrence in all strings at once.
+        while (pos < end) {
+            // search return matched substring start offset
+            pos = (UInt8*)search_state->substring_pattern.search((char*)pos, 
end - pos);
+            if (pos >= end) break;
+
+            /// Determine which index it refers to.
+            /// begin + value_offsets[i] is the start offset of string at i+1
+            while (begin + value_offsets[i] <= pos) ++i;
+
+            /// We check that the entry does not pass through the boundaries 
of strings.

Review Comment:
   `values.data` will be "abcd\0efgh" here.
   But after my investigation, there may be `\0` in the input string, this 
check is necessary.



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