Attempt to speedup dictionaries with memory alignment

alexey-milovidov · alexey-milovidov · commit 856ed0fc3129 · 2025-08-16T06:07:59.000+02:00
diff --git a/src/Columns/ColumnArray.cpp b/src/Columns/ColumnArray.cpp
@@ -227,7 +227,7 @@ StringRef ColumnArray::serializeValueIntoArena(size_t n, Arena & arena, char con
     size_t array_size = sizeAt(n);
     size_t offset = offsetAt(n);
 
-    char * pos = arena.allocContinue(sizeof(array_size), begin);
+    char * pos = arena.allocContinue(sizeof(array_size), begin, sizeof(array_size));
     memcpy(pos, &array_size, sizeof(array_size));
 
     StringRef res(pos, sizeof(array_size));
diff --git a/src/Columns/ColumnString.cpp b/src/Columns/ColumnString.cpp
@@ -263,7 +263,7 @@ StringRef ColumnString::serializeValueIntoArena(size_t n, Arena & arena, char co
 
     StringRef res;
     res.size = sizeof(string_size) + string_size;
-    char * pos = arena.allocContinue(res.size, begin);
+    char * pos = arena.allocContinue(res.size, begin, sizeof(string_size));
     memcpy(pos, &string_size, sizeof(string_size));
     memcpy(pos + sizeof(string_size), &chars[offset], string_size);
     res.data = pos;
diff --git a/src/Columns/ColumnVariant.cpp b/src/Columns/ColumnVariant.cpp
@@ -790,7 +790,7 @@ StringRef ColumnVariant::serializeValueIntoArena(size_t n, Arena & arena, char c
 {
     /// During any serialization/deserialization we should always use global discriminators.
     Discriminator global_discr = globalDiscriminatorAt(n);
-    char * pos = arena.allocContinue(sizeof(global_discr), begin);
+    char * pos = arena.allocContinue(sizeof(global_discr), begin, sizeof(global_discr));
     memcpy(pos, &global_discr, sizeof(global_discr));
     StringRef res(pos, sizeof(global_discr));
 

Original file line number	Diff line number	Diff line change
`@@ -790,7 +790,7 @@ StringRef ColumnVariant::serializeValueIntoArena(size_t n, Arena & arena, char c`
`790`	`790`	`{`
`791`	`791`	`/// During any serialization/deserialization we should always use global discriminators.`
`792`	`792`	`Discriminator global_discr = globalDiscriminatorAt(n);`
`793`		`- char * pos = arena.allocContinue(sizeof(global_discr), begin);`
	`793`	`+ char * pos = arena.allocContinue(sizeof(global_discr), begin, sizeof(global_discr));`
`794`	`794`	`memcpy(pos, &global_discr, sizeof(global_discr));`
`795`	`795`	`StringRef res(pos, sizeof(global_discr));`
`796`	`796`