diff --git a/src/storage/compression/fsst.cpp b/src/storage/compression/fsst.cpp
index bad017835047..b3ad41cca960 100644
--- a/src/storage/compression/fsst.cpp
+++ b/src/storage/compression/fsst.cpp
@@ -12,6 +12,39 @@
 #include "fsst.h"
 #include "miniz_wrapper.hpp"
 
+/*
+Data layout per segment:
++------------------------------------------------+
+|                  Header                        |
+|   +----------------------------------------+   |
+|   |   fsst_compression_header_t  header    |   |
+|   +----------------------------------------+   |
+|                                                |
++------------------------------------------------+
+|               Index Buffer                 |
+|   +------------------------------------+   |
+|   |   uint16_t index_buffer_idx[]      |   |
+|   +------------------------------------+   |
+|      tuple index -> index buffer idx       |
+|                (bitpacked)                 |
+|                                            |
++--------------------------------------------+
+|               Symbol Table                 |
+|   +------------------------------------+   |
+|   |   duckdb_fsst_decoder_t  table     |   |
+|   +------------------------------------+   |
+|  symbol table used to compress the strings |
+|                                            |
++--------------------------------------------+
+|                Dictionary                  |
+|   +------------------------------------+   |
+|   |   uint8_t *raw_string_data         |   |
+|   +------------------------------------+   |
+|      the string data without lengths       |
+|                                            |
++--------------------------------------------+
+*/
+
 namespace duckdb {
 struct FSSTScanState;
 
@@ -79,12 +112,10 @@ struct FSSTAnalyzeState : public AnalyzeState {
 	}
 
 	~FSSTAnalyzeState() override {
-		if (fsst_encoder) {
-			duckdb_fsst_destroy(fsst_encoder);
-		}
+		duckdb_fsst_destroy(fsst_encoder.get());
 	}
 
-	duckdb_fsst_encoder_t *fsst_encoder = nullptr;
+	optional_ptr<duckdb_fsst_encoder_t> fsst_encoder;
 	idx_t count;
 
 	StringHeap fsst_string_heap;
@@ -172,10 +203,10 @@ idx_t FSSTStorage::StringFinalAnalyze(AnalyzeState &state_p) {
 	// TODO: do we really need to encode to get a size estimate?
 	auto compressed_ptrs = vector<unsigned char *>(string_count, nullptr);
 	auto compressed_sizes = vector<size_t>(string_count, 0);
-	unique_ptr<unsigned char[]> compressed_buffer(new unsigned char[output_buffer_size]);
+	auto compressed_buffer = make_unsafe_uniq_array<uint8_t>(output_buffer_size);
 
 	auto res =
-	    duckdb_fsst_compress(state.fsst_encoder, string_count, &fsst_string_sizes[0], &fsst_string_ptrs[0],
+	    duckdb_fsst_compress(state.fsst_encoder.get(), string_count, &fsst_string_sizes[0], &fsst_string_ptrs[0],
 	                         output_buffer_size, compressed_buffer.get(), &compressed_sizes[0], &compressed_ptrs[0]);
 
 	if (string_count != res) {
@@ -215,9 +246,7 @@ class FSSTCompressionState : public CompressionState {
 	}
 
 	~FSSTCompressionState() override {
-		if (fsst_encoder) {
-			duckdb_fsst_destroy(fsst_encoder);
-		}
+		duckdb_fsst_destroy(fsst_encoder.get());
 	}
 
 	void Reset() {
@@ -354,11 +383,7 @@ class FSSTCompressionState : public CompressionState {
 		                                               current_segment->count, current_width);
 
 		// Write the fsst symbol table or nothing
-		if (fsst_encoder != nullptr) {
-			memcpy(base_ptr + symbol_table_offset, &fsst_serialized_symbol_table[0], fsst_serialized_symbol_table_size);
-		} else {
-			memset(base_ptr + symbol_table_offset, 0, fsst_serialized_symbol_table_size);
-		}
+		memcpy(base_ptr + symbol_table_offset, &fsst_serialized_symbol_table[0], fsst_serialized_symbol_table_size);
 
 		Store<uint32_t>(NumericCast<uint32_t>(symbol_table_offset),
 		                data_ptr_cast(&header_ptr->fsst_symbol_table_offset));
@@ -399,7 +424,7 @@ class FSSTCompressionState : public CompressionState {
 	bitpacking_width_t current_width;
 	idx_t last_fitting_size;
 
-	duckdb_fsst_encoder_t *fsst_encoder = nullptr;
+	optional_ptr<duckdb_fsst_encoder_t> fsst_encoder;
 	unsigned char fsst_serialized_symbol_table[sizeof(duckdb_fsst_decoder_t)];
 	size_t fsst_serialized_symbol_table_size = sizeof(duckdb_fsst_decoder_t);
 };
@@ -413,9 +438,10 @@ unique_ptr<CompressionState> FSSTStorage::InitCompression(ColumnDataCheckpointer
 		throw InternalException("No encoder found during FSST compression");
 	}
 
-	compression_state->fsst_encoder = analyze_state.fsst_encoder;
+	compression_state->fsst_encoder = std::move(analyze_state.fsst_encoder);
 	compression_state->fsst_serialized_symbol_table_size =
-	    duckdb_fsst_export(compression_state->fsst_encoder, &compression_state->fsst_serialized_symbol_table[0]);
+	    duckdb_fsst_export(compression_state->fsst_encoder.get(), &compression_state->fsst_serialized_symbol_table[0]);
+	// FIXME: move of 'optional_ptr' should already set to null, no???
 	analyze_state.fsst_encoder = nullptr;
 
 	return std::move(compression_state);
@@ -470,14 +496,14 @@ void FSSTStorage::Compress(CompressionState &state_p, Vector &scan_vector, idx_t
 	vector<unsigned char> compress_buffer(compress_buffer_size, 0);
 
 	auto res = duckdb_fsst_compress(
-	    state.fsst_encoder,   /* IN: encoder obtained from duckdb_fsst_create(). */
-	    total_count,          /* IN: number of strings in batch to compress. */
-	    &sizes_in[0],         /* IN: byte-lengths of the inputs */
-	    &strings_in[0],       /* IN: input string start pointers. */
-	    compress_buffer_size, /* IN: byte-length of output buffer. */
-	    &compress_buffer[0],  /* OUT: memory buffer to put the compressed strings in (one after the other). */
-	    &sizes_out[0],        /* OUT: byte-lengths of the compressed strings. */
-	    &strings_out[0]       /* OUT: output string start pointers. Will all point into [output,output+size). */
+	    state.fsst_encoder.get(), /* IN: encoder obtained from duckdb_fsst_create(). */
+	    total_count,              /* IN: number of strings in batch to compress. */
+	    sizes_in.data(),          /* IN: byte-lengths of the inputs */
+	    strings_in.data(),        /* IN: input string start pointers. */
+	    compress_buffer_size,     /* IN: byte-length of output buffer. */
+	    compress_buffer.data(),   /* OUT: memory buffer to put the compressed strings in (one after the other). */
+	    sizes_out.data(),         /* OUT: byte-lengths of the compressed strings. */
+	    strings_out.data()        /* OUT: output string start pointers. Will all point into [output,output+size). */
 	);
 
 	if (res != total_count) {