Don't pass DetoastIterator to toast_decompress_iterate()

Author: Nikita Glukhov

src/backend/access/common/toast_compression.c

@@ -249,7 +249,9 @@ lz4_decompress_datum_slice(const struct varlena *value, int32 slicelength)
 
 void
 toast_decompress_iterate(ToastBuffer *source, ToastBuffer *dest,
-						 DetoastIterator iter, const char *destend)
+						 ToastCompressionId compression_method,
+						 void **decompression_state,
+						 const char *destend)
 {
 	const char *sp;
 	const char *srcend;
@@ -278,13 +280,13 @@ toast_decompress_iterate(ToastBuffer *source, ToastBuffer *dest,
 	/*
 	 * Decompress the data using the appropriate decompression routine.
 	 */
-	switch (iter->compression_method)
+	switch (compression_method)
 	{
 		case TOAST_PGLZ_COMPRESSION_ID:
 			dlen = pglz_decompress_state(sp, &slen, dp, destend - dp,
 										 last_source_chunk && destend == dest->capacity,
 										 last_source_chunk,
-										 &iter->decompression_state);
+										 decompression_state);
 			break;
 		case TOAST_LZ4_COMPRESSION_ID:
 			if (source->limit < source->capacity)
@@ -310,7 +312,7 @@ toast_decompress_iterate(ToastBuffer *source, ToastBuffer *dest,
 			}
 			break;
 		default:
-			elog(ERROR, "invalid compression method id %d", iter->compression_method);
+			elog(ERROR, "invalid compression method id %d", compression_method);
 			return;		/* keep compiler quiet */
 	}
 

src/include/access/detoast.h

@@ -112,7 +112,9 @@ extern void fetch_datum_iterate(FetchDatumIterator iter);
 extern ToastBuffer *create_toast_buffer(int32 size, bool compressed);
 extern void free_toast_buffer(ToastBuffer *buf);
 extern void toast_decompress_iterate(ToastBuffer *source, ToastBuffer *dest,
-									 DetoastIterator iter, const char *destend);
+									 ToastCompressionId compression_method,
+									 void **decompression_state,
+									 const char *destend);
 extern void pglz_decompress_iterate(ToastBuffer *source, ToastBuffer *dest,
 									DetoastIterator iter, char *destend);
 
@@ -166,7 +168,10 @@ detoast_iterate(DetoastIterator detoast_iter, const char *destend)
 		fetch_datum_iterate(fetch_iter);
 
 	if (detoast_iter->compressed)
-		toast_decompress_iterate(fetch_iter->buf, detoast_iter->buf, detoast_iter, destend);
+		toast_decompress_iterate(fetch_iter->buf, detoast_iter->buf,
+								 detoast_iter->compression_method,
+								 &detoast_iter->decompression_state,
+								 destend);
 
 	if (detoast_iter->buf->limit == detoast_iter->buf->capacity)
 		detoast_iter->done = true;