branches/zip:

Fix the way how btr_free_externally_stored_field() is called in purge.

btr_free_externally_stored_field(): Add parameter field_ref that points
directly to the BLOB reference.  Use rec, offsets, page_zip, and i
only for the page_zip_write_blob_ptr() call.

row_purge_upd_exist_or_extern(): Do not assume that the undo log contains
the entire record.  Only pass the BLOB reference to
btr_free_externally_stored_field().

btr/btr0cur.c

@@ -3779,12 +3779,15 @@ btr_free_externally_stored_field(
 					from purge where 'data' is located on
 					an undo log page, not an index
 					page) */
-	rec_t*		rec,		/* in/out: record */
-	const ulint*	offsets,	/* in: rec_get_offsets(rec, index) */
-	page_zip_des_t*	page_zip,	/* in: compressed page whose
-					uncompressed part will be updated,
+	byte*		field_ref,	/* in/out: field reference */
+	rec_t*		rec,		/* in: record containing field_ref, for
+					page_zip_write_blob_ptr(), or NULL */
+	const ulint*	offsets,	/* in: rec_get_offsets(rec, index),
 					or NULL */
-	ulint		i,		/* in: field number */
+	page_zip_des_t*	page_zip,	/* in: compressed page corresponding
+					to rec, or NULL if rec == NULL */
+	ulint		i,		/* in: field number of field_ref;
+					ignored if rec == NULL */
 	ibool		do_not_free_inherited,/* in: TRUE if called in a
 					rollback and we do not want to free
 					inherited fields */
@@ -3794,7 +3797,6 @@ btr_free_externally_stored_field(
 {
 	page_t*	page;
 	page_t*	rec_page;
-	byte*	field_ref;
 	ulint	space_id;
 	ulint	page_no;
 	ulint	next_page_no;
@@ -3802,17 +3804,20 @@ btr_free_externally_stored_field(
 
 	ut_ad(mtr_memo_contains(local_mtr, dict_tree_get_lock(index->tree),
 							MTR_MEMO_X_LOCK));
-	ut_ad(mtr_memo_contains(local_mtr, buf_block_align(rec),
+	ut_ad(mtr_memo_contains(local_mtr, buf_block_align(field_ref),
 							MTR_MEMO_PAGE_X_FIX));
-	ut_ad(rec_offs_validate(rec, index, offsets));
+	ut_ad(!rec || rec_offs_validate(rec, index, offsets));
 
-	{
+#ifdef UNIV_DEBUG
+	if (rec) {
 		ulint	local_len;
-		field_ref = rec_get_nth_field(rec, offsets, i, &local_len);
+		byte*	f = rec_get_nth_field(rec, offsets, i, &local_len);
 		ut_a(local_len >= BTR_EXTERN_FIELD_REF_SIZE);
 		local_len -= BTR_EXTERN_FIELD_REF_SIZE;
-		field_ref += local_len;
+		f += local_len;
+		ut_ad(f == field_ref);
 	}
+#endif /* UNIV_DEBUG */
 	
 	for (;;) {
 		mtr_start(&mtr);
@@ -3858,11 +3863,10 @@ btr_free_externally_stored_field(
 			mlog_write_ulint(field_ref + BTR_EXTERN_LEN + 4,
 						0,
 						MLOG_4BYTES, &mtr);
-#if ZIP_BLOB
-			if (page_zip)
-#endif
-			page_zip_write_blob_ptr(page_zip, rec, index, offsets,
-								i, &mtr);
+			if (UNIV_LIKELY_NULL(page_zip)) {
+				page_zip_write_blob_ptr(page_zip,
+						rec, index, offsets, i, &mtr);
+			}
 		} else {
 			ulint	extern_len	= mach_read_from_4(
 					field_ref + BTR_EXTERN_LEN + 4);
@@ -3935,9 +3939,14 @@ btr_rec_free_externally_stored_fields(
 
 	for (i = 0; i < n_fields; i++) {
 		if (rec_offs_nth_extern(offsets, i)) {
+			ulint	len;
+			byte*	data = rec_get_nth_field(
+					rec, offsets, i, &len);
+			ut_a(len >= BTR_EXTERN_FIELD_REF_SIZE);
 
-			btr_free_externally_stored_field(index, rec, offsets,
-						page_zip, i,
+			btr_free_externally_stored_field(index,
+					data + len - BTR_EXTERN_FIELD_REF_SIZE,
+					rec, offsets, page_zip, i,
 					do_not_free_inherited, mtr);
 		}
 	}
@@ -3979,9 +3988,15 @@ btr_rec_free_updated_extern_fields(
 		ufield = upd_get_nth_field(update, i);
 	
 		if (rec_offs_nth_extern(offsets, ufield->field_no)) {
-
-			btr_free_externally_stored_field(index, rec, offsets,
-						page_zip, ufield->field_no,
+			ulint	len;
+			byte*	data = rec_get_nth_field(
+					rec, offsets, ufield->field_no, &len);
+			ut_a(len >= BTR_EXTERN_FIELD_REF_SIZE);
+
+			btr_free_externally_stored_field(index,
+					data + len - BTR_EXTERN_FIELD_REF_SIZE,
+					rec, offsets, page_zip,
+					ufield->field_no,
 					do_not_free_inherited, mtr);
 		}
 	}

include/btr0cur.h

@@ -481,12 +481,15 @@ btr_free_externally_stored_field(
 					from purge where 'data' is located on
 					an undo log page, not an index
 					page) */
-	rec_t*		rec,		/* in/out: record */
-	const ulint*	offsets,	/* in: rec_get_offsets(rec, index) */
-	page_zip_des_t*	page_zip,	/* in: compressed page whose
-					uncompressed part will be updated,
+	byte*		field_ref,	/* in/out: field reference */
+	rec_t*		rec,		/* in: record containing field_ref, for
+					page_zip_write_blob_ptr(), or NULL */
+	const ulint*	offsets,	/* in: rec_get_offsets(rec, index),
 					or NULL */
-	ulint		i,		/* in: field number */
+	page_zip_des_t*	page_zip,	/* in: compressed page corresponding
+					to rec, or NULL if rec == NULL */
+	ulint		i,		/* in: field number of field_ref;
+					ignored if rec == NULL */
 	ibool		do_not_free_inherited,/* in: TRUE if called in a
 					rollback and we do not want to free
 					inherited fields */

row/row0purge.c

@@ -371,15 +371,12 @@ row_purge_upd_exist_or_extern(
 	ulint		page_no;
 	ulint		offset;
 	ulint		i;
-	ulint*		offsets;
 	mtr_t		mtr;
 	
 	ut_ad(node);
-	offsets = NULL;
 
 	if (node->rec_type == TRX_UNDO_UPD_DEL_REC) {
 
-		heap = NULL;
 		goto skip_secondaries;
 	}
 
@@ -399,7 +396,7 @@ row_purge_upd_exist_or_extern(
 		node->index = dict_table_get_next_index(node->index);
 	}
 
-	mem_heap_empty(heap);	
+	mem_heap_free(heap);	
 
 skip_secondaries:
 	/* Free possible externally stored fields */
@@ -408,9 +405,8 @@ skip_secondaries:
 		ufield = upd_get_nth_field(node->update, i);
 
 		if (UNIV_UNLIKELY(ufield->extern_storage)) {
-			byte*	rec;
-			ulint	j;
 			ulint	internal_offset;
+			byte*	data_field;
 
 			/* We use the fact that new_val points to
 			node->undo_rec and get thus the offset of
@@ -449,44 +445,22 @@ skip_secondaries:
 			/* We assume in purge of externally stored fields
 			that the space id of the undo log record is 0! */
 
-			rec = buf_page_get(0, page_no, RW_X_LATCH, &mtr)
-				     + offset;
+			data_field = buf_page_get(0, page_no, RW_X_LATCH, &mtr)
+				     + offset + internal_offset;
 
 #ifdef UNIV_SYNC_DEBUG
-			buf_page_dbg_add_level(buf_frame_align(rec),
+			buf_page_dbg_add_level(buf_frame_align(data_field),
 						SYNC_TRX_UNDO_PAGE);
 #endif /* UNIV_SYNC_DEBUG */
-
-			offsets = rec_get_offsets(rec, index, offsets,
-						ULINT_UNDEFINED, &heap);
-			for (j = 0; j < rec_offs_n_fields(offsets); j++) {
-				ulint	len;
-				byte*	field = rec_get_nth_field(
-						rec, offsets, j, &len);
-
-				if (UNIV_UNLIKELY(rec + internal_offset
-						== field)) {
-					ut_a(len == ufield->new_val.len);
-					ut_a(rec_offs_nth_extern(offsets, j));
-					goto found_field;
-				}
-			}
-
-			/* field not found */
-			ut_error;
-			
-found_field:
-			btr_free_externally_stored_field(index, rec, offsets,
-					buf_block_get_page_zip(
-					buf_block_align(rec)),
-					j, FALSE, &mtr);
+			ut_a(ufield->new_val.len >= BTR_EXTERN_FIELD_REF_SIZE);
+			btr_free_externally_stored_field(index, data_field
+						+ ufield->new_val.len
+						- BTR_EXTERN_FIELD_REF_SIZE,
+						NULL, NULL, NULL, 0,
+						FALSE, &mtr);
 			mtr_commit(&mtr);
 		}
 	}
-
-	if (heap) {
-		mem_heap_free(heap);
-	}
 }
 
 /***************************************************************