branches/zip: Minor improvements.

buf_flush_init_for_writing(): Calculate the checksum with the actual zip_size.

buf_calc_zblob_page_checksum(): Skip the field FIL_PAGE_SPACE_OR_CHKSUM.

trx_sys_doublewrite_init_or_restore_page(): Use the actual zip_size.

page_cur_insert_rec_low(): If page_zip_alloc() fails, try compressing the
whole page afterwards.

buf/buf0buf.c

@@ -244,8 +244,8 @@ buf_calc_zblob_page_checksum(
 	const byte*	page,		/* in: compressed BLOB page */
 	ulint		zip_size)	/* in: size of the page, in bytes */
 {
-	return(ut_fold_binary(page + FIL_PAGE_SPACE_OR_CHKSUM,
-			zip_size - FIL_PAGE_SPACE_OR_CHKSUM) & 0xFFFFFFFFUL);
+	return(ut_fold_binary(page + FIL_PAGE_OFFSET,
+			zip_size - FIL_PAGE_OFFSET) & 0xFFFFFFFFUL);
 }
 
 /************************************************************************

buf/buf0flu.c

@@ -454,8 +454,9 @@ buf_flush_init_for_writing(
 	ulint	page_no)	/* in: page number */
 {
 	page_zip_des_t*	page_zip = page_zip_;
+	ulint		zip_size = fil_space_get_zip_size(space);
 
-	if (fil_space_get_zip_size(space)) {
+	if (zip_size) {
 		switch (fil_page_get_type(page)) {
 		case FIL_PAGE_TYPE_ZBLOB:
 			ut_ad(!page_zip);
@@ -465,7 +466,7 @@ buf_flush_init_for_writing(
 			mach_write_to_4(page + FIL_PAGE_SPACE_OR_CHKSUM,
 					srv_use_checksums
 					? buf_calc_zblob_page_checksum(
-							page, 16384/* TODO */)
+							page, zip_size)
 					: BUF_NO_CHECKSUM_MAGIC);
 			return;
 		case FIL_PAGE_INDEX:

page/page0cur.c

@@ -905,6 +905,7 @@ page_cur_insert_rec_low(
 	ulint		heap_no;	/* heap number of the inserted record */
 	rec_t*		current_rec;	/* current record after which the
 					new record is inserted */
+	page_zip_des_t*	page_zip_orig	= page_zip;
 
 	ut_ad(cursor && mtr);
 	ut_ad(rec_offs_validate(rec, index, offsets));
@@ -923,7 +924,8 @@ page_cur_insert_rec_low(
 	if (UNIV_LIKELY_NULL(page_zip)
 	    && !page_zip_alloc(page_zip, page, index, rec_size, 1, mtr)) {
 
-		return(NULL);
+		/* Try compressing the whole page afterwards. */
+		page_zip = NULL;
 	}
 
 	insert_buf = page_header_get_ptr(page, PAGE_FREE);
@@ -1107,6 +1109,15 @@ page_cur_insert_rec_low(
 		page_zip_dir_rewrite(page_zip, page);
 
 		page_zip_write_rec(page_zip, insert_rec, index, offsets, 1);
+	} else if (UNIV_LIKELY_NULL(page_zip_orig)) {
+		/* Recompress the page. */
+		if (!page_zip_compress(page_zip_orig, page, index)) {
+			/* Out of space: restore the page */
+			if (!page_zip_decompress(page_zip_orig, page)) {
+				ut_error; /* Memory corrupted? */
+			}
+			return(NULL);
+		}
 	}
 
 	/* 9. Write log record of the insert */

trx/trx0sys.c

@@ -472,9 +472,8 @@ trx_sys_doublewrite_init_or_restore_pages(
 					UNIV_PAGE_SIZE, read_buf, NULL);
 			/* Check if the page is corrupt */
 
-			if (space_id && fil_page_get_type(read_buf)
-					== FIL_PAGE_TYPE_ZBLOB) {
-				zip_size = 16384; /* TODO */
+			if (space_id) {
+				zip_size = fil_space_get_zip_size(space_id);
 			} else {
 				zip_size = 0;
 			}