Fixed XA recovery for InnoDB. Note that XA recovery is still disabled

until it has been comprehensive tested.


innobase/log/log0log.c:
  Added general documentation of InnoDB redo-logs.
innobase/trx/trx0roll.c:
  Prepared transactions are not rolled back in a recovery if
  innobase_force_recovery = 0. But they are rolled back if
  innobase_force_recovery > 0.
innobase/trx/trx0trx.c:
  Disable the XA code in InnoDB crash recovery until it has been
  comprehensive tested. SHOW INNODB STATUS now prints different
  output for prepared transactions.
innobase/trx/trx0undo.c:
  Do not unnecessary write X/Open XA XID. XID is written in the prepare.
  Space for a XID should be reserved at this stage.
sql/ha_innodb.cc:
  Remove error.

innobase/log/log0log.c

@@ -24,6 +24,32 @@ Created 12/9/1995 Heikki Tuuri
 #include "trx0sys.h"
 #include "trx0trx.h"
 
+/*
+General philosophy of InnoDB redo-logs:
+
+1) Every change to a contents of a data page must be done
+through mtr, which in mtr_commit() writes log records
+to the InnoDB redo log.
+
+2) Normally these changes are performed using a mlog_write_ulint()
+or similar function.
+
+3) In some page level operations only a code number of a 
+c-function and its parameters are written to the log to 
+reduce the size of the log.
+
+  3a) You should not add parameters to these kind of functions
+  (e.g. trx_undo_header_create(), trx_undo_insert_header_reuse())
+
+  3b) You should not add such functionality which either change
+  working when compared with the old or are dependent on data
+  outside of the page. These kind of functions should implement
+  self-contained page transformation and it should be unchanged
+  if you don't have very essential reasons to change log
+  semantics or format.
+
+*/
+
 /* Current free limit of space 0; protected by the log sys mutex; 0 means
 uninitialized */
 ulint	log_fsp_current_free_limit		= 0;

innobase/trx/trx0roll.c

@@ -440,7 +440,17 @@ trx_rollback_or_clean_all_without_sess(
 		if ((trx->sess || (trx->conc_state == TRX_NOT_STARTED))) {
 			trx = UT_LIST_GET_NEXT(trx_list, trx);
 		} else if (trx->conc_state == TRX_PREPARED) {
+
+			/* Roll back all prepared transactions if
+			innobase_force_recovery > 0 in my.cnf */
+
+			if (srv_force_recovery > 0) {
+				trx->conc_state = TRX_ACTIVE;
+				break;
+			} else {
 				trx->sess = trx_dummy_sess;
+				trx = UT_LIST_GET_NEXT(trx_list, trx);
+			}
 		} else {
 			break;
 		}

innobase/trx/trx0trx.c

@@ -440,9 +440,9 @@ trx_lists_init_at_db_start(void)
 					ut_dulint_get_high(trx->id),
 					ut_dulint_get_low(trx->id));
 
-				/*	trx->conc_state = TRX_PREPARED; */
-				 	trx->conc_state =
-						TRX_ACTIVE;
+					trx->conc_state = TRX_ACTIVE;
+
+					/* trx->conc_state = TRX_PREPARED;*/
 				} else {
 					trx->conc_state =
 						TRX_COMMITTED_IN_MEMORY;
@@ -498,16 +498,15 @@ trx_lists_init_at_db_start(void)
 					commit or abort decision from MySQL */
 
 					if (undo->state == TRX_UNDO_PREPARED) {
-
  						fprintf(stderr,
 "InnoDB: Transaction %lu %lu was in the XA prepared state.\n",
 						ut_dulint_get_high(trx->id),
 						ut_dulint_get_low(trx->id));
 
-					/* trx->conc_state = TRX_PREPARED; */
-					trx->conc_state =
-						TRX_ACTIVE;
+						trx->conc_state = TRX_ACTIVE;
 
+						/* trx->conc_state = 
+							TRX_PREPARED; */
 					} else {
 						trx->conc_state =
 						  TRX_COMMITTED_IN_MEMORY;
@@ -1638,10 +1637,13 @@ trx_print(
 			fputs(", not started", f);
 			break;
 		case TRX_ACTIVE:
-		case TRX_PREPARED:
 			fprintf(f, ", ACTIVE %lu sec",
 				(ulong)difftime(time(NULL), trx->start_time));
                         break;
+		case TRX_PREPARED:
+			fprintf(f, ", ACTIVE (PREPARED) %lu sec",
+				(ulong)difftime(time(NULL), trx->start_time));
+                        break;
 		case TRX_COMMITTED_IN_MEMORY:
 			fputs(", COMMITTED IN MEMORY", f);
 			break;
@@ -1938,7 +1940,7 @@ trx_get_trx_by_xid(
 
 		if (xid->gtrid_length == trx->xid.gtrid_length &&
 		    xid->bqual_length == trx->xid.bqual_length &&
-		    memcmp(xid, &trx->xid, 
+		    memcmp(xid->data, trx->xid.data, 
 				xid->gtrid_length + 
 				xid->bqual_length) == 0) {
 			break;

innobase/trx/trx0undo.c

@@ -599,11 +599,10 @@ trx_undo_read_xid(
 Adds the XA XID after an undo log old-style header. */
 static
 void
-trx_undo_header_add_xid(
-/*====================*/
+trx_undo_header_add_space_for_xid(
+/*==============================*/
 	page_t*		undo_page,/* in: undo log segment header page */
 	trx_ulogf_t*	log_hdr,/* in: undo log header */
-	XID*		xid,	/* in: X/Open XA transaction identification */
 	mtr_t*		mtr)	/* in: mtr */
 {
 	trx_upagef_t*	page_hdr;
@@ -620,9 +619,8 @@ trx_undo_header_add_xid(
 
 	new_free = free + (TRX_UNDO_LOG_XA_HDR_SIZE
 						- TRX_UNDO_LOG_OLD_HDR_SIZE);
-	trx_undo_write_xid(log_hdr, xid, mtr);
 
-	/* Now that we added the XID after the header, update the free offset
+	/* Add space for a XID after the header, update the free offset
 	fields on the undo log page and in the undo log header */
 
 	mlog_write_ulint(page_hdr + TRX_UNDO_PAGE_START, new_free,
@@ -1532,7 +1530,7 @@ trx_undo_create(
 	
 	offset = trx_undo_header_create(undo_page, trx_id, mtr);
 
-	trx_undo_header_add_xid(undo_page, undo_page + offset, xid, mtr);
+	trx_undo_header_add_space_for_xid(undo_page, undo_page + offset, mtr);
 
 	undo = trx_undo_mem_create(rseg, id, type, trx_id, xid,
 							page_no, offset);
@@ -1599,7 +1597,7 @@ trx_undo_reuse_cached(
 
 	if (type == TRX_UNDO_INSERT) {
 		offset = trx_undo_insert_header_reuse(undo_page, trx_id, mtr);
-		trx_undo_header_add_xid(undo_page, undo_page + offset, xid,
+		trx_undo_header_add_space_for_xid(undo_page, undo_page + offset,
 									mtr);
 	} else {
 		ut_a(mach_read_from_2(undo_page + TRX_UNDO_PAGE_HDR
@@ -1607,7 +1605,7 @@ trx_undo_reuse_cached(
 						== TRX_UNDO_UPDATE);
 
 		offset = trx_undo_header_create(undo_page, trx_id, mtr);
-		trx_undo_header_add_xid(undo_page, undo_page + offset, xid,
+		trx_undo_header_add_space_for_xid(undo_page, undo_page + offset,
 									mtr);
 	}
 	

sql/ha_innodb.cc

@@ -3071,9 +3071,6 @@ ha_innobase::unlock_row(void)
 
 	DBUG_ENTER("ha_innobase::unlock_row");
 
-	ut_ad(prebuilt->trx ==
-		(trx_t*) current_thd->transaction.all.innobase_tid);
-
 	if (last_query_id != user_thd->query_id) {
 		ut_print_timestamp(stderr);
 		fprintf(stderr,