88 * Portions Copyright (c) 1994, Regents of the University of California
99 *
1010 * IDENTIFICATION
11- * $Header: /cvsroot/pgsql/src/backend/storage/freespace/freespace.c,v 1.23 2003/09 /2900:05:25 petere Exp $
11+ * $Header: /cvsroot/pgsql/src/backend/storage/freespace/freespace.c,v 1.24 2003/10 /2917:36:57 tgl Exp $
1212 *
1313 *
1414 * NOTES:
@@ -1432,19 +1432,29 @@ compact_fsm_storage(void)
14321432
14331433/*
14341434 * It's possible that we have to move data down, not up, if the
1435- * allocations of previous rels expanded. Thisshould mean that
1435+ * allocations of previous rels expanded. Thisnormally means that
14361436 * our allocation expanded too (or at least got no worse), and
1437- * ditto for later rels. So there should be room --- but we might
1438- * have to push down following rels to make it. We don't want to
1439- * do the push more than once, so pack everything against the end
1440- * of the arena if so.
1437+ * ditto for later rels. So there should be room to move all our
1438+ * data down without dropping any --- but we might have to push down
1439+ * following rels to acquire the room. We don't want to do the push
1440+ * more than once, so pack everything against the end of the arena
1441+ * if so.
1442+ *
1443+ * In corner cases where roundoff has affected our allocation, it's
1444+ * possible that we have to move down and compress our data too.
1445+ * Since this case is extremely infrequent, we do not try to be smart
1446+ * about it --- we just drop pages from the end of the rel's data.
14411447 */
14421448if (newChunkIndex > oldChunkIndex )
14431449{
14441450int limitChunkIndex ;
14451451
14461452if (newAllocPages < fsmrel -> storedPages )
1447- elog (PANIC ,"can't juggle and compress too" );
1453+ {
1454+ /* move and compress --- just drop excess pages */
1455+ fsmrel -> storedPages = newAllocPages ;
1456+ curChunks = fsm_current_chunks (fsmrel );
1457+ }
14481458if (fsmrel -> nextPhysical != NULL )
14491459limitChunkIndex = fsmrel -> nextPhysical -> firstChunk ;
14501460else
@@ -1459,7 +1469,7 @@ compact_fsm_storage(void)
14591469else
14601470limitChunkIndex = FreeSpaceMap -> totalChunks ;
14611471if (newChunkIndex + curChunks > limitChunkIndex )
1462- elog (PANIC ,"insufficient room" );
1472+ elog (PANIC ,"insufficient room in FSM " );
14631473}
14641474memmove (newLocation ,oldLocation ,curChunks * CHUNKBYTES );
14651475}
@@ -1535,7 +1545,7 @@ push_fsm_rels_after(FSMRelation *afterRel)
15351545if (newChunkIndex < oldChunkIndex )
15361546{
15371547/* trouble... */
1538- elog (PANIC ,"out of room" );
1548+ elog (PANIC ,"insufficient room in FSM " );
15391549}
15401550else if (newChunkIndex > oldChunkIndex )
15411551{