diff options
Diffstat (limited to 'src/backend/storage/smgr/md.c')
| -rw-r--r-- | src/backend/storage/smgr/md.c | 25 |
1 files changed, 21 insertions, 4 deletions
diff --git a/src/backend/storage/smgr/md.c b/src/backend/storage/smgr/md.c index 3c1c81a7295..167d61c1afe 100644 --- a/src/backend/storage/smgr/md.c +++ b/src/backend/storage/smgr/md.c @@ -115,7 +115,7 @@ typedef struct _MdfdVec struct _MdfdVec *mdfd_chain; /* next segment, or NULL */ } MdfdVec; -static MemoryContext MdCxt; /* context for all md.c allocations */ +static MemoryContext MdCxt; /* context for all MdfdVec objects */ /* @@ -157,6 +157,7 @@ typedef struct static HTAB *pendingOpsTable = NULL; static List *pendingUnlinks = NIL; +static MemoryContext pendingOpsCxt; /* context for the above */ static CycleCtr mdsync_cycle_ctr = 0; static CycleCtr mdckpt_cycle_ctr = 0; @@ -209,11 +210,27 @@ mdinit(void) { HASHCTL hash_ctl; + /* + * XXX: The checkpointer needs to add entries to the pending ops table + * when absorbing fsync requests. That is done within a critical + * section, which isn't usually allowed, but we make an exception. + * It means that there's a theoretical possibility that you run out of + * memory while absorbing fsync requests, which leads to a PANIC. + * Fortunately the hash table is small so that's unlikely to happen in + * practice. + */ + pendingOpsCxt = AllocSetContextCreate(MdCxt, + "Pending Ops Context", + ALLOCSET_DEFAULT_MINSIZE, + ALLOCSET_DEFAULT_INITSIZE, + ALLOCSET_DEFAULT_MAXSIZE); + MemoryContextAllowInCriticalSection(pendingOpsCxt, true); + MemSet(&hash_ctl, 0, sizeof(hash_ctl)); hash_ctl.keysize = sizeof(RelFileNode); hash_ctl.entrysize = sizeof(PendingOperationEntry); hash_ctl.hash = tag_hash; - hash_ctl.hcxt = MdCxt; + hash_ctl.hcxt = pendingOpsCxt; pendingOpsTable = hash_create("Pending Ops Table", 100L, &hash_ctl, @@ -1516,7 +1533,7 @@ RememberFsyncRequest(RelFileNode rnode, ForkNumber forknum, BlockNumber segno) else if (segno == UNLINK_RELATION_REQUEST) { /* Unlink request: put it in the linked list */ - MemoryContext oldcxt = MemoryContextSwitchTo(MdCxt); + MemoryContext oldcxt = MemoryContextSwitchTo(pendingOpsCxt); PendingUnlinkEntry *entry; /* PendingUnlinkEntry doesn't store forknum, since it's always MAIN */ @@ -1533,7 +1550,7 @@ RememberFsyncRequest(RelFileNode rnode, ForkNumber forknum, BlockNumber segno) else { /* Normal case: enter a request to fsync this segment */ - MemoryContext oldcxt = MemoryContextSwitchTo(MdCxt); + MemoryContext oldcxt = MemoryContextSwitchTo(pendingOpsCxt); PendingOperationEntry *entry; bool found; |