* md.c
* This code manages relations that reside on magnetic disk.
*
- * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
+ * Or at least, that was what the Berkeley folk had in mind when they named
+ * this file. In reality, what this code provides is an interface from
+ * the smgr API to Unix-like filesystem APIs, so it will work with any type
+ * of device for which the operating system provides filesystem support.
+ * It doesn't matter whether the bits are on spinning rust or some other
+ * storage technology.
+ *
+ * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/storage/smgr/md.c,v 1.127 2007/01/17 16:25:01 tgl Exp $
+ * src/backend/storage/smgr/md.c
*
*-------------------------------------------------------------------------
*/
#include <fcntl.h>
#include <sys/file.h>
-#include "catalog/catalog.h"
#include "miscadmin.h"
+#include "access/xlogutils.h"
+#include "access/xlog.h"
+#include "pgstat.h"
+#include "portability/instr_time.h"
#include "postmaster/bgwriter.h"
#include "storage/fd.h"
#include "storage/bufmgr.h"
+#include "storage/relfilenode.h"
#include "storage/smgr.h"
#include "utils/hsearch.h"
#include "utils/memutils.h"
+#include "pg_trace.h"
-/* interval for calling AbsorbFsyncRequests in mdsync */
+/* intervals for calling AbsorbFsyncRequests in mdsync and mdpostckpt */
#define FSYNCS_PER_ABSORB 10
+#define UNLINKS_PER_ABSORB 10
-/* special values for the segno arg to RememberFsyncRequest */
+/*
+ * Special values for the segno arg to RememberFsyncRequest.
+ *
+ * Note that CompactCheckpointerRequestQueue assumes that it's OK to remove an
+ * fsync request from the queue if an identical, subsequent request is found.
+ * See comments there before making changes here.
+ */
#define FORGET_RELATION_FSYNC (InvalidBlockNumber)
#define FORGET_DATABASE_FSYNC (InvalidBlockNumber-1)
+#define UNLINK_RELATION_REQUEST (InvalidBlockNumber-2)
/*
* On Windows, we have to interpret EACCES as possibly meaning the same as
* ENOENT, because if a file is unlinked-but-not-yet-gone on that platform,
* that's what you get. Ugh. This code is designed so that we don't
* actually believe these cases are okay without further evidence (namely,
- * a pending fsync request getting revoked ... see mdsync).
+ * a pending fsync request getting canceled ... see mdsync).
*/
#ifndef WIN32
-#define FILE_POSSIBLY_DELETED(err) ((err) == ENOENT)
+#define FILE_POSSIBLY_DELETED(err) ((err) == ENOENT)
#else
-#define FILE_POSSIBLY_DELETED(err) ((err) == ENOENT || (err) == EACCES)
+#define FILE_POSSIBLY_DELETED(err) ((err) == ENOENT || (err) == EACCES)
#endif
/*
* system's file size limit (often 2GBytes). In order to do that,
* we break relations up into "segment" files that are each shorter than
* the OS file size limit. The segment size is set by the RELSEG_SIZE
- * configuration constant in pg_config_manual.h.
+ * configuration constant in pg_config.h.
*
* On disk, a relation must consist of consecutively numbered segment
* files in the pattern
* Inactive segments are those that once contained data but are currently
* not needed because of an mdtruncate() operation. The reason for leaving
* them present at size zero, rather than unlinking them, is that other
- * backends and/or the bgwriter might be holding open file references to
+ * backends and/or the checkpointer might be holding open file references to
* such segments. If the relation expands again after mdtruncate(), such
* that a deactivated segment becomes active again, it is important that
* such file references still be valid --- else data might get written
* out to an unlinked old copy of a segment file that will eventually
* disappear.
*
- * The file descriptor pointer (md_fd field) stored in the SMgrRelation
- * cache is, therefore, just the head of a list of MdfdVec objects, one
- * per segment. But note the md_fd pointer can be NULL, indicating
- * relation not open.
- *
- * Also note that mdfd_chain == NULL does not necessarily mean the relation
- * doesn't have another segment after this one; we may just not have
- * opened the next segment yet. (We could not have "all segments are
- * in the chain" as an invariant anyway, since another backend could
- * extend the relation when we weren't looking.) We do not make chain
+ * File descriptors are stored in the per-fork md_seg_fds arrays inside
+ * SMgrRelation. The length of these arrays is stored in md_num_open_segs.
+ * Note that a fork's md_num_open_segs having a specific value does not
+ * necessarily mean the relation doesn't have additional segments; we may
+ * just not have opened the next segment yet. (We could not have "all
+ * segments are in the array" as an invariant anyway, since another backend
+ * could extend the relation while we aren't looking.) We do not have
* entries for inactive segments, however; as soon as we find a partial
* segment, we assume that any subsequent segments are inactive.
*
- * All MdfdVec objects are palloc'd in the MdCxt memory context.
- *
- * Defining LET_OS_MANAGE_FILESIZE disables the segmentation logic,
- * for use on machines that support large files. Beware that that
- * code has not been tested in a long time and is probably bit-rotted.
+ * The entire MdfdVec array is palloc'd in the MdCxt memory context.
*/
typedef struct _MdfdVec
{
File mdfd_vfd; /* fd number in fd.c's pool */
BlockNumber mdfd_segno; /* segment number, from 0 */
-#ifndef LET_OS_MANAGE_FILESIZE /* for large relations */
- struct _MdfdVec *mdfd_chain; /* next segment, or NULL */
-#endif
} MdfdVec;
-static MemoryContext MdCxt; /* context for all md.c allocations */
+static MemoryContext MdCxt; /* context for all MdfdVec objects */
/*
- * In some contexts (currently, standalone backends and the bgwriter process)
+ * In some contexts (currently, standalone backends and the checkpointer)
* we keep track of pending fsync operations: we need to remember all relation
* segments that have been written since the last checkpoint, so that we can
* fsync them down to disk before completing the next checkpoint. This hash
- * table remembers the pending operations. We use a hash table mostly as
- * a convenient way of eliminating duplicate requests.
+ * table remembers the pending operations. We use a hash table mostly as
+ * a convenient way of merging duplicate requests.
+ *
+ * We use a similar mechanism to remember no-longer-needed files that can
+ * be deleted after the next checkpoint, but we use a linked list instead of
+ * a hash table, because we don't expect there to be any duplicate requests.
+ *
+ * These mechanisms are only used for non-temp relations; we never fsync
+ * temp rels, nor do we need to postpone their deletion (see comments in
+ * mdunlink).
*
* (Regular backends do not track pending operations locally, but forward
- * them to the bgwriter.)
+ * them to the checkpointer.)
*/
+typedef uint16 CycleCtr; /* can be any convenient integer size */
+
typedef struct
{
- RelFileNode rnode; /* the targeted relation */
- BlockNumber segno; /* which segment */
-} PendingOperationTag;
+ RelFileNode rnode; /* hash table key (must be first!) */
+ CycleCtr cycle_ctr; /* mdsync_cycle_ctr of oldest request */
+ /* requests[f] has bit n set if we need to fsync segment n of fork f */
+ Bitmapset *requests[MAX_FORKNUM + 1];
+ /* canceled[f] is true if we canceled fsyncs for fork "recently" */
+ bool canceled[MAX_FORKNUM + 1];
+} PendingOperationEntry;
typedef struct
{
- PendingOperationTag tag; /* hash table key (must be first!) */
- int failures; /* number of failed attempts to fsync */
-} PendingOperationEntry;
+ RelFileNode rnode; /* the dead relation to delete */
+ CycleCtr cycle_ctr; /* mdckpt_cycle_ctr when request was made */
+} PendingUnlinkEntry;
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;
+
+
+/*** behavior for mdopen & _mdfd_getseg ***/
+/* ereport if segment not present */
+#define EXTENSION_FAIL (1 << 0)
+/* return NULL if segment not present */
+#define EXTENSION_RETURN_NULL (1 << 1)
+/* create new segments as needed */
+#define EXTENSION_CREATE (1 << 2)
+/* create new segments if needed during recovery */
+#define EXTENSION_CREATE_RECOVERY (1 << 3)
+/*
+ * Allow opening segments which are preceded by segments smaller than
+ * RELSEG_SIZE, e.g. inactive segments (see above). Note that this is breaks
+ * mdnblocks() and related functionality henceforth - which currently is ok,
+ * because this is only required in the checkpointer which never uses
+ * mdnblocks().
+ */
+#define EXTENSION_DONT_CHECK_SIZE (1 << 4)
-typedef enum /* behavior for mdopen & _mdfd_getseg */
-{
- EXTENSION_FAIL, /* ereport if segment not present */
- EXTENSION_RETURN_NULL, /* return NULL if not present */
- EXTENSION_CREATE /* create new segments as needed */
-} ExtensionBehavior;
-
/* local routines */
-static MdfdVec *mdopen(SMgrRelation reln, ExtensionBehavior behavior);
-static void register_dirty_segment(SMgrRelation reln, MdfdVec *seg);
-static MdfdVec *_fdvec_alloc(void);
-
-#ifndef LET_OS_MANAGE_FILESIZE
-static MdfdVec *_mdfd_openseg(SMgrRelation reln, BlockNumber segno,
- int oflags);
-#endif
-static MdfdVec *_mdfd_getseg(SMgrRelation reln, BlockNumber blkno,
- bool isTemp, ExtensionBehavior behavior);
-static BlockNumber _mdnblocks(SMgrRelation reln, MdfdVec *seg);
+static void mdunlinkfork(RelFileNodeBackend rnode, ForkNumber forkNum,
+ bool isRedo);
+static MdfdVec *mdopen(SMgrRelation reln, ForkNumber forknum, int behavior);
+static void register_dirty_segment(SMgrRelation reln, ForkNumber forknum,
+ MdfdVec *seg);
+static void register_unlink(RelFileNodeBackend rnode);
+static void _fdvec_resize(SMgrRelation reln,
+ ForkNumber forknum,
+ int nseg);
+static char *_mdfd_segpath(SMgrRelation reln, ForkNumber forknum,
+ BlockNumber segno);
+static MdfdVec *_mdfd_openseg(SMgrRelation reln, ForkNumber forkno,
+ BlockNumber segno, int oflags);
+static MdfdVec *_mdfd_getseg(SMgrRelation reln, ForkNumber forkno,
+ BlockNumber blkno, bool skipFsync, int behavior);
+static BlockNumber _mdnblocks(SMgrRelation reln, ForkNumber forknum,
+ MdfdVec *seg);
/*
{
MdCxt = AllocSetContextCreate(TopMemoryContext,
"MdSmgr",
- ALLOCSET_DEFAULT_MINSIZE,
- ALLOCSET_DEFAULT_INITSIZE,
- ALLOCSET_DEFAULT_MAXSIZE);
+ ALLOCSET_DEFAULT_SIZES);
/*
* Create pending-operations hashtable if we need it. Currently, we need
- * it if we are standalone (not under a postmaster) OR if we are a
- * bootstrap-mode subprocess of a postmaster (that is, a startup or
- * bgwriter process).
+ * it if we are standalone (not under a postmaster) or if we are a startup
+ * or checkpointer auxiliary process.
*/
- if (!IsUnderPostmaster || IsBootstrapProcessingMode())
+ if (!IsUnderPostmaster || AmStartupProcess() || AmCheckpointerProcess())
{
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_SIZES);
+ MemoryContextAllowInCriticalSection(pendingOpsCxt, true);
+
MemSet(&hash_ctl, 0, sizeof(hash_ctl));
- hash_ctl.keysize = sizeof(PendingOperationTag);
+ 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,
- HASH_ELEM | HASH_FUNCTION | HASH_CONTEXT);
+ HASH_ELEM | HASH_BLOBS | HASH_CONTEXT);
+ pendingUnlinks = NIL;
}
}
+/*
+ * In archive recovery, we rely on checkpointer to do fsyncs, but we will have
+ * already created the pendingOpsTable during initialization of the startup
+ * process. Calling this function drops the local pendingOpsTable so that
+ * subsequent requests will be forwarded to checkpointer.
+ */
+void
+SetForwardFsyncRequests(void)
+{
+ /* Perform any pending fsyncs we may have queued up, then drop table */
+ if (pendingOpsTable)
+ {
+ mdsync();
+ hash_destroy(pendingOpsTable);
+ }
+ pendingOpsTable = NULL;
+
+ /*
+ * We should not have any pending unlink requests, since mdunlink doesn't
+ * queue unlink requests when isRedo.
+ */
+ Assert(pendingUnlinks == NIL);
+}
+
+/*
+ * mdexists() -- Does the physical file exist?
+ *
+ * Note: this will return true for lingering files, with pending deletions
+ */
+bool
+mdexists(SMgrRelation reln, ForkNumber forkNum)
+{
+ /*
+ * Close it first, to ensure that we notice if the fork has been unlinked
+ * since we opened it.
+ */
+ mdclose(reln, forkNum);
+
+ return (mdopen(reln, forkNum, EXTENSION_RETURN_NULL) != NULL);
+}
+
/*
* mdcreate() -- Create a new relation on magnetic disk.
*
* If isRedo is true, it's okay for the relation to exist already.
*/
void
-mdcreate(SMgrRelation reln, bool isRedo)
+mdcreate(SMgrRelation reln, ForkNumber forkNum, bool isRedo)
{
+ MdfdVec *mdfd;
char *path;
File fd;
- if (isRedo && reln->md_fd != NULL)
+ if (isRedo && reln->md_num_open_segs[forkNum] > 0)
return; /* created and opened already... */
- Assert(reln->md_fd == NULL);
+ Assert(reln->md_num_open_segs[forkNum] == 0);
- path = relpath(reln->smgr_rnode);
+ path = relpath(reln->smgr_rnode, forkNum);
- fd = PathNameOpenFile(path, O_RDWR | O_CREAT | O_EXCL | PG_BINARY, 0600);
+ fd = PathNameOpenFile(path, O_RDWR | O_CREAT | O_EXCL | PG_BINARY);
if (fd < 0)
{
* During bootstrap, there are cases where a system relation will be
* accessed (by internal backend processes) before the bootstrap
* script nominally creates it. Therefore, allow the file to exist
- * already, even if isRedo is not set. (See also mdopen)
+ * already, even if isRedo is not set. (See also mdopen)
*/
if (isRedo || IsBootstrapProcessingMode())
- fd = PathNameOpenFile(path, O_RDWR | PG_BINARY, 0600);
+ fd = PathNameOpenFile(path, O_RDWR | PG_BINARY);
if (fd < 0)
{
- pfree(path);
/* be sure to report the error reported by create, not open */
errno = save_errno;
ereport(ERROR,
(errcode_for_file_access(),
- errmsg("could not create relation %u/%u/%u: %m",
- reln->smgr_rnode.spcNode,
- reln->smgr_rnode.dbNode,
- reln->smgr_rnode.relNode)));
+ errmsg("could not create file \"%s\": %m", path)));
}
}
pfree(path);
- reln->md_fd = _fdvec_alloc();
-
- reln->md_fd->mdfd_vfd = fd;
- reln->md_fd->mdfd_segno = 0;
-#ifndef LET_OS_MANAGE_FILESIZE
- reln->md_fd->mdfd_chain = NULL;
-#endif
+ _fdvec_resize(reln, forkNum, 1);
+ mdfd = &reln->md_seg_fds[forkNum][0];
+ mdfd->mdfd_vfd = fd;
+ mdfd->mdfd_segno = 0;
}
/*
* mdunlink() -- Unlink a relation.
*
- * Note that we're passed a RelFileNode --- by the time this is called,
+ * Note that we're passed a RelFileNodeBackend --- by the time this is called,
* there won't be an SMgrRelation hashtable entry anymore.
*
- * If isRedo is true, it's okay for the relation to be already gone.
- * Also, any failure should be reported as WARNING not ERROR, because
+ * forkNum can be a fork number to delete a specific fork, or InvalidForkNumber
+ * to delete all forks.
+ *
+ * For regular relations, we don't unlink the first segment file of the rel,
+ * but just truncate it to zero length, and record a request to unlink it after
+ * the next checkpoint. Additional segments can be unlinked immediately,
+ * however. Leaving the empty file in place prevents that relfilenode
+ * number from being reused. The scenario this protects us from is:
+ * 1. We delete a relation (and commit, and actually remove its file).
+ * 2. We create a new relation, which by chance gets the same relfilenode as
+ * the just-deleted one (OIDs must've wrapped around for that to happen).
+ * 3. We crash before another checkpoint occurs.
+ * During replay, we would delete the file and then recreate it, which is fine
+ * if the contents of the file were repopulated by subsequent WAL entries.
+ * But if we didn't WAL-log insertions, but instead relied on fsyncing the
+ * file after populating it (as for instance CLUSTER and CREATE INDEX do),
+ * the contents of the file would be lost forever. By leaving the empty file
+ * until after the next checkpoint, we prevent reassignment of the relfilenode
+ * number until it's safe, because relfilenode assignment skips over any
+ * existing file.
+ *
+ * We do not need to go through this dance for temp relations, though, because
+ * we never make WAL entries for temp rels, and so a temp rel poses no threat
+ * to the health of a regular rel that has taken over its relfilenode number.
+ * The fact that temp rels and regular rels have different file naming
+ * patterns provides additional safety.
+ *
+ * All the above applies only to the relation's main fork; other forks can
+ * just be removed immediately, since they are not needed to prevent the
+ * relfilenode number from being recycled. Also, we do not carefully
+ * track whether other forks have been created or not, but just attempt to
+ * unlink them unconditionally; so we should never complain about ENOENT.
+ *
+ * If isRedo is true, it's unsurprising for the relation to be already gone.
+ * Also, we should remove the file immediately instead of queuing a request
+ * for later, since during redo there's no possibility of creating a
+ * conflicting relation.
+ *
+ * Note: any failure should be reported as WARNING not ERROR, because
* we are usually not in a transaction anymore when this is called.
*/
void
-mdunlink(RelFileNode rnode, bool isRedo)
+mdunlink(RelFileNodeBackend rnode, ForkNumber forkNum, bool isRedo)
+{
+ /*
+ * We have to clean out any pending fsync requests for the doomed
+ * relation, else the next mdsync() will fail. There can't be any such
+ * requests for a temp relation, though. We can send just one request
+ * even when deleting multiple forks, since the fsync queuing code accepts
+ * the "InvalidForkNumber = all forks" convention.
+ */
+ if (!RelFileNodeBackendIsTemp(rnode))
+ ForgetRelationFsyncRequests(rnode.node, forkNum);
+
+ /* Now do the per-fork work */
+ if (forkNum == InvalidForkNumber)
+ {
+ for (forkNum = 0; forkNum <= MAX_FORKNUM; forkNum++)
+ mdunlinkfork(rnode, forkNum, isRedo);
+ }
+ else
+ mdunlinkfork(rnode, forkNum, isRedo);
+}
+
+static void
+mdunlinkfork(RelFileNodeBackend rnode, ForkNumber forkNum, bool isRedo)
{
char *path;
+ int ret;
+
+ path = relpath(rnode, forkNum);
/*
- * We have to clean out any pending fsync requests for the doomed relation,
- * else the next mdsync() will fail.
+ * Delete or truncate the first segment.
*/
- ForgetRelationFsyncRequests(rnode);
+ if (isRedo || forkNum != MAIN_FORKNUM || RelFileNodeBackendIsTemp(rnode))
+ {
+ ret = unlink(path);
+ if (ret < 0 && errno != ENOENT)
+ ereport(WARNING,
+ (errcode_for_file_access(),
+ errmsg("could not remove file \"%s\": %m", path)));
+ }
+ else
+ {
+ /* truncate(2) would be easier here, but Windows hasn't got it */
+ int fd;
- path = relpath(rnode);
+ fd = OpenTransientFile(path, O_RDWR | PG_BINARY);
+ if (fd >= 0)
+ {
+ int save_errno;
- /* Delete the first segment, or only segment if not doing segmenting */
- if (unlink(path) < 0)
- {
- if (!isRedo || errno != ENOENT)
+ ret = ftruncate(fd, 0);
+ save_errno = errno;
+ CloseTransientFile(fd);
+ errno = save_errno;
+ }
+ else
+ ret = -1;
+ if (ret < 0 && errno != ENOENT)
ereport(WARNING,
(errcode_for_file_access(),
- errmsg("could not remove relation %u/%u/%u: %m",
- rnode.spcNode,
- rnode.dbNode,
- rnode.relNode)));
+ errmsg("could not truncate file \"%s\": %m", path)));
+
+ /* Register request to unlink first segment later */
+ register_unlink(rnode);
}
-#ifndef LET_OS_MANAGE_FILESIZE
- /* Delete the additional segments, if any */
- else
+ /*
+ * Delete any additional segments.
+ */
+ if (ret >= 0)
{
char *segpath = (char *) palloc(strlen(path) + 12);
BlockNumber segno;
/*
- * Note that because we loop until getting ENOENT, we will
- * correctly remove all inactive segments as well as active ones.
+ * Note that because we loop until getting ENOENT, we will correctly
+ * remove all inactive segments as well as active ones.
*/
for (segno = 1;; segno++)
{
if (errno != ENOENT)
ereport(WARNING,
(errcode_for_file_access(),
- errmsg("could not remove segment %u of relation %u/%u/%u: %m",
- segno,
- rnode.spcNode,
- rnode.dbNode,
- rnode.relNode)));
+ errmsg("could not remove file \"%s\": %m", segpath)));
break;
}
}
pfree(segpath);
}
-#endif
pfree(path);
}
* causes intervening file space to become filled with zeroes.
*/
void
-mdextend(SMgrRelation reln, BlockNumber blocknum, char *buffer, bool isTemp)
+mdextend(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
+ char *buffer, bool skipFsync)
{
- long seekpos;
+ off_t seekpos;
int nbytes;
MdfdVec *v;
/* This assert is too expensive to have on normally ... */
#ifdef CHECK_WRITE_VS_EXTEND
- Assert(blocknum >= mdnblocks(reln));
+ Assert(blocknum >= mdnblocks(reln, forknum));
#endif
/*
- * If a relation manages to grow to 2^32-1 blocks, refuse to extend it
- * any more --- we mustn't create a block whose number
- * actually is InvalidBlockNumber.
+ * If a relation manages to grow to 2^32-1 blocks, refuse to extend it any
+ * more --- we mustn't create a block whose number actually is
+ * InvalidBlockNumber.
*/
if (blocknum == InvalidBlockNumber)
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
- errmsg("cannot extend relation %u/%u/%u beyond %u blocks",
- reln->smgr_rnode.spcNode,
- reln->smgr_rnode.dbNode,
- reln->smgr_rnode.relNode,
+ errmsg("cannot extend file \"%s\" beyond %u blocks",
+ relpath(reln->smgr_rnode, forknum),
InvalidBlockNumber)));
- v = _mdfd_getseg(reln, blocknum, isTemp, EXTENSION_CREATE);
+ v = _mdfd_getseg(reln, forknum, blocknum, skipFsync, EXTENSION_CREATE);
-#ifndef LET_OS_MANAGE_FILESIZE
- seekpos = (long) (BLCKSZ * (blocknum % ((BlockNumber) RELSEG_SIZE)));
- Assert(seekpos < BLCKSZ * RELSEG_SIZE);
-#else
- seekpos = (long) (BLCKSZ * (blocknum));
-#endif
+ seekpos = (off_t) BLCKSZ * (blocknum % ((BlockNumber) RELSEG_SIZE));
- /*
- * Note: because caller usually obtained blocknum by calling mdnblocks,
- * which did a seek(SEEK_END), this seek is often redundant and will be
- * optimized away by fd.c. It's not redundant, however, if there is a
- * partial page at the end of the file. In that case we want to try to
- * overwrite the partial page with a full page. It's also not redundant
- * if bufmgr.c had to dump another buffer of the same file to make room
- * for the new page's buffer.
- */
- if (FileSeek(v->mdfd_vfd, seekpos, SEEK_SET) != seekpos)
- ereport(ERROR,
- (errcode_for_file_access(),
- errmsg("could not seek to block %u of relation %u/%u/%u: %m",
- blocknum,
- reln->smgr_rnode.spcNode,
- reln->smgr_rnode.dbNode,
- reln->smgr_rnode.relNode)));
+ Assert(seekpos < (off_t) BLCKSZ * RELSEG_SIZE);
- if ((nbytes = FileWrite(v->mdfd_vfd, buffer, BLCKSZ)) != BLCKSZ)
+ if ((nbytes = FileWrite(v->mdfd_vfd, buffer, BLCKSZ, seekpos, WAIT_EVENT_DATA_FILE_EXTEND)) != BLCKSZ)
{
if (nbytes < 0)
ereport(ERROR,
(errcode_for_file_access(),
- errmsg("could not extend relation %u/%u/%u: %m",
- reln->smgr_rnode.spcNode,
- reln->smgr_rnode.dbNode,
- reln->smgr_rnode.relNode),
+ errmsg("could not extend file \"%s\": %m",
+ FilePathName(v->mdfd_vfd)),
errhint("Check free disk space.")));
/* short write: complain appropriately */
ereport(ERROR,
(errcode(ERRCODE_DISK_FULL),
- errmsg("could not extend relation %u/%u/%u: wrote only %d of %d bytes at block %u",
- reln->smgr_rnode.spcNode,
- reln->smgr_rnode.dbNode,
- reln->smgr_rnode.relNode,
+ errmsg("could not extend file \"%s\": wrote only %d of %d bytes at block %u",
+ FilePathName(v->mdfd_vfd),
nbytes, BLCKSZ, blocknum),
errhint("Check free disk space.")));
}
- if (!isTemp)
- register_dirty_segment(reln, v);
+ if (!skipFsync && !SmgrIsTemp(reln))
+ register_dirty_segment(reln, forknum, v);
-#ifndef LET_OS_MANAGE_FILESIZE
- Assert(_mdnblocks(reln, v) <= ((BlockNumber) RELSEG_SIZE));
-#endif
+ Assert(_mdnblocks(reln, forknum, v) <= ((BlockNumber) RELSEG_SIZE));
}
/*
* invent one out of whole cloth.
*/
static MdfdVec *
-mdopen(SMgrRelation reln, ExtensionBehavior behavior)
+mdopen(SMgrRelation reln, ForkNumber forknum, int behavior)
{
MdfdVec *mdfd;
char *path;
File fd;
/* No work if already open */
- if (reln->md_fd)
- return reln->md_fd;
+ if (reln->md_num_open_segs[forknum] > 0)
+ return &reln->md_seg_fds[forknum][0];
- path = relpath(reln->smgr_rnode);
+ path = relpath(reln->smgr_rnode, forknum);
- fd = PathNameOpenFile(path, O_RDWR | PG_BINARY, 0600);
+ fd = PathNameOpenFile(path, O_RDWR | PG_BINARY);
if (fd < 0)
{
* substitute for mdcreate() in bootstrap mode only. (See mdcreate)
*/
if (IsBootstrapProcessingMode())
- fd = PathNameOpenFile(path, O_RDWR | O_CREAT | O_EXCL | PG_BINARY, 0600);
+ fd = PathNameOpenFile(path, O_RDWR | O_CREAT | O_EXCL | PG_BINARY);
if (fd < 0)
{
- pfree(path);
- if (behavior == EXTENSION_RETURN_NULL &&
+ if ((behavior & EXTENSION_RETURN_NULL) &&
FILE_POSSIBLY_DELETED(errno))
+ {
+ pfree(path);
return NULL;
+ }
ereport(ERROR,
(errcode_for_file_access(),
- errmsg("could not open relation %u/%u/%u: %m",
- reln->smgr_rnode.spcNode,
- reln->smgr_rnode.dbNode,
- reln->smgr_rnode.relNode)));
+ errmsg("could not open file \"%s\": %m", path)));
}
}
pfree(path);
- reln->md_fd = mdfd = _fdvec_alloc();
-
+ _fdvec_resize(reln, forknum, 1);
+ mdfd = &reln->md_seg_fds[forknum][0];
mdfd->mdfd_vfd = fd;
mdfd->mdfd_segno = 0;
-#ifndef LET_OS_MANAGE_FILESIZE
- mdfd->mdfd_chain = NULL;
- Assert(_mdnblocks(reln, mdfd) <= ((BlockNumber) RELSEG_SIZE));
-#endif
+
+ Assert(_mdnblocks(reln, forknum, mdfd) <= ((BlockNumber) RELSEG_SIZE));
return mdfd;
}
* mdclose() -- Close the specified relation, if it isn't closed already.
*/
void
-mdclose(SMgrRelation reln)
+mdclose(SMgrRelation reln, ForkNumber forknum)
{
- MdfdVec *v = reln->md_fd;
+ int nopensegs = reln->md_num_open_segs[forknum];
/* No work if already closed */
- if (v == NULL)
+ if (nopensegs == 0)
return;
- reln->md_fd = NULL; /* prevent dangling pointer after error */
-
-#ifndef LET_OS_MANAGE_FILESIZE
- while (v != NULL)
+ /* close segments starting from the end */
+ while (nopensegs > 0)
{
- MdfdVec *ov = v;
+ MdfdVec *v = &reln->md_seg_fds[forknum][nopensegs - 1];
/* if not closed already */
if (v->mdfd_vfd >= 0)
+ {
FileClose(v->mdfd_vfd);
- /* Now free vector */
- v = v->mdfd_chain;
- pfree(ov);
+ v->mdfd_vfd = -1;
+ }
+
+ nopensegs--;
+ }
+
+ /* resize just once, avoids pointless reallocations */
+ _fdvec_resize(reln, forknum, 0);
+}
+
+/*
+ * mdprefetch() -- Initiate asynchronous read of the specified block of a relation
+ */
+void
+mdprefetch(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum)
+{
+#ifdef USE_PREFETCH
+ off_t seekpos;
+ MdfdVec *v;
+
+ v = _mdfd_getseg(reln, forknum, blocknum, false, EXTENSION_FAIL);
+
+ seekpos = (off_t) BLCKSZ * (blocknum % ((BlockNumber) RELSEG_SIZE));
+
+ Assert(seekpos < (off_t) BLCKSZ * RELSEG_SIZE);
+
+ (void) FilePrefetch(v->mdfd_vfd, seekpos, BLCKSZ, WAIT_EVENT_DATA_FILE_PREFETCH);
+#endif /* USE_PREFETCH */
+}
+
+/*
+ * mdwriteback() -- Tell the kernel to write pages back to storage.
+ *
+ * This accepts a range of blocks because flushing several pages at once is
+ * considerably more efficient than doing so individually.
+ */
+void
+mdwriteback(SMgrRelation reln, ForkNumber forknum,
+ BlockNumber blocknum, BlockNumber nblocks)
+{
+ /*
+ * Issue flush requests in as few requests as possible; have to split at
+ * segment boundaries though, since those are actually separate files.
+ */
+ while (nblocks > 0)
+ {
+ BlockNumber nflush = nblocks;
+ off_t seekpos;
+ MdfdVec *v;
+ int segnum_start,
+ segnum_end;
+
+ v = _mdfd_getseg(reln, forknum, blocknum, true /* not used */ ,
+ EXTENSION_RETURN_NULL);
+
+ /*
+ * We might be flushing buffers of already removed relations, that's
+ * ok, just ignore that case.
+ */
+ if (!v)
+ return;
+
+ /* compute offset inside the current segment */
+ segnum_start = blocknum / RELSEG_SIZE;
+
+ /* compute number of desired writes within the current segment */
+ segnum_end = (blocknum + nblocks - 1) / RELSEG_SIZE;
+ if (segnum_start != segnum_end)
+ nflush = RELSEG_SIZE - (blocknum % ((BlockNumber) RELSEG_SIZE));
+
+ Assert(nflush >= 1);
+ Assert(nflush <= nblocks);
+
+ seekpos = (off_t) BLCKSZ * (blocknum % ((BlockNumber) RELSEG_SIZE));
+
+ FileWriteback(v->mdfd_vfd, seekpos, (off_t) BLCKSZ * nflush, WAIT_EVENT_DATA_FILE_FLUSH);
+
+ nblocks -= nflush;
+ blocknum += nflush;
}
-#else
- if (v->mdfd_vfd >= 0)
- FileClose(v->mdfd_vfd);
- pfree(v);
-#endif
}
/*
* mdread() -- Read the specified block from a relation.
*/
void
-mdread(SMgrRelation reln, BlockNumber blocknum, char *buffer)
+mdread(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
+ char *buffer)
{
- long seekpos;
+ off_t seekpos;
int nbytes;
MdfdVec *v;
- v = _mdfd_getseg(reln, blocknum, false, EXTENSION_FAIL);
+ TRACE_POSTGRESQL_SMGR_MD_READ_START(forknum, blocknum,
+ reln->smgr_rnode.node.spcNode,
+ reln->smgr_rnode.node.dbNode,
+ reln->smgr_rnode.node.relNode,
+ reln->smgr_rnode.backend);
-#ifndef LET_OS_MANAGE_FILESIZE
- seekpos = (long) (BLCKSZ * (blocknum % ((BlockNumber) RELSEG_SIZE)));
- Assert(seekpos < BLCKSZ * RELSEG_SIZE);
-#else
- seekpos = (long) (BLCKSZ * (blocknum));
-#endif
+ v = _mdfd_getseg(reln, forknum, blocknum, false,
+ EXTENSION_FAIL | EXTENSION_CREATE_RECOVERY);
- if (FileSeek(v->mdfd_vfd, seekpos, SEEK_SET) != seekpos)
- ereport(ERROR,
- (errcode_for_file_access(),
- errmsg("could not seek to block %u of relation %u/%u/%u: %m",
- blocknum,
- reln->smgr_rnode.spcNode,
- reln->smgr_rnode.dbNode,
- reln->smgr_rnode.relNode)));
+ seekpos = (off_t) BLCKSZ * (blocknum % ((BlockNumber) RELSEG_SIZE));
- if ((nbytes = FileRead(v->mdfd_vfd, buffer, BLCKSZ)) != BLCKSZ)
+ Assert(seekpos < (off_t) BLCKSZ * RELSEG_SIZE);
+
+ nbytes = FileRead(v->mdfd_vfd, buffer, BLCKSZ, seekpos, WAIT_EVENT_DATA_FILE_READ);
+
+ TRACE_POSTGRESQL_SMGR_MD_READ_DONE(forknum, blocknum,
+ reln->smgr_rnode.node.spcNode,
+ reln->smgr_rnode.node.dbNode,
+ reln->smgr_rnode.node.relNode,
+ reln->smgr_rnode.backend,
+ nbytes,
+ BLCKSZ);
+
+ if (nbytes != BLCKSZ)
{
if (nbytes < 0)
ereport(ERROR,
(errcode_for_file_access(),
- errmsg("could not read block %u of relation %u/%u/%u: %m",
- blocknum,
- reln->smgr_rnode.spcNode,
- reln->smgr_rnode.dbNode,
- reln->smgr_rnode.relNode)));
+ errmsg("could not read block %u in file \"%s\": %m",
+ blocknum, FilePathName(v->mdfd_vfd))));
+
/*
* Short read: we are at or past EOF, or we read a partial block at
* EOF. Normally this is an error; upper levels should never try to
- * read a nonexistent block. However, if zero_damaged_pages is ON
- * or we are InRecovery, we should instead return zeroes without
+ * read a nonexistent block. However, if zero_damaged_pages is ON or
+ * we are InRecovery, we should instead return zeroes without
* complaining. This allows, for example, the case of trying to
* update a block that was later truncated away.
*/
else
ereport(ERROR,
(errcode(ERRCODE_DATA_CORRUPTED),
- errmsg("could not read block %u of relation %u/%u/%u: read only %d of %d bytes",
- blocknum,
- reln->smgr_rnode.spcNode,
- reln->smgr_rnode.dbNode,
- reln->smgr_rnode.relNode,
+ errmsg("could not read block %u in file \"%s\": read only %d of %d bytes",
+ blocknum, FilePathName(v->mdfd_vfd),
nbytes, BLCKSZ)));
}
}
* use mdextend().
*/
void
-mdwrite(SMgrRelation reln, BlockNumber blocknum, char *buffer, bool isTemp)
+mdwrite(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
+ char *buffer, bool skipFsync)
{
- long seekpos;
+ off_t seekpos;
int nbytes;
MdfdVec *v;
/* This assert is too expensive to have on normally ... */
#ifdef CHECK_WRITE_VS_EXTEND
- Assert(blocknum < mdnblocks(reln));
+ Assert(blocknum < mdnblocks(reln, forknum));
#endif
- v = _mdfd_getseg(reln, blocknum, isTemp, EXTENSION_FAIL);
+ TRACE_POSTGRESQL_SMGR_MD_WRITE_START(forknum, blocknum,
+ reln->smgr_rnode.node.spcNode,
+ reln->smgr_rnode.node.dbNode,
+ reln->smgr_rnode.node.relNode,
+ reln->smgr_rnode.backend);
-#ifndef LET_OS_MANAGE_FILESIZE
- seekpos = (long) (BLCKSZ * (blocknum % ((BlockNumber) RELSEG_SIZE)));
- Assert(seekpos < BLCKSZ * RELSEG_SIZE);
-#else
- seekpos = (long) (BLCKSZ * (blocknum));
-#endif
+ v = _mdfd_getseg(reln, forknum, blocknum, skipFsync,
+ EXTENSION_FAIL | EXTENSION_CREATE_RECOVERY);
- if (FileSeek(v->mdfd_vfd, seekpos, SEEK_SET) != seekpos)
- ereport(ERROR,
- (errcode_for_file_access(),
- errmsg("could not seek to block %u of relation %u/%u/%u: %m",
- blocknum,
- reln->smgr_rnode.spcNode,
- reln->smgr_rnode.dbNode,
- reln->smgr_rnode.relNode)));
+ seekpos = (off_t) BLCKSZ * (blocknum % ((BlockNumber) RELSEG_SIZE));
+
+ Assert(seekpos < (off_t) BLCKSZ * RELSEG_SIZE);
+
+ nbytes = FileWrite(v->mdfd_vfd, buffer, BLCKSZ, seekpos, WAIT_EVENT_DATA_FILE_WRITE);
- if ((nbytes = FileWrite(v->mdfd_vfd, buffer, BLCKSZ)) != BLCKSZ)
+ TRACE_POSTGRESQL_SMGR_MD_WRITE_DONE(forknum, blocknum,
+ reln->smgr_rnode.node.spcNode,
+ reln->smgr_rnode.node.dbNode,
+ reln->smgr_rnode.node.relNode,
+ reln->smgr_rnode.backend,
+ nbytes,
+ BLCKSZ);
+
+ if (nbytes != BLCKSZ)
{
if (nbytes < 0)
ereport(ERROR,
(errcode_for_file_access(),
- errmsg("could not write block %u of relation %u/%u/%u: %m",
- blocknum,
- reln->smgr_rnode.spcNode,
- reln->smgr_rnode.dbNode,
- reln->smgr_rnode.relNode)));
+ errmsg("could not write block %u in file \"%s\": %m",
+ blocknum, FilePathName(v->mdfd_vfd))));
/* short write: complain appropriately */
ereport(ERROR,
(errcode(ERRCODE_DISK_FULL),
- errmsg("could not write block %u of relation %u/%u/%u: wrote only %d of %d bytes",
+ errmsg("could not write block %u in file \"%s\": wrote only %d of %d bytes",
blocknum,
- reln->smgr_rnode.spcNode,
- reln->smgr_rnode.dbNode,
- reln->smgr_rnode.relNode,
+ FilePathName(v->mdfd_vfd),
nbytes, BLCKSZ),
errhint("Check free disk space.")));
}
- if (!isTemp)
- register_dirty_segment(reln, v);
+ if (!skipFsync && !SmgrIsTemp(reln))
+ register_dirty_segment(reln, forknum, v);
}
/*
* mdnblocks() -- Get the number of blocks stored in a relation.
*
* Important side effect: all active segments of the relation are opened
- * and added to the mdfd_chain list. If this routine has not been
+ * and added to the mdfd_seg_fds array. If this routine has not been
* called, then only segments up to the last one actually touched
- * are present in the chain.
+ * are present in the array.
*/
BlockNumber
-mdnblocks(SMgrRelation reln)
+mdnblocks(SMgrRelation reln, ForkNumber forknum)
{
- MdfdVec *v = mdopen(reln, EXTENSION_FAIL);
-
-#ifndef LET_OS_MANAGE_FILESIZE
+ MdfdVec *v = mdopen(reln, forknum, EXTENSION_FAIL);
BlockNumber nblocks;
BlockNumber segno = 0;
+ /* mdopen has opened the first segment */
+ Assert(reln->md_num_open_segs[forknum] > 0);
+
/*
- * Skip through any segments that aren't the last one, to avoid redundant
- * seeks on them. We have previously verified that these segments are
- * exactly RELSEG_SIZE long, and it's useless to recheck that each time.
+ * Start from the last open segments, to avoid redundant seeks. We have
+ * previously verified that these segments are exactly RELSEG_SIZE long,
+ * and it's useless to recheck that each time.
*
* NOTE: this assumption could only be wrong if another backend has
- * truncated the relation. We rely on higher code levels to handle that
+ * truncated the relation. We rely on higher code levels to handle that
* scenario by closing and re-opening the md fd, which is handled via
- * relcache flush. (Since the bgwriter doesn't participate in relcache
- * flush, it could have segment chain entries for inactive segments;
- * that's OK because the bgwriter never needs to compute relation size.)
+ * relcache flush. (Since the checkpointer doesn't participate in
+ * relcache flush, it could have segment entries for inactive segments;
+ * that's OK because the checkpointer never needs to compute relation
+ * size.)
*/
- while (v->mdfd_chain != NULL)
- {
- segno++;
- v = v->mdfd_chain;
- }
+ segno = reln->md_num_open_segs[forknum] - 1;
+ v = &reln->md_seg_fds[forknum][segno];
for (;;)
{
- nblocks = _mdnblocks(reln, v);
+ nblocks = _mdnblocks(reln, forknum, v);
if (nblocks > ((BlockNumber) RELSEG_SIZE))
elog(FATAL, "segment too big");
if (nblocks < ((BlockNumber) RELSEG_SIZE))
*/
segno++;
- if (v->mdfd_chain == NULL)
- {
- /*
- * Because we pass O_CREAT, we will create the next segment (with
- * zero length) immediately, if the last segment is of length
- * RELSEG_SIZE. While perhaps not strictly necessary, this keeps
- * the logic simple.
- */
- v->mdfd_chain = _mdfd_openseg(reln, segno, O_CREAT);
- if (v->mdfd_chain == NULL)
- ereport(ERROR,
- (errcode_for_file_access(),
- errmsg("could not open segment %u of relation %u/%u/%u: %m",
- segno,
- reln->smgr_rnode.spcNode,
- reln->smgr_rnode.dbNode,
- reln->smgr_rnode.relNode)));
- }
-
- v = v->mdfd_chain;
+ /*
+ * We used to pass O_CREAT here, but that's has the disadvantage that
+ * it might create a segment which has vanished through some operating
+ * system misadventure. In such a case, creating the segment here
+ * undermines _mdfd_getseg's attempts to notice and report an error
+ * upon access to a missing segment.
+ */
+ v = _mdfd_openseg(reln, forknum, segno, 0);
+ if (v == NULL)
+ return segno * ((BlockNumber) RELSEG_SIZE);
}
-#else
- return _mdnblocks(reln, v);
-#endif
}
/*
* mdtruncate() -- Truncate relation to specified number of blocks.
*/
void
-mdtruncate(SMgrRelation reln, BlockNumber nblocks, bool isTemp)
+mdtruncate(SMgrRelation reln, ForkNumber forknum, BlockNumber nblocks)
{
- MdfdVec *v;
BlockNumber curnblk;
-
-#ifndef LET_OS_MANAGE_FILESIZE
BlockNumber priorblocks;
-#endif
+ int curopensegs;
/*
- * NOTE: mdnblocks makes sure we have opened all active segments, so
- * that truncation loop will get them all!
+ * NOTE: mdnblocks makes sure we have opened all active segments, so that
+ * truncation loop will get them all!
*/
- curnblk = mdnblocks(reln);
+ curnblk = mdnblocks(reln, forknum);
if (nblocks > curnblk)
{
/* Bogus request ... but no complaint if InRecovery */
if (InRecovery)
return;
ereport(ERROR,
- (errmsg("could not truncate relation %u/%u/%u to %u blocks: it's only %u blocks now",
- reln->smgr_rnode.spcNode,
- reln->smgr_rnode.dbNode,
- reln->smgr_rnode.relNode,
+ (errmsg("could not truncate file \"%s\" to %u blocks: it's only %u blocks now",
+ relpath(reln->smgr_rnode, forknum),
nblocks, curnblk)));
}
if (nblocks == curnblk)
return; /* no work */
- v = mdopen(reln, EXTENSION_FAIL);
-
-#ifndef LET_OS_MANAGE_FILESIZE
- priorblocks = 0;
- while (v != NULL)
+ /*
+ * Truncate segments, starting at the last one. Starting at the end makes
+ * managing the memory for the fd array easier, should there be errors.
+ */
+ curopensegs = reln->md_num_open_segs[forknum];
+ while (curopensegs > 0)
{
- MdfdVec *ov = v;
+ MdfdVec *v;
+
+ priorblocks = (curopensegs - 1) * RELSEG_SIZE;
+
+ v = &reln->md_seg_fds[forknum][curopensegs - 1];
if (priorblocks > nblocks)
{
/*
- * This segment is no longer active (and has already been
- * unlinked from the mdfd_chain). We truncate the file, but do
+ * This segment is no longer active. We truncate the file, but do
* not delete it, for reasons explained in the header comments.
*/
- if (FileTruncate(v->mdfd_vfd, 0) < 0)
+ if (FileTruncate(v->mdfd_vfd, 0, WAIT_EVENT_DATA_FILE_TRUNCATE) < 0)
ereport(ERROR,
(errcode_for_file_access(),
- errmsg("could not truncate relation %u/%u/%u to %u blocks: %m",
- reln->smgr_rnode.spcNode,
- reln->smgr_rnode.dbNode,
- reln->smgr_rnode.relNode,
- nblocks)));
- if (!isTemp)
- register_dirty_segment(reln, v);
- v = v->mdfd_chain;
- Assert(ov != reln->md_fd); /* we never drop the 1st segment */
- pfree(ov);
+ errmsg("could not truncate file \"%s\": %m",
+ FilePathName(v->mdfd_vfd))));
+
+ if (!SmgrIsTemp(reln))
+ register_dirty_segment(reln, forknum, v);
+
+ /* we never drop the 1st segment */
+ Assert(v != &reln->md_seg_fds[forknum][0]);
+
+ FileClose(v->mdfd_vfd);
+ _fdvec_resize(reln, forknum, curopensegs - 1);
}
else if (priorblocks + ((BlockNumber) RELSEG_SIZE) > nblocks)
{
/*
* This is the last segment we want to keep. Truncate the file to
- * the right length, and clear chain link that points to any
- * remaining segments (which we shall zap). NOTE: if nblocks is
- * exactly a multiple K of RELSEG_SIZE, we will truncate the K+1st
- * segment to 0 length but keep it. This adheres to the invariant
- * given in the header comments.
+ * the right length. NOTE: if nblocks is exactly a multiple K of
+ * RELSEG_SIZE, we will truncate the K+1st segment to 0 length but
+ * keep it. This adheres to the invariant given in the header
+ * comments.
*/
BlockNumber lastsegblocks = nblocks - priorblocks;
- if (FileTruncate(v->mdfd_vfd, lastsegblocks * BLCKSZ) < 0)
+ if (FileTruncate(v->mdfd_vfd, (off_t) lastsegblocks * BLCKSZ, WAIT_EVENT_DATA_FILE_TRUNCATE) < 0)
ereport(ERROR,
(errcode_for_file_access(),
- errmsg("could not truncate relation %u/%u/%u to %u blocks: %m",
- reln->smgr_rnode.spcNode,
- reln->smgr_rnode.dbNode,
- reln->smgr_rnode.relNode,
+ errmsg("could not truncate file \"%s\" to %u blocks: %m",
+ FilePathName(v->mdfd_vfd),
nblocks)));
- if (!isTemp)
- register_dirty_segment(reln, v);
- v = v->mdfd_chain;
- ov->mdfd_chain = NULL;
+ if (!SmgrIsTemp(reln))
+ register_dirty_segment(reln, forknum, v);
}
else
{
/*
- * We still need this segment and 0 or more blocks beyond it, so
- * nothing to do here.
+ * We still need this segment, so nothing to do for this and any
+ * earlier segment.
*/
- v = v->mdfd_chain;
+ break;
}
- priorblocks += RELSEG_SIZE;
+ curopensegs--;
}
-#else
- if (FileTruncate(v->mdfd_vfd, nblocks * BLCKSZ) < 0)
- ereport(ERROR,
- (errcode_for_file_access(),
- errmsg("could not truncate relation %u/%u/%u to %u blocks: %m",
- reln->smgr_rnode.spcNode,
- reln->smgr_rnode.dbNode,
- reln->smgr_rnode.relNode,
- nblocks)));
- if (!isTemp)
- register_dirty_segment(reln, v);
-#endif
}
/*
* nothing of dirty buffers that may exist inside the buffer manager.
*/
void
-mdimmedsync(SMgrRelation reln)
+mdimmedsync(SMgrRelation reln, ForkNumber forknum)
{
- MdfdVec *v;
- BlockNumber curnblk;
+ int segno;
/*
- * NOTE: mdnblocks makes sure we have opened all active segments, so
- * that fsync loop will get them all!
+ * NOTE: mdnblocks makes sure we have opened all active segments, so that
+ * fsync loop will get them all!
*/
- curnblk = mdnblocks(reln);
+ mdnblocks(reln, forknum);
- v = mdopen(reln, EXTENSION_FAIL);
+ segno = reln->md_num_open_segs[forknum];
-#ifndef LET_OS_MANAGE_FILESIZE
- while (v != NULL)
+ while (segno > 0)
{
- if (FileSync(v->mdfd_vfd) < 0)
- ereport(ERROR,
+ MdfdVec *v = &reln->md_seg_fds[forknum][segno - 1];
+
+ if (FileSync(v->mdfd_vfd, WAIT_EVENT_DATA_FILE_IMMEDIATE_SYNC) < 0)
+ ereport(data_sync_elevel(ERROR),
(errcode_for_file_access(),
- errmsg("could not fsync segment %u of relation %u/%u/%u: %m",
- v->mdfd_segno,
- reln->smgr_rnode.spcNode,
- reln->smgr_rnode.dbNode,
- reln->smgr_rnode.relNode)));
- v = v->mdfd_chain;
+ errmsg("could not fsync file \"%s\": %m",
+ FilePathName(v->mdfd_vfd))));
+ segno--;
}
-#else
- if (FileSync(v->mdfd_vfd) < 0)
- ereport(ERROR,
- (errcode_for_file_access(),
- errmsg("could not fsync segment %u of relation %u/%u/%u: %m",
- v->mdfd_segno,
- reln->smgr_rnode.spcNode,
- reln->smgr_rnode.dbNode,
- reln->smgr_rnode.relNode)));
-#endif
}
/*
* mdsync() -- Sync previous writes to stable storage.
- *
- * This is only called during checkpoints, and checkpoints should only
- * occur in processes that have created a pendingOpsTable.
*/
void
mdsync(void)
{
- bool need_retry;
+ static bool mdsync_in_progress = false;
+ HASH_SEQ_STATUS hstat;
+ PendingOperationEntry *entry;
+ int absorb_counter;
+
+ /* Statistics on sync times */
+ int processed = 0;
+ instr_time sync_start,
+ sync_end,
+ sync_diff;
+ uint64 elapsed;
+ uint64 longest = 0;
+ uint64 total_elapsed = 0;
+
+ /*
+ * This is only called during checkpoints, and checkpoints should only
+ * occur in processes that have created a pendingOpsTable.
+ */
if (!pendingOpsTable)
elog(ERROR, "cannot sync without a pendingOpsTable");
/*
- * The fsync table could contain requests to fsync relations that have
- * been deleted (unlinked) by the time we get to them. Rather than
- * just hoping an ENOENT (or EACCES on Windows) error can be ignored,
- * what we will do is retry the whole process after absorbing fsync
- * request messages again. Since mdunlink() queues a "revoke" message
- * before actually unlinking, the fsync request is guaranteed to be gone
- * the second time if it really was this case. DROP DATABASE likewise
- * has to tell us to forget fsync requests before it starts deletions.
+ * If we are in the checkpointer, the sync had better include all fsync
+ * requests that were queued by backends up to this point. The tightest
+ * race condition that could occur is that a buffer that must be written
+ * and fsync'd for the checkpoint could have been dumped by a backend just
+ * before it was visited by BufferSync(). We know the backend will have
+ * queued an fsync request before clearing the buffer's dirtybit, so we
+ * are safe as long as we do an Absorb after completing BufferSync().
*/
- do {
- HASH_SEQ_STATUS hstat;
- PendingOperationEntry *entry;
- int absorb_counter;
+ AbsorbFsyncRequests();
- need_retry = false;
+ /*
+ * To avoid excess fsync'ing (in the worst case, maybe a never-terminating
+ * checkpoint), we want to ignore fsync requests that are entered into the
+ * hashtable after this point --- they should be processed next time,
+ * instead. We use mdsync_cycle_ctr to tell old entries apart from new
+ * ones: new ones will have cycle_ctr equal to the incremented value of
+ * mdsync_cycle_ctr.
+ *
+ * In normal circumstances, all entries present in the table at this point
+ * will have cycle_ctr exactly equal to the current (about to be old)
+ * value of mdsync_cycle_ctr. However, if we fail partway through the
+ * fsync'ing loop, then older values of cycle_ctr might remain when we
+ * come back here to try again. Repeated checkpoint failures would
+ * eventually wrap the counter around to the point where an old entry
+ * might appear new, causing us to skip it, possibly allowing a checkpoint
+ * to succeed that should not have. To forestall wraparound, any time the
+ * previous mdsync() failed to complete, run through the table and
+ * forcibly set cycle_ctr = mdsync_cycle_ctr.
+ *
+ * Think not to merge this loop with the main loop, as the problem is
+ * exactly that that loop may fail before having visited all the entries.
+ * From a performance point of view it doesn't matter anyway, as this path
+ * will never be taken in a system that's functioning normally.
+ */
+ if (mdsync_in_progress)
+ {
+ /* prior try failed, so update any stale cycle_ctr values */
+ hash_seq_init(&hstat, pendingOpsTable);
+ while ((entry = (PendingOperationEntry *) hash_seq_search(&hstat)) != NULL)
+ {
+ entry->cycle_ctr = mdsync_cycle_ctr;
+ }
+ }
+
+ /* Advance counter so that new hashtable entries are distinguishable */
+ mdsync_cycle_ctr++;
+
+ /* Set flag to detect failure if we don't reach the end of the loop */
+ mdsync_in_progress = true;
+
+ /* Now scan the hashtable for fsync requests to process */
+ absorb_counter = FSYNCS_PER_ABSORB;
+ hash_seq_init(&hstat, pendingOpsTable);
+ while ((entry = (PendingOperationEntry *) hash_seq_search(&hstat)) != NULL)
+ {
+ ForkNumber forknum;
/*
- * If we are in the bgwriter, the sync had better include all fsync
- * requests that were queued by backends before the checkpoint REDO
- * point was determined. We go that a little better by accepting all
- * requests queued up to the point where we start fsync'ing.
+ * If the entry is new then don't process it this time; it might
+ * contain multiple fsync-request bits, but they are all new. Note
+ * "continue" bypasses the hash-remove call at the bottom of the loop.
*/
- AbsorbFsyncRequests();
+ if (entry->cycle_ctr == mdsync_cycle_ctr)
+ continue;
- absorb_counter = FSYNCS_PER_ABSORB;
- hash_seq_init(&hstat, pendingOpsTable);
- while ((entry = (PendingOperationEntry *) hash_seq_search(&hstat)) != NULL)
+ /* Else assert we haven't missed it */
+ Assert((CycleCtr) (entry->cycle_ctr + 1) == mdsync_cycle_ctr);
+
+ /*
+ * Scan over the forks and segments represented by the entry.
+ *
+ * The bitmap manipulations are slightly tricky, because we can call
+ * AbsorbFsyncRequests() inside the loop and that could result in
+ * bms_add_member() modifying and even re-palloc'ing the bitmapsets.
+ * So we detach it, but if we fail we'll merge it with any new
+ * requests that have arrived in the meantime.
+ */
+ for (forknum = 0; forknum <= MAX_FORKNUM; forknum++)
{
- /*
- * If fsync is off then we don't have to bother opening the file
- * at all. (We delay checking until this point so that changing
- * fsync on the fly behaves sensibly.)
- */
- if (enableFsync)
+ Bitmapset *requests = entry->requests[forknum];
+ int segno;
+
+ entry->requests[forknum] = NULL;
+ entry->canceled[forknum] = false;
+
+ segno = -1;
+ while ((segno = bms_next_member(requests, segno)) >= 0)
{
- SMgrRelation reln;
- MdfdVec *seg;
+ int failures;
/*
- * If in bgwriter, we want to absorb pending requests every so
- * often to prevent overflow of the fsync request queue. This
- * could result in deleting the current entry out from under
- * our hashtable scan, so the procedure is to fall out of the
- * scan and start over from the top of the function.
+ * If fsync is off then we don't have to bother opening the
+ * file at all. (We delay checking until this point so that
+ * changing fsync on the fly behaves sensibly.)
*/
- if (--absorb_counter <= 0)
- {
- need_retry = true;
- break;
- }
+ if (!enableFsync)
+ continue;
/*
- * Find or create an smgr hash entry for this relation. This
- * may seem a bit unclean -- md calling smgr? But it's really
- * the best solution. It ensures that the open file reference
- * isn't permanently leaked if we get an error here. (You may
- * say "but an unreferenced SMgrRelation is still a leak!" Not
- * really, because the only case in which a checkpoint is done
- * by a process that isn't about to shut down is in the
- * bgwriter, and it will periodically do smgrcloseall(). This
- * fact justifies our not closing the reln in the success path
- * either, which is a good thing since in non-bgwriter cases
- * we couldn't safely do that.) Furthermore, in many cases
- * the relation will have been dirtied through this same smgr
- * relation, and so we can save a file open/close cycle.
+ * If in checkpointer, we want to absorb pending requests
+ * every so often to prevent overflow of the fsync request
+ * queue. It is unspecified whether newly-added entries will
+ * be visited by hash_seq_search, but we don't care since we
+ * don't need to process them anyway.
*/
- reln = smgropen(entry->tag.rnode);
+ if (--absorb_counter <= 0)
+ {
+ AbsorbFsyncRequests();
+ absorb_counter = FSYNCS_PER_ABSORB;
+ }
/*
- * It is possible that the relation has been dropped or
- * truncated since the fsync request was entered. Therefore,
- * allow ENOENT, but only if we didn't fail once already on
- * this file. This applies both during _mdfd_getseg() and
- * during FileSync, since fd.c might have closed the file
- * behind our back.
+ * The fsync table could contain requests to fsync segments
+ * that have been deleted (unlinked) by the time we get to
+ * them. Rather than just hoping an ENOENT (or EACCES on
+ * Windows) error can be ignored, what we do on error is
+ * absorb pending requests and then retry. Since mdunlink()
+ * queues a "cancel" message before actually unlinking, the
+ * fsync request is guaranteed to be marked canceled after the
+ * absorb if it really was this case. DROP DATABASE likewise
+ * has to tell us to forget fsync requests before it starts
+ * deletions.
*/
- seg = _mdfd_getseg(reln,
- entry->tag.segno * ((BlockNumber) RELSEG_SIZE),
- false, EXTENSION_RETURN_NULL);
- if (seg == NULL ||
- FileSync(seg->mdfd_vfd) < 0)
+ for (failures = 0;; failures++) /* loop exits at "break" */
{
+ SMgrRelation reln;
+ MdfdVec *seg;
+ char *path;
+ int save_errno;
+
/*
- * XXX is there any point in allowing more than one try?
+ * Find or create an smgr hash entry for this relation.
+ * This may seem a bit unclean -- md calling smgr? But
+ * it's really the best solution. It ensures that the
+ * open file reference isn't permanently leaked if we get
+ * an error here. (You may say "but an unreferenced
+ * SMgrRelation is still a leak!" Not really, because the
+ * only case in which a checkpoint is done by a process
+ * that isn't about to shut down is in the checkpointer,
+ * and it will periodically do smgrcloseall(). This fact
+ * justifies our not closing the reln in the success path
+ * either, which is a good thing since in non-checkpointer
+ * cases we couldn't safely do that.)
+ */
+ reln = smgropen(entry->rnode, InvalidBackendId);
+
+ /* Attempt to open and fsync the target segment */
+ seg = _mdfd_getseg(reln, forknum,
+ (BlockNumber) segno * (BlockNumber) RELSEG_SIZE,
+ false,
+ EXTENSION_RETURN_NULL
+ | EXTENSION_DONT_CHECK_SIZE);
+
+ INSTR_TIME_SET_CURRENT(sync_start);
+
+ if (seg != NULL &&
+ FileSync(seg->mdfd_vfd, WAIT_EVENT_DATA_FILE_SYNC) >= 0)
+ {
+ /* Success; update statistics about sync timing */
+ INSTR_TIME_SET_CURRENT(sync_end);
+ sync_diff = sync_end;
+ INSTR_TIME_SUBTRACT(sync_diff, sync_start);
+ elapsed = INSTR_TIME_GET_MICROSEC(sync_diff);
+ if (elapsed > longest)
+ longest = elapsed;
+ total_elapsed += elapsed;
+ processed++;
+ requests = bms_del_member(requests, segno);
+ if (log_checkpoints)
+ elog(DEBUG1, "checkpoint sync: number=%d file=%s time=%.3f msec",
+ processed,
+ FilePathName(seg->mdfd_vfd),
+ (double) elapsed / 1000);
+
+ break; /* out of retry loop */
+ }
+
+ /* Compute file name for use in message */
+ save_errno = errno;
+ path = _mdfd_segpath(reln, forknum, (BlockNumber) segno);
+ errno = save_errno;
+
+ /*
+ * It is possible that the relation has been dropped or
+ * truncated since the fsync request was entered.
+ * Therefore, allow ENOENT, but only if we didn't fail
+ * already on this file. This applies both for
+ * _mdfd_getseg() and for FileSync, since fd.c might have
+ * closed the file behind our back.
+ *
+ * XXX is there any point in allowing more than one retry?
* Don't see one at the moment, but easy to change the
* test here if so.
*/
if (!FILE_POSSIBLY_DELETED(errno) ||
- ++(entry->failures) > 1)
- ereport(ERROR,
+ failures > 0)
+ {
+ Bitmapset *new_requests;
+
+ /*
+ * We need to merge these unsatisfied requests with
+ * any others that have arrived since we started.
+ */
+ new_requests = entry->requests[forknum];
+ entry->requests[forknum] =
+ bms_join(new_requests, requests);
+
+ errno = save_errno;
+ ereport(data_sync_elevel(ERROR),
(errcode_for_file_access(),
- errmsg("could not fsync segment %u of relation %u/%u/%u: %m",
- entry->tag.segno,
- entry->tag.rnode.spcNode,
- entry->tag.rnode.dbNode,
- entry->tag.rnode.relNode)));
+ errmsg("could not fsync file \"%s\": %m",
+ path)));
+ }
else
ereport(DEBUG1,
(errcode_for_file_access(),
- errmsg("could not fsync segment %u of relation %u/%u/%u, but retrying: %m",
- entry->tag.segno,
- entry->tag.rnode.spcNode,
- entry->tag.rnode.dbNode,
- entry->tag.rnode.relNode)));
- need_retry = true;
- continue; /* don't delete the hashtable entry */
- }
+ errmsg("could not fsync file \"%s\" but retrying: %m",
+ path)));
+ pfree(path);
+
+ /*
+ * Absorb incoming requests and check to see if a cancel
+ * arrived for this relation fork.
+ */
+ AbsorbFsyncRequests();
+ absorb_counter = FSYNCS_PER_ABSORB; /* might as well... */
+
+ if (entry->canceled[forknum])
+ break;
+ } /* end retry loop */
}
+ bms_free(requests);
+ }
- /* Okay, delete this entry */
- if (hash_search(pendingOpsTable, &entry->tag,
+ /*
+ * We've finished everything that was requested before we started to
+ * scan the entry. If no new requests have been inserted meanwhile,
+ * remove the entry. Otherwise, update its cycle counter, as all the
+ * requests now in it must have arrived during this cycle.
+ */
+ for (forknum = 0; forknum <= MAX_FORKNUM; forknum++)
+ {
+ if (entry->requests[forknum] != NULL)
+ break;
+ }
+ if (forknum <= MAX_FORKNUM)
+ entry->cycle_ctr = mdsync_cycle_ctr;
+ else
+ {
+ /* Okay to remove it */
+ if (hash_search(pendingOpsTable, &entry->rnode,
HASH_REMOVE, NULL) == NULL)
elog(ERROR, "pendingOpsTable corrupted");
}
- } while (need_retry);
+ } /* end loop over hashtable entries */
+
+ /* Return sync performance metrics for report at checkpoint end */
+ CheckpointStats.ckpt_sync_rels = processed;
+ CheckpointStats.ckpt_longest_sync = longest;
+ CheckpointStats.ckpt_agg_sync_time = total_elapsed;
+
+ /* Flag successful completion of mdsync */
+ mdsync_in_progress = false;
+}
+
+/*
+ * mdpreckpt() -- Do pre-checkpoint work
+ *
+ * To distinguish unlink requests that arrived before this checkpoint
+ * started from those that arrived during the checkpoint, we use a cycle
+ * counter similar to the one we use for fsync requests. That cycle
+ * counter is incremented here.
+ *
+ * This must be called *before* the checkpoint REDO point is determined.
+ * That ensures that we won't delete files too soon.
+ *
+ * Note that we can't do anything here that depends on the assumption
+ * that the checkpoint will be completed.
+ */
+void
+mdpreckpt(void)
+{
+ /*
+ * Any unlink requests arriving after this point will be assigned the next
+ * cycle counter, and won't be unlinked until next checkpoint.
+ */
+ mdckpt_cycle_ctr++;
+}
+
+/*
+ * mdpostckpt() -- Do post-checkpoint work
+ *
+ * Remove any lingering files that can now be safely removed.
+ */
+void
+mdpostckpt(void)
+{
+ int absorb_counter;
+
+ absorb_counter = UNLINKS_PER_ABSORB;
+ while (pendingUnlinks != NIL)
+ {
+ PendingUnlinkEntry *entry = (PendingUnlinkEntry *) linitial(pendingUnlinks);
+ char *path;
+
+ /*
+ * New entries are appended to the end, so if the entry is new we've
+ * reached the end of old entries.
+ *
+ * Note: if just the right number of consecutive checkpoints fail, we
+ * could be fooled here by cycle_ctr wraparound. However, the only
+ * consequence is that we'd delay unlinking for one more checkpoint,
+ * which is perfectly tolerable.
+ */
+ if (entry->cycle_ctr == mdckpt_cycle_ctr)
+ break;
+
+ /* Unlink the file */
+ path = relpathperm(entry->rnode, MAIN_FORKNUM);
+ if (unlink(path) < 0)
+ {
+ /*
+ * There's a race condition, when the database is dropped at the
+ * same time that we process the pending unlink requests. If the
+ * DROP DATABASE deletes the file before we do, we will get ENOENT
+ * here. rmtree() also has to ignore ENOENT errors, to deal with
+ * the possibility that we delete the file first.
+ */
+ if (errno != ENOENT)
+ ereport(WARNING,
+ (errcode_for_file_access(),
+ errmsg("could not remove file \"%s\": %m", path)));
+ }
+ pfree(path);
+
+ /* And remove the list entry */
+ pendingUnlinks = list_delete_first(pendingUnlinks);
+ pfree(entry);
+
+ /*
+ * As in mdsync, we don't want to stop absorbing fsync requests for a
+ * long time when there are many deletions to be done. We can safely
+ * call AbsorbFsyncRequests() at this point in the loop (note it might
+ * try to delete list entries).
+ */
+ if (--absorb_counter <= 0)
+ {
+ AbsorbFsyncRequests();
+ absorb_counter = UNLINKS_PER_ABSORB;
+ }
+ }
}
/*
*
* If there is a local pending-ops table, just make an entry in it for
* mdsync to process later. Otherwise, try to pass off the fsync request
- * to the background writer process. If that fails, just do the fsync
- * locally before returning (we expect this will not happen often enough
+ * to the checkpointer process. If that fails, just do the fsync
+ * locally before returning (we hope this will not happen often enough
* to be a performance problem).
*/
static void
-register_dirty_segment(SMgrRelation reln, MdfdVec *seg)
+register_dirty_segment(SMgrRelation reln, ForkNumber forknum, MdfdVec *seg)
{
+ /* Temp relations should never be fsync'd */
+ Assert(!SmgrIsTemp(reln));
+
if (pendingOpsTable)
{
/* push it into local pending-ops table */
- RememberFsyncRequest(reln->smgr_rnode, seg->mdfd_segno);
+ RememberFsyncRequest(reln->smgr_rnode.node, forknum, seg->mdfd_segno);
}
else
{
- if (ForwardFsyncRequest(reln->smgr_rnode, seg->mdfd_segno))
+ if (ForwardFsyncRequest(reln->smgr_rnode.node, forknum, seg->mdfd_segno))
return; /* passed it off successfully */
- if (FileSync(seg->mdfd_vfd) < 0)
- ereport(ERROR,
+ ereport(DEBUG1,
+ (errmsg("could not forward fsync request because request queue is full")));
+
+ if (FileSync(seg->mdfd_vfd, WAIT_EVENT_DATA_FILE_SYNC) < 0)
+ ereport(data_sync_elevel(ERROR),
(errcode_for_file_access(),
- errmsg("could not fsync segment %u of relation %u/%u/%u: %m",
- seg->mdfd_segno,
- reln->smgr_rnode.spcNode,
- reln->smgr_rnode.dbNode,
- reln->smgr_rnode.relNode)));
+ errmsg("could not fsync file \"%s\": %m",
+ FilePathName(seg->mdfd_vfd))));
+ }
+}
+
+/*
+ * register_unlink() -- Schedule a file to be deleted after next checkpoint
+ *
+ * We don't bother passing in the fork number, because this is only used
+ * with main forks.
+ *
+ * As with register_dirty_segment, this could involve either a local or
+ * a remote pending-ops table.
+ */
+static void
+register_unlink(RelFileNodeBackend rnode)
+{
+ /* Should never be used with temp relations */
+ Assert(!RelFileNodeBackendIsTemp(rnode));
+
+ if (pendingOpsTable)
+ {
+ /* push it into local pending-ops table */
+ RememberFsyncRequest(rnode.node, MAIN_FORKNUM,
+ UNLINK_RELATION_REQUEST);
+ }
+ else
+ {
+ /*
+ * Notify the checkpointer about it. If we fail to queue the request
+ * message, we have to sleep and try again, because we can't simply
+ * delete the file now. Ugly, but hopefully won't happen often.
+ *
+ * XXX should we just leave the file orphaned instead?
+ */
+ Assert(IsUnderPostmaster);
+ while (!ForwardFsyncRequest(rnode.node, MAIN_FORKNUM,
+ UNLINK_RELATION_REQUEST))
+ pg_usleep(10000L); /* 10 msec seems a good number */
}
}
/*
- * RememberFsyncRequest() -- callback from bgwriter side of fsync request
+ * RememberFsyncRequest() -- callback from checkpointer side of fsync request
*
- * We stuff the fsync request into the local hash table for execution
- * during the bgwriter's next checkpoint.
+ * We stuff fsync requests into the local hash table for execution
+ * during the checkpointer's next checkpoint. UNLINK requests go into a
+ * separate linked list, however, because they get processed separately.
*
* The range of possible segment numbers is way less than the range of
* BlockNumber, so we can reserve high values of segno for special purposes.
- * We define two: FORGET_RELATION_FSYNC means to drop pending fsyncs for
- * a relation, and FORGET_DATABASE_FSYNC means to drop pending fsyncs for
- * a whole database. (These are a tad slow because the hash table has to be
- * searched linearly, but it doesn't seem worth rethinking the table structure
- * for them.)
+ * We define three:
+ * - FORGET_RELATION_FSYNC means to cancel pending fsyncs for a relation,
+ * either for one fork, or all forks if forknum is InvalidForkNumber
+ * - FORGET_DATABASE_FSYNC means to cancel pending fsyncs for a whole database
+ * - UNLINK_RELATION_REQUEST is a request to delete the file after the next
+ * checkpoint.
+ * Note also that we're assuming real segment numbers don't exceed INT_MAX.
+ *
+ * (Handling FORGET_DATABASE_FSYNC requests is a tad slow because the hash
+ * table has to be searched linearly, but dropping a database is a pretty
+ * heavyweight operation anyhow, so we'll live with it.)
*/
void
-RememberFsyncRequest(RelFileNode rnode, BlockNumber segno)
+RememberFsyncRequest(RelFileNode rnode, ForkNumber forknum, BlockNumber segno)
{
Assert(pendingOpsTable);
if (segno == FORGET_RELATION_FSYNC)
{
- /* Remove any pending requests for the entire relation */
- HASH_SEQ_STATUS hstat;
+ /* Remove any pending requests for the relation (one or all forks) */
PendingOperationEntry *entry;
- hash_seq_init(&hstat, pendingOpsTable);
- while ((entry = (PendingOperationEntry *) hash_seq_search(&hstat)) != NULL)
+ entry = (PendingOperationEntry *) hash_search(pendingOpsTable,
+ &rnode,
+ HASH_FIND,
+ NULL);
+ if (entry)
{
- if (RelFileNodeEquals(entry->tag.rnode, rnode))
+ /*
+ * We can't just delete the entry since mdsync could have an
+ * active hashtable scan. Instead we delete the bitmapsets; this
+ * is safe because of the way mdsync is coded. We also set the
+ * "canceled" flags so that mdsync can tell that a cancel arrived
+ * for the fork(s).
+ */
+ if (forknum == InvalidForkNumber)
{
- /* Okay, delete this entry */
- if (hash_search(pendingOpsTable, &entry->tag,
- HASH_REMOVE, NULL) == NULL)
- elog(ERROR, "pendingOpsTable corrupted");
+ /* remove requests for all forks */
+ for (forknum = 0; forknum <= MAX_FORKNUM; forknum++)
+ {
+ bms_free(entry->requests[forknum]);
+ entry->requests[forknum] = NULL;
+ entry->canceled[forknum] = true;
+ }
+ }
+ else
+ {
+ /* remove requests for single fork */
+ bms_free(entry->requests[forknum]);
+ entry->requests[forknum] = NULL;
+ entry->canceled[forknum] = true;
}
}
}
/* Remove any pending requests for the entire database */
HASH_SEQ_STATUS hstat;
PendingOperationEntry *entry;
+ ListCell *cell,
+ *prev,
+ *next;
+ /* Remove fsync requests */
hash_seq_init(&hstat, pendingOpsTable);
while ((entry = (PendingOperationEntry *) hash_seq_search(&hstat)) != NULL)
{
- if (entry->tag.rnode.dbNode == rnode.dbNode)
+ if (entry->rnode.dbNode == rnode.dbNode)
+ {
+ /* remove requests for all forks */
+ for (forknum = 0; forknum <= MAX_FORKNUM; forknum++)
+ {
+ bms_free(entry->requests[forknum]);
+ entry->requests[forknum] = NULL;
+ entry->canceled[forknum] = true;
+ }
+ }
+ }
+
+ /* Remove unlink requests */
+ prev = NULL;
+ for (cell = list_head(pendingUnlinks); cell; cell = next)
+ {
+ PendingUnlinkEntry *entry = (PendingUnlinkEntry *) lfirst(cell);
+
+ next = lnext(cell);
+ if (entry->rnode.dbNode == rnode.dbNode)
{
- /* Okay, delete this entry */
- if (hash_search(pendingOpsTable, &entry->tag,
- HASH_REMOVE, NULL) == NULL)
- elog(ERROR, "pendingOpsTable corrupted");
+ pendingUnlinks = list_delete_cell(pendingUnlinks, cell, prev);
+ pfree(entry);
}
+ else
+ prev = cell;
}
}
+ else if (segno == UNLINK_RELATION_REQUEST)
+ {
+ /* Unlink request: put it in the linked list */
+ MemoryContext oldcxt = MemoryContextSwitchTo(pendingOpsCxt);
+ PendingUnlinkEntry *entry;
+
+ /* PendingUnlinkEntry doesn't store forknum, since it's always MAIN */
+ Assert(forknum == MAIN_FORKNUM);
+
+ entry = palloc(sizeof(PendingUnlinkEntry));
+ entry->rnode = rnode;
+ entry->cycle_ctr = mdckpt_cycle_ctr;
+
+ pendingUnlinks = lappend(pendingUnlinks, entry);
+
+ MemoryContextSwitchTo(oldcxt);
+ }
else
{
/* Normal case: enter a request to fsync this segment */
- PendingOperationTag key;
+ MemoryContext oldcxt = MemoryContextSwitchTo(pendingOpsCxt);
PendingOperationEntry *entry;
bool found;
- /* ensure any pad bytes in the hash key are zeroed */
- MemSet(&key, 0, sizeof(key));
- key.rnode = rnode;
- key.segno = segno;
-
entry = (PendingOperationEntry *) hash_search(pendingOpsTable,
- &key,
+ &rnode,
HASH_ENTER,
&found);
- if (!found) /* new entry, so initialize it */
- entry->failures = 0;
+ /* if new entry, initialize it */
+ if (!found)
+ {
+ entry->cycle_ctr = mdsync_cycle_ctr;
+ MemSet(entry->requests, 0, sizeof(entry->requests));
+ MemSet(entry->canceled, 0, sizeof(entry->canceled));
+ }
+
+ /*
+ * NB: it's intentional that we don't change cycle_ctr if the entry
+ * already exists. The cycle_ctr must represent the oldest fsync
+ * request that could be in the entry.
+ */
+
+ entry->requests[forknum] = bms_add_member(entry->requests[forknum],
+ (int) segno);
+
+ MemoryContextSwitchTo(oldcxt);
}
}
/*
- * ForgetRelationFsyncRequests -- ensure any fsyncs for a rel are forgotten
+ * ForgetRelationFsyncRequests -- forget any fsyncs for a relation fork
+ *
+ * forknum == InvalidForkNumber means all forks, although this code doesn't
+ * actually know that, since it's just forwarding the request elsewhere.
*/
void
-ForgetRelationFsyncRequests(RelFileNode rnode)
+ForgetRelationFsyncRequests(RelFileNode rnode, ForkNumber forknum)
{
if (pendingOpsTable)
{
/* standalone backend or startup process: fsync state is local */
- RememberFsyncRequest(rnode, FORGET_RELATION_FSYNC);
+ RememberFsyncRequest(rnode, forknum, FORGET_RELATION_FSYNC);
}
else if (IsUnderPostmaster)
{
/*
- * Notify the bgwriter about it. If we fail to queue the revoke
+ * Notify the checkpointer about it. If we fail to queue the cancel
* message, we have to sleep and try again ... ugly, but hopefully
* won't happen often.
*
- * XXX should we CHECK_FOR_INTERRUPTS in this loop? Escaping with
- * an error would leave the no-longer-used file still present on
- * disk, which would be bad, so I'm inclined to assume that the
- * bgwriter will always empty the queue soon.
+ * XXX should we CHECK_FOR_INTERRUPTS in this loop? Escaping with an
+ * error would leave the no-longer-used file still present on disk,
+ * which would be bad, so I'm inclined to assume that the checkpointer
+ * will always empty the queue soon.
*/
- while (!ForwardFsyncRequest(rnode, FORGET_RELATION_FSYNC))
+ while (!ForwardFsyncRequest(rnode, forknum, FORGET_RELATION_FSYNC))
pg_usleep(10000L); /* 10 msec seems a good number */
+
/*
- * Note we don't wait for the bgwriter to actually absorb the
- * revoke message; see mdsync() for the implications.
+ * Note we don't wait for the checkpointer to actually absorb the
+ * cancel message; see mdsync() for the implications.
*/
}
}
/*
- * ForgetDatabaseFsyncRequests -- ensure any fsyncs for a DB are forgotten
+ * ForgetDatabaseFsyncRequests -- forget any fsyncs and unlinks for a DB
*/
void
ForgetDatabaseFsyncRequests(Oid dbid)
if (pendingOpsTable)
{
/* standalone backend or startup process: fsync state is local */
- RememberFsyncRequest(rnode, FORGET_DATABASE_FSYNC);
+ RememberFsyncRequest(rnode, InvalidForkNumber, FORGET_DATABASE_FSYNC);
}
else if (IsUnderPostmaster)
{
/* see notes in ForgetRelationFsyncRequests */
- while (!ForwardFsyncRequest(rnode, FORGET_DATABASE_FSYNC))
+ while (!ForwardFsyncRequest(rnode, InvalidForkNumber,
+ FORGET_DATABASE_FSYNC))
pg_usleep(10000L); /* 10 msec seems a good number */
}
}
-
/*
- * _fdvec_alloc() -- Make a MdfdVec object.
+ * DropRelationFiles -- drop files of all given relations
*/
-static MdfdVec *
-_fdvec_alloc(void)
+void
+DropRelationFiles(RelFileNode *delrels, int ndelrels, bool isRedo)
{
- return (MdfdVec *) MemoryContextAlloc(MdCxt, sizeof(MdfdVec));
+ SMgrRelation *srels;
+ int i;
+
+ srels = palloc(sizeof(SMgrRelation) * ndelrels);
+ for (i = 0; i < ndelrels; i++)
+ {
+ SMgrRelation srel = smgropen(delrels[i], InvalidBackendId);
+
+ if (isRedo)
+ {
+ ForkNumber fork;
+
+ for (fork = 0; fork <= MAX_FORKNUM; fork++)
+ XLogDropRelation(delrels[i], fork);
+ }
+ srels[i] = srel;
+ }
+
+ smgrdounlinkall(srels, ndelrels, isRedo);
+
+ /*
+ * Call smgrclose() in reverse order as when smgropen() is called.
+ * This trick enables remove_from_unowned_list() in smgrclose()
+ * to search the SMgrRelation from the unowned list,
+ * with O(1) performance.
+ */
+ for (i = ndelrels - 1; i >= 0; i--)
+ smgrclose(srels[i]);
+ pfree(srels);
}
-#ifndef LET_OS_MANAGE_FILESIZE
/*
- * Open the specified segment of the relation,
- * and make a MdfdVec object for it. Returns NULL on failure.
+ * _fdvec_resize() -- Resize the fork's open segments array
*/
-static MdfdVec *
-_mdfd_openseg(SMgrRelation reln, BlockNumber segno, int oflags)
+static void
+_fdvec_resize(SMgrRelation reln,
+ ForkNumber forknum,
+ int nseg)
+{
+ if (nseg == 0)
+ {
+ if (reln->md_num_open_segs[forknum] > 0)
+ {
+ pfree(reln->md_seg_fds[forknum]);
+ reln->md_seg_fds[forknum] = NULL;
+ }
+ }
+ else if (reln->md_num_open_segs[forknum] == 0)
+ {
+ reln->md_seg_fds[forknum] =
+ MemoryContextAlloc(MdCxt, sizeof(MdfdVec) * nseg);
+ }
+ else
+ {
+ /*
+ * It doesn't seem worthwhile complicating the code by having a more
+ * aggressive growth strategy here; the number of segments doesn't
+ * grow that fast, and the memory context internally will sometimes
+ * avoid doing an actual reallocation.
+ */
+ reln->md_seg_fds[forknum] =
+ repalloc(reln->md_seg_fds[forknum],
+ sizeof(MdfdVec) * nseg);
+ }
+
+ reln->md_num_open_segs[forknum] = nseg;
+}
+
+/*
+ * Return the filename for the specified segment of the relation. The
+ * returned string is palloc'd.
+ */
+static char *
+_mdfd_segpath(SMgrRelation reln, ForkNumber forknum, BlockNumber segno)
{
- MdfdVec *v;
- int fd;
char *path,
*fullpath;
- path = relpath(reln->smgr_rnode);
+ path = relpath(reln->smgr_rnode, forknum);
if (segno > 0)
{
- /* be sure we have enough space for the '.segno' */
- fullpath = (char *) palloc(strlen(path) + 12);
- sprintf(fullpath, "%s.%u", path, segno);
+ fullpath = psprintf("%s.%u", path, segno);
pfree(path);
}
else
fullpath = path;
+ return fullpath;
+}
+
+/*
+ * Open the specified segment of the relation,
+ * and make a MdfdVec object for it. Returns NULL on failure.
+ */
+static MdfdVec *
+_mdfd_openseg(SMgrRelation reln, ForkNumber forknum, BlockNumber segno,
+ int oflags)
+{
+ MdfdVec *v;
+ int fd;
+ char *fullpath;
+
+ fullpath = _mdfd_segpath(reln, forknum, segno);
+
/* open the file */
- fd = PathNameOpenFile(fullpath, O_RDWR | PG_BINARY | oflags, 0600);
+ fd = PathNameOpenFile(fullpath, O_RDWR | PG_BINARY | oflags);
pfree(fullpath);
if (fd < 0)
return NULL;
- /* allocate an mdfdvec entry for it */
- v = _fdvec_alloc();
+ if (segno <= reln->md_num_open_segs[forknum])
+ _fdvec_resize(reln, forknum, segno + 1);
/* fill the entry */
+ v = &reln->md_seg_fds[forknum][segno];
v->mdfd_vfd = fd;
v->mdfd_segno = segno;
- v->mdfd_chain = NULL;
- Assert(_mdnblocks(reln, v) <= ((BlockNumber) RELSEG_SIZE));
+
+ Assert(_mdnblocks(reln, forknum, v) <= ((BlockNumber) RELSEG_SIZE));
/* all done */
return v;
}
-#endif /* LET_OS_MANAGE_FILESIZE */
/*
* _mdfd_getseg() -- Find the segment of the relation holding the
* specified block.
*
* If the segment doesn't exist, we ereport, return NULL, or create the
- * segment, according to "behavior". Note: isTemp need only be correct
- * in the EXTENSION_CREATE case.
+ * segment, according to "behavior". Note: skipFsync is only used in the
+ * EXTENSION_CREATE case.
*/
static MdfdVec *
-_mdfd_getseg(SMgrRelation reln, BlockNumber blkno, bool isTemp,
- ExtensionBehavior behavior)
+_mdfd_getseg(SMgrRelation reln, ForkNumber forknum, BlockNumber blkno,
+ bool skipFsync, int behavior)
{
- MdfdVec *v = mdopen(reln, behavior);
-
-#ifndef LET_OS_MANAGE_FILESIZE
+ MdfdVec *v;
BlockNumber targetseg;
BlockNumber nextsegno;
- if (!v)
- return NULL; /* only possible if EXTENSION_RETURN_NULL */
+ /* some way to handle non-existent segments needs to be specified */
+ Assert(behavior &
+ (EXTENSION_FAIL | EXTENSION_CREATE | EXTENSION_RETURN_NULL));
targetseg = blkno / ((BlockNumber) RELSEG_SIZE);
- for (nextsegno = 1; nextsegno <= targetseg; nextsegno++)
+
+ /* if an existing and opened segment, we're done */
+ if (targetseg < reln->md_num_open_segs[forknum])
+ {
+ v = &reln->md_seg_fds[forknum][targetseg];
+ return v;
+ }
+
+ /*
+ * The target segment is not yet open. Iterate over all the segments
+ * between the last opened and the target segment. This way missing
+ * segments either raise an error, or get created (according to
+ * 'behavior'). Start with either the last opened, or the first segment if
+ * none was opened before.
+ */
+ if (reln->md_num_open_segs[forknum] > 0)
+ v = &reln->md_seg_fds[forknum][reln->md_num_open_segs[forknum] - 1];
+ else
{
+ v = mdopen(reln, forknum, behavior);
+ if (!v)
+ return NULL; /* if behavior & EXTENSION_RETURN_NULL */
+ }
+
+ for (nextsegno = reln->md_num_open_segs[forknum];
+ nextsegno <= targetseg; nextsegno++)
+ {
+ BlockNumber nblocks = _mdnblocks(reln, forknum, v);
+ int flags = 0;
+
Assert(nextsegno == v->mdfd_segno + 1);
- if (v->mdfd_chain == NULL)
+ if (nblocks > ((BlockNumber) RELSEG_SIZE))
+ elog(FATAL, "segment too big");
+
+ if ((behavior & EXTENSION_CREATE) ||
+ (InRecovery && (behavior & EXTENSION_CREATE_RECOVERY)))
{
/*
- * Normally we will create new segments only if authorized by
- * the caller (i.e., we are doing mdextend()). But when doing
- * WAL recovery, create segments anyway; this allows cases such as
+ * Normally we will create new segments only if authorized by the
+ * caller (i.e., we are doing mdextend()). But when doing WAL
+ * recovery, create segments anyway; this allows cases such as
* replaying WAL data that has a write into a high-numbered
- * segment of a relation that was later deleted. We want to go
+ * segment of a relation that was later deleted. We want to go
* ahead and create the segments so we can finish out the replay.
+ * However if the caller has specified
+ * EXTENSION_REALLY_RETURN_NULL, then extension is not desired
+ * even in recovery; we won't reach this point in that case.
*
- * We have to maintain the invariant that segments before the
- * last active segment are of size RELSEG_SIZE; therefore, pad
- * them out with zeroes if needed. (This only matters if caller
- * is extending the relation discontiguously, but that can happen
- * in hash indexes.)
+ * We have to maintain the invariant that segments before the last
+ * active segment are of size RELSEG_SIZE; therefore, if
+ * extending, pad them out with zeroes if needed. (This only
+ * matters if in recovery, or if the caller is extending the
+ * relation discontiguously, but that can happen in hash indexes.)
*/
- if (behavior == EXTENSION_CREATE || InRecovery)
+ if (nblocks < ((BlockNumber) RELSEG_SIZE))
{
- if (_mdnblocks(reln, v) < RELSEG_SIZE)
- {
- char *zerobuf = palloc0(BLCKSZ);
+ char *zerobuf = palloc0(BLCKSZ);
- mdextend(reln, nextsegno * ((BlockNumber) RELSEG_SIZE) - 1,
- zerobuf, isTemp);
- pfree(zerobuf);
- }
- v->mdfd_chain = _mdfd_openseg(reln, nextsegno, O_CREAT);
+ mdextend(reln, forknum,
+ nextsegno * ((BlockNumber) RELSEG_SIZE) - 1,
+ zerobuf, skipFsync);
+ pfree(zerobuf);
}
- else
- {
- /* We won't create segment if not existent */
- v->mdfd_chain = _mdfd_openseg(reln, nextsegno, 0);
- }
- if (v->mdfd_chain == NULL)
+ flags = O_CREAT;
+ }
+ else if (!(behavior & EXTENSION_DONT_CHECK_SIZE) &&
+ nblocks < ((BlockNumber) RELSEG_SIZE))
+ {
+ /*
+ * When not extending (or explicitly including truncated
+ * segments), only open the next segment if the current one is
+ * exactly RELSEG_SIZE. If not (this branch), either return NULL
+ * or fail.
+ */
+ if (behavior & EXTENSION_RETURN_NULL)
{
- if (behavior == EXTENSION_RETURN_NULL &&
- FILE_POSSIBLY_DELETED(errno))
- return NULL;
- ereport(ERROR,
- (errcode_for_file_access(),
- errmsg("could not open segment %u of relation %u/%u/%u (target block %u): %m",
- nextsegno,
- reln->smgr_rnode.spcNode,
- reln->smgr_rnode.dbNode,
- reln->smgr_rnode.relNode,
- blkno)));
+ /*
+ * Some callers discern between reasons for _mdfd_getseg()
+ * returning NULL based on errno. As there's no failing
+ * syscall involved in this case, explicitly set errno to
+ * ENOENT, as that seems the closest interpretation.
+ */
+ errno = ENOENT;
+ return NULL;
}
+
+ ereport(ERROR,
+ (errcode_for_file_access(),
+ errmsg("could not open file \"%s\" (target block %u): previous segment is only %u blocks",
+ _mdfd_segpath(reln, forknum, nextsegno),
+ blkno, nblocks)));
+ }
+
+ v = _mdfd_openseg(reln, forknum, nextsegno, flags);
+
+ if (v == NULL)
+ {
+ if ((behavior & EXTENSION_RETURN_NULL) &&
+ FILE_POSSIBLY_DELETED(errno))
+ return NULL;
+ ereport(ERROR,
+ (errcode_for_file_access(),
+ errmsg("could not open file \"%s\" (target block %u): %m",
+ _mdfd_segpath(reln, forknum, nextsegno),
+ blkno)));
}
- v = v->mdfd_chain;
}
-#endif
return v;
}
* Get number of blocks present in a single disk file
*/
static BlockNumber
-_mdnblocks(SMgrRelation reln, MdfdVec *seg)
+_mdnblocks(SMgrRelation reln, ForkNumber forknum, MdfdVec *seg)
{
- long len;
+ off_t len;
- len = FileSeek(seg->mdfd_vfd, 0L, SEEK_END);
+ len = FileSize(seg->mdfd_vfd);
if (len < 0)
ereport(ERROR,
(errcode_for_file_access(),
- errmsg("could not seek to end of segment %u of relation %u/%u/%u: %m",
- seg->mdfd_segno,
- reln->smgr_rnode.spcNode,
- reln->smgr_rnode.dbNode,
- reln->smgr_rnode.relNode)));
+ errmsg("could not seek to end of file \"%s\": %m",
+ FilePathName(seg->mdfd_vfd))));
/* note that this calculation will ignore any partial block at EOF */
return (BlockNumber) (len / BLCKSZ);
}
projects / postgresql / blobdiff