slot.h File Reference

#include "access/xlog.h"
#include "access/xlogreader.h"
#include "storage/condition_variable.h"
#include "storage/lwlock.h"
#include "storage/shmem.h"
#include "storage/spin.h"
#include "replication/walreceiver.h"

Include dependency graph for slot.h:

This graph shows which files directly or indirectly include this file:

Go to the source code of this file.

Data Structures
struct	ReplicationSlotPersistentData
struct	ReplicationSlot
struct	ReplicationSlotCtlData

Macros
#define	SlotIsPhysical(slot)   ((slot)->data.database == InvalidOid)
#define	SlotIsLogical(slot)   ((slot)->data.database != InvalidOid)

Typedefs
typedef enum ReplicationSlotPersistency	ReplicationSlotPersistency
typedef struct ReplicationSlotPersistentData	ReplicationSlotPersistentData
typedef struct ReplicationSlot	ReplicationSlot
typedef struct ReplicationSlotCtlData	ReplicationSlotCtlData

Enumerations
enum	ReplicationSlotPersistency { RS_PERSISTENT , RS_EPHEMERAL , RS_TEMPORARY }

Functions
Size	ReplicationSlotsShmemSize (void)
void	ReplicationSlotsShmemInit (void)
void	ReplicationSlotCreate (const char *name, bool db_specific, ReplicationSlotPersistency persistency, bool two_phase)
void	ReplicationSlotPersist (void)
void	ReplicationSlotDrop (const char *name, bool nowait)
void	ReplicationSlotAcquire (const char *name, bool nowait)
void	ReplicationSlotRelease (void)
void	ReplicationSlotCleanup (void)
void	ReplicationSlotSave (void)
void	ReplicationSlotMarkDirty (void)
void	ReplicationSlotInitialize (void)
bool	ReplicationSlotValidateName (const char *name, int elevel)
void	ReplicationSlotReserveWal (void)
void	ReplicationSlotsComputeRequiredXmin (bool already_locked)
void	ReplicationSlotsComputeRequiredLSN (void)
XLogRecPtr	ReplicationSlotsComputeLogicalRestartLSN (void)
bool	ReplicationSlotsCountDBSlots (Oid dboid, int *nslots, int *nactive)
void	ReplicationSlotsDropDBSlots (Oid dboid)
bool	InvalidateObsoleteReplicationSlots (XLogSegNo oldestSegno)
ReplicationSlot *	SearchNamedReplicationSlot (const char *name, bool need_lock)
int	ReplicationSlotIndex (ReplicationSlot *slot)
bool	ReplicationSlotName (int index, Name name)
void	ReplicationSlotNameForTablesync (Oid suboid, Oid relid, char *syncslotname, Size szslot)
void	ReplicationSlotDropAtPubNode (WalReceiverConn *wrconn, char *slotname, bool missing_ok)
void	StartupReplicationSlots (void)
void	CheckPointReplicationSlots (void)
void	CheckSlotRequirements (void)
void	CheckSlotPermissions (void)

Variables
PGDLLIMPORT ReplicationSlotCtlData *	ReplicationSlotCtl
PGDLLIMPORT ReplicationSlot *	MyReplicationSlot
PGDLLIMPORT int	max_replication_slots

Macro Definition Documentation

SlotIsLogical

#define SlotIsLogical

(

slot

)

((slot)->data.database != InvalidOid)

Definition at line 169 of file slot.h.

SlotIsPhysical

#define SlotIsPhysical

(

slot

)

((slot)->data.database == InvalidOid)

Definition at line 168 of file slot.h.

Typedef Documentation

ReplicationSlot

typedef struct ReplicationSlot ReplicationSlot

ReplicationSlotCtlData

typedef struct ReplicationSlotCtlData ReplicationSlotCtlData

ReplicationSlotPersistency

typedef enum ReplicationSlotPersistency ReplicationSlotPersistency

ReplicationSlotPersistentData

typedef struct ReplicationSlotPersistentData ReplicationSlotPersistentData

Enumeration Type Documentation

ReplicationSlotPersistency

enum ReplicationSlotPersistency

Enumerator
RS_PERSISTENT
RS_EPHEMERAL
RS_TEMPORARY

Definition at line 33 of file slot.h.

{
    RS_PERSISTENT,
    RS_EPHEMERAL,
    RS_TEMPORARY
} ReplicationSlotPersistency;

Function Documentation

CheckPointReplicationSlots()

void CheckPointReplicationSlots

(

void

)

Definition at line 1442 of file slot.c.

{
    int         i;
 
    elog(DEBUG1, "performing replication slot checkpoint");
 
    /*
     * Prevent any slot from being created/dropped while we're active. As we
     * explicitly do *not* want to block iterating over replication_slots or
     * acquiring a slot we cannot take the control lock - but that's OK,
     * because holding ReplicationSlotAllocationLock is strictly stronger, and
     * enough to guarantee that nobody can change the in_use bits on us.
     */
    LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED);
 
    for (i = 0; i < max_replication_slots; i++)
    {
        ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i];
        char        path[MAXPGPATH];
 
        if (!s->in_use)
            continue;
 
        /* save the slot to disk, locking is handled in SaveSlotToPath() */
        sprintf(path, "pg_replslot/%s", NameStr(s->data.name));
        SaveSlotToPath(s, path, LOG);
    }
    LWLockRelease(ReplicationSlotAllocationLock);
}

References ReplicationSlot::data, DEBUG1, elog(), i, ReplicationSlot::in_use, LOG, LW_SHARED, LWLockAcquire(), LWLockRelease(), max_replication_slots, MAXPGPATH, ReplicationSlotPersistentData::name, NameStr, ReplicationSlotCtlData::replication_slots, ReplicationSlotCtl, SaveSlotToPath(), and sprintf.

Referenced by CheckPointGuts().

CheckSlotPermissions()

void CheckSlotPermissions

(

void

)

Definition at line 1141 of file slot.c.

{
    if (!superuser() && !has_rolreplication(GetUserId()))
        ereport(ERROR,
                (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                 errmsg("must be superuser or replication role to use replication slots")));
}

References ereport, errcode(), errmsg(), ERROR, GetUserId(), has_rolreplication(), and superuser().

Referenced by copy_replication_slot(), pg_create_logical_replication_slot(), pg_create_physical_replication_slot(), pg_drop_replication_slot(), pg_logical_slot_get_changes_guts(), and pg_replication_slot_advance().

CheckSlotRequirements()

void CheckSlotRequirements

(

void

)

Definition at line 1119 of file slot.c.

{
    /*
     * NB: Adding a new requirement likely means that RestoreSlotFromDisk()
     * needs the same check.
     */
 
    if (max_replication_slots == 0)
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("replication slots can only be used if max_replication_slots > 0")));
 
    if (wal_level < WAL_LEVEL_REPLICA)
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("replication slots can only be used if wal_level >= replica")));
}

References ereport, errcode(), errmsg(), ERROR, max_replication_slots, wal_level, and WAL_LEVEL_REPLICA.

Referenced by CheckLogicalDecodingRequirements(), copy_replication_slot(), pg_create_physical_replication_slot(), and pg_drop_replication_slot().

InvalidateObsoleteReplicationSlots()

bool InvalidateObsoleteReplicationSlots

(

XLogSegNo

oldestSegno

)

Definition at line 1399 of file slot.c.

{
    XLogRecPtr  oldestLSN;
    bool        invalidated = false;
 
    XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN);
 
restart:
    LWLockAcquire(ReplicationSlotControlLock, LW_SHARED);
    for (int i = 0; i < max_replication_slots; i++)
    {
        ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i];
 
        if (!s->in_use)
            continue;
 
        if (InvalidatePossiblyObsoleteSlot(s, oldestLSN, &invalidated))
        {
            /* if the lock was released, start from scratch */
            goto restart;
        }
    }
    LWLockRelease(ReplicationSlotControlLock);
 
    /*
     * If any slots have been invalidated, recalculate the resource limits.
     */
    if (invalidated)
    {
        ReplicationSlotsComputeRequiredXmin(false);
        ReplicationSlotsComputeRequiredLSN();
    }
 
    return invalidated;
}

References i, ReplicationSlot::in_use, InvalidatePossiblyObsoleteSlot(), LW_SHARED, LWLockAcquire(), LWLockRelease(), max_replication_slots, ReplicationSlotCtlData::replication_slots, ReplicationSlotCtl, ReplicationSlotsComputeRequiredLSN(), ReplicationSlotsComputeRequiredXmin(), wal_segment_size, and XLogSegNoOffsetToRecPtr.

Referenced by CreateCheckPoint(), and CreateRestartPoint().

ReplicationSlotAcquire()

void ReplicationSlotAcquire	(	const char *	name,
		bool	nowait
	)

Definition at line 450 of file slot.c.

{
    ReplicationSlot *s;
    int         active_pid;
 
    Assert(name != NULL);
 
retry:
    Assert(MyReplicationSlot == NULL);
 
    LWLockAcquire(ReplicationSlotControlLock, LW_SHARED);
 
    /*
     * Search for the slot with the specified name if the slot to acquire is
     * not given. If the slot is not found, we either return -1 or error out.
     */
    s = SearchNamedReplicationSlot(name, false);
    if (s == NULL || !s->in_use)
    {
        LWLockRelease(ReplicationSlotControlLock);
 
        ereport(ERROR,
                (errcode(ERRCODE_UNDEFINED_OBJECT),
                 errmsg("replication slot \"%s\" does not exist",
                        name)));
    }
 
    /*
     * This is the slot we want; check if it's active under some other
     * process.  In single user mode, we don't need this check.
     */
    if (IsUnderPostmaster)
    {
        /*
         * Get ready to sleep on the slot in case it is active.  (We may end
         * up not sleeping, but we don't want to do this while holding the
         * spinlock.)
         */
        if (!nowait)
            ConditionVariablePrepareToSleep(&s->active_cv);
 
        SpinLockAcquire(&s->mutex);
        if (s->active_pid == 0)
            s->active_pid = MyProcPid;
        active_pid = s->active_pid;
        SpinLockRelease(&s->mutex);
    }
    else
        active_pid = MyProcPid;
    LWLockRelease(ReplicationSlotControlLock);
 
    /*
     * If we found the slot but it's already active in another process, we
     * wait until the owning process signals us that it's been released, or
     * error out.
     */
    if (active_pid != MyProcPid)
    {
        if (!nowait)
        {
            /* Wait here until we get signaled, and then restart */
            ConditionVariableSleep(&s->active_cv,
                                   WAIT_EVENT_REPLICATION_SLOT_DROP);
            ConditionVariableCancelSleep();
            goto retry;
        }
 
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_IN_USE),
                 errmsg("replication slot \"%s\" is active for PID %d",
                        NameStr(s->data.name), active_pid)));
    }
    else if (!nowait)
        ConditionVariableCancelSleep(); /* no sleep needed after all */
 
    /* Let everybody know we've modified this slot */
    ConditionVariableBroadcast(&s->active_cv);
 
    /* We made this slot active, so it's ours now. */
    MyReplicationSlot = s;
 
    /*
     * The call to pgstat_acquire_replslot() protects against stats for a
     * different slot, from before a restart or such, being present during
     * pgstat_report_replslot().
     */
    if (SlotIsLogical(s))
        pgstat_acquire_replslot(s);
}

References ReplicationSlot::active_cv, ReplicationSlot::active_pid, Assert(), ConditionVariableBroadcast(), ConditionVariableCancelSleep(), ConditionVariablePrepareToSleep(), ConditionVariableSleep(), ReplicationSlot::data, ereport, errcode(), errmsg(), ERROR, ReplicationSlot::in_use, IsUnderPostmaster, LW_SHARED, LWLockAcquire(), LWLockRelease(), ReplicationSlot::mutex, MyProcPid, MyReplicationSlot, name, ReplicationSlotPersistentData::name, NameStr, pgstat_acquire_replslot(), SearchNamedReplicationSlot(), SlotIsLogical, SpinLockAcquire, SpinLockRelease, and WAIT_EVENT_REPLICATION_SLOT_DROP.

Referenced by pg_logical_slot_get_changes_guts(), pg_replication_slot_advance(), ReplicationSlotDrop(), StartLogicalReplication(), and StartReplication().

ReplicationSlotCleanup()

void ReplicationSlotCleanup

(

void

)

Definition at line 603 of file slot.c.

{
    int         i;
 
    Assert(MyReplicationSlot == NULL);
 
restart:
    LWLockAcquire(ReplicationSlotControlLock, LW_SHARED);
    for (i = 0; i < max_replication_slots; i++)
    {
        ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i];
 
        if (!s->in_use)
            continue;
 
        SpinLockAcquire(&s->mutex);
        if (s->active_pid == MyProcPid)
        {
            Assert(s->data.persistency == RS_TEMPORARY);
            SpinLockRelease(&s->mutex);
            LWLockRelease(ReplicationSlotControlLock);  /* avoid deadlock */
 
            ReplicationSlotDropPtr(s);
 
            ConditionVariableBroadcast(&s->active_cv);
            goto restart;
        }
        else
            SpinLockRelease(&s->mutex);
    }
 
    LWLockRelease(ReplicationSlotControlLock);
}

References ReplicationSlot::active_cv, ReplicationSlot::active_pid, Assert(), ConditionVariableBroadcast(), ReplicationSlot::data, i, ReplicationSlot::in_use, LW_SHARED, LWLockAcquire(), LWLockRelease(), max_replication_slots, ReplicationSlot::mutex, MyProcPid, MyReplicationSlot, ReplicationSlotPersistentData::persistency, ReplicationSlotCtlData::replication_slots, ReplicationSlotCtl, ReplicationSlotDropPtr(), RS_TEMPORARY, SpinLockAcquire, and SpinLockRelease.

Referenced by PostgresMain(), ReplicationSlotShmemExit(), and WalSndErrorCleanup().

ReplicationSlotCreate()

void ReplicationSlotCreate	(	const char *	name,
		bool	db_specific,
		ReplicationSlotPersistency	persistency,
		bool	two_phase
	)

Definition at line 252 of file slot.c.

{
    ReplicationSlot *slot = NULL;
    int         i;
 
    Assert(MyReplicationSlot == NULL);
 
    ReplicationSlotValidateName(name, ERROR);
 
    /*
     * If some other backend ran this code concurrently with us, we'd likely
     * both allocate the same slot, and that would be bad.  We'd also be at
     * risk of missing a name collision.  Also, we don't want to try to create
     * a new slot while somebody's busy cleaning up an old one, because we
     * might both be monkeying with the same directory.
     */
    LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE);
 
    /*
     * Check for name collision, and identify an allocatable slot.  We need to
     * hold ReplicationSlotControlLock in shared mode for this, so that nobody
     * else can change the in_use flags while we're looking at them.
     */
    LWLockAcquire(ReplicationSlotControlLock, LW_SHARED);
    for (i = 0; i < max_replication_slots; i++)
    {
        ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i];
 
        if (s->in_use && strcmp(name, NameStr(s->data.name)) == 0)
            ereport(ERROR,
                    (errcode(ERRCODE_DUPLICATE_OBJECT),
                     errmsg("replication slot \"%s\" already exists", name)));
        if (!s->in_use && slot == NULL)
            slot = s;
    }
    LWLockRelease(ReplicationSlotControlLock);
 
    /* If all slots are in use, we're out of luck. */
    if (slot == NULL)
        ereport(ERROR,
                (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED),
                 errmsg("all replication slots are in use"),
                 errhint("Free one or increase max_replication_slots.")));
 
    /*
     * Since this slot is not in use, nobody should be looking at any part of
     * it other than the in_use field unless they're trying to allocate it.
     * And since we hold ReplicationSlotAllocationLock, nobody except us can
     * be doing that.  So it's safe to initialize the slot.
     */
    Assert(!slot->in_use);
    Assert(slot->active_pid == 0);
 
    /* first initialize persistent data */
    memset(&slot->data, 0, sizeof(ReplicationSlotPersistentData));
    namestrcpy(&slot->data.name, name);
    slot->data.database = db_specific ? MyDatabaseId : InvalidOid;
    slot->data.persistency = persistency;
    slot->data.two_phase = two_phase;
    slot->data.two_phase_at = InvalidXLogRecPtr;
 
    /* and then data only present in shared memory */
    slot->just_dirtied = false;
    slot->dirty = false;
    slot->effective_xmin = InvalidTransactionId;
    slot->effective_catalog_xmin = InvalidTransactionId;
    slot->candidate_catalog_xmin = InvalidTransactionId;
    slot->candidate_xmin_lsn = InvalidXLogRecPtr;
    slot->candidate_restart_valid = InvalidXLogRecPtr;
    slot->candidate_restart_lsn = InvalidXLogRecPtr;
 
    /*
     * Create the slot on disk.  We haven't actually marked the slot allocated
     * yet, so no special cleanup is required if this errors out.
     */
    CreateSlotOnDisk(slot);
 
    /*
     * We need to briefly prevent any other backend from iterating over the
     * slots while we flip the in_use flag. We also need to set the active
     * flag while holding the ControlLock as otherwise a concurrent
     * ReplicationSlotAcquire() could acquire the slot as well.
     */
    LWLockAcquire(ReplicationSlotControlLock, LW_EXCLUSIVE);
 
    slot->in_use = true;
 
    /* We can now mark the slot active, and that makes it our slot. */
    SpinLockAcquire(&slot->mutex);
    Assert(slot->active_pid == 0);
    slot->active_pid = MyProcPid;
    SpinLockRelease(&slot->mutex);
    MyReplicationSlot = slot;
 
    LWLockRelease(ReplicationSlotControlLock);
 
    /*
     * Create statistics entry for the new logical slot. We don't collect any
     * stats for physical slots, so no need to create an entry for the same.
     * See ReplicationSlotDropPtr for why we need to do this before releasing
     * ReplicationSlotAllocationLock.
     */
    if (SlotIsLogical(slot))
        pgstat_create_replslot(slot);
 
    /*
     * Now that the slot has been marked as in_use and active, it's safe to
     * let somebody else try to allocate a slot.
     */
    LWLockRelease(ReplicationSlotAllocationLock);
 
    /* Let everybody know we've modified this slot */
    ConditionVariableBroadcast(&slot->active_cv);
}

References ReplicationSlot::active_cv, ReplicationSlot::active_pid, Assert(), ReplicationSlot::candidate_catalog_xmin, ReplicationSlot::candidate_restart_lsn, ReplicationSlot::candidate_restart_valid, ReplicationSlot::candidate_xmin_lsn, ConditionVariableBroadcast(), CreateSlotOnDisk(), ReplicationSlot::data, ReplicationSlotPersistentData::database, ReplicationSlot::dirty, ReplicationSlot::effective_catalog_xmin, ReplicationSlot::effective_xmin, ereport, errcode(), ERRCODE_DUPLICATE_OBJECT, errhint(), errmsg(), ERROR, i, ReplicationSlot::in_use, InvalidOid, InvalidTransactionId, InvalidXLogRecPtr, ReplicationSlot::just_dirtied, LW_EXCLUSIVE, LW_SHARED, LWLockAcquire(), LWLockRelease(), max_replication_slots, ReplicationSlot::mutex, MyDatabaseId, MyProcPid, MyReplicationSlot, name, ReplicationSlotPersistentData::name, NameStr, namestrcpy(), ReplicationSlotPersistentData::persistency, pgstat_create_replslot(), ReplicationSlotCtlData::replication_slots, ReplicationSlotCtl, ReplicationSlotValidateName(), SlotIsLogical, SpinLockAcquire, SpinLockRelease, two_phase, ReplicationSlotPersistentData::two_phase, and ReplicationSlotPersistentData::two_phase_at.

Referenced by create_logical_replication_slot(), create_physical_replication_slot(), and CreateReplicationSlot().

ReplicationSlotDrop()

void ReplicationSlotDrop	(	const char *	name,
		bool	nowait
	)

Definition at line 641 of file slot.c.

{
    Assert(MyReplicationSlot == NULL);
 
    ReplicationSlotAcquire(name, nowait);
 
    ReplicationSlotDropAcquired();
}

References Assert(), MyReplicationSlot, name, ReplicationSlotAcquire(), and ReplicationSlotDropAcquired().

Referenced by DropReplicationSlot(), and pg_drop_replication_slot().

ReplicationSlotDropAtPubNode()

void ReplicationSlotDropAtPubNode	(	WalReceiverConn *	wrconn,
		char *	slotname,
		bool	missing_ok
	)

Definition at line 1662 of file subscriptioncmds.c.

{
    StringInfoData cmd;
 
    Assert(wrconn);
 
    load_file("libpqwalreceiver", false);
 
    initStringInfo(&cmd);
    appendStringInfo(&cmd, "DROP_REPLICATION_SLOT %s WAIT", quote_identifier(slotname));
 
    PG_TRY();
    {
        WalRcvExecResult *res;
 
        res = walrcv_exec(wrconn, cmd.data, 0, NULL);
 
        if (res->status == WALRCV_OK_COMMAND)
        {
            /* NOTICE. Success. */
            ereport(NOTICE,
                    (errmsg("dropped replication slot \"%s\" on publisher",
                            slotname)));
        }
        else if (res->status == WALRCV_ERROR &&
                 missing_ok &&
                 res->sqlstate == ERRCODE_UNDEFINED_OBJECT)
        {
            /* LOG. Error, but missing_ok = true. */
            ereport(LOG,
                    (errmsg("could not drop replication slot \"%s\" on publisher: %s",
                            slotname, res->err)));
        }
        else
        {
            /* ERROR. */
            ereport(ERROR,
                    (errcode(ERRCODE_CONNECTION_FAILURE),
                     errmsg("could not drop replication slot \"%s\" on publisher: %s",
                            slotname, res->err)));
        }
 
        walrcv_clear_result(res);
    }
    PG_FINALLY();
    {
        pfree(cmd.data);
    }
    PG_END_TRY();
}

References appendStringInfo(), Assert(), StringInfoData::data, ereport, errcode(), errmsg(), ERROR, initStringInfo(), load_file(), LOG, NOTICE, pfree(), PG_END_TRY, PG_FINALLY, PG_TRY, quote_identifier(), res, walrcv_clear_result(), WALRCV_ERROR, walrcv_exec, WALRCV_OK_COMMAND, and wrconn.

Referenced by AlterSubscription_refresh(), DropSubscription(), LogicalRepSyncTableStart(), and process_syncing_tables_for_sync().

ReplicationSlotIndex()

int ReplicationSlotIndex

(

ReplicationSlot *

slot

)

Definition at line 407 of file slot.c.

{
    Assert(slot >= ReplicationSlotCtl->replication_slots &&
           slot < ReplicationSlotCtl->replication_slots + max_replication_slots);
 
    return slot - ReplicationSlotCtl->replication_slots;
}

References Assert(), max_replication_slots, ReplicationSlotCtlData::replication_slots, and ReplicationSlotCtl.

Referenced by get_replslot_index(), pgstat_acquire_replslot(), pgstat_create_replslot(), pgstat_drop_replslot(), pgstat_report_replslot(), and pgstat_reset_replslot().

ReplicationSlotInitialize()

void ReplicationSlotInitialize

(

void

)

Definition at line 170 of file slot.c.

{
    before_shmem_exit(ReplicationSlotShmemExit, 0);
}

References before_shmem_exit(), and ReplicationSlotShmemExit().

Referenced by BaseInit().

ReplicationSlotMarkDirty()

void ReplicationSlotMarkDirty

(

void

)

Definition at line 796 of file slot.c.

{
    ReplicationSlot *slot = MyReplicationSlot;
 
    Assert(MyReplicationSlot != NULL);
 
    SpinLockAcquire(&slot->mutex);
    MyReplicationSlot->just_dirtied = true;
    MyReplicationSlot->dirty = true;
    SpinLockRelease(&slot->mutex);
}

References Assert(), ReplicationSlot::dirty, ReplicationSlot::just_dirtied, ReplicationSlot::mutex, MyReplicationSlot, SpinLockAcquire, and SpinLockRelease.

Referenced by copy_replication_slot(), create_physical_replication_slot(), CreateDecodingContext(), CreateInitDecodingContext(), CreateReplicationSlot(), InvalidatePossiblyObsoleteSlot(), LogicalConfirmReceivedLocation(), pg_logical_replication_slot_advance(), pg_logical_slot_get_changes_guts(), pg_physical_replication_slot_advance(), PhysicalConfirmReceivedLocation(), PhysicalReplicationSlotNewXmin(), and ReplicationSlotPersist().

ReplicationSlotName()

bool ReplicationSlotName	(	int	index,
		Name	name
	)

Definition at line 423 of file slot.c.

{
    ReplicationSlot *slot;
    bool        found;
 
    slot = &ReplicationSlotCtl->replication_slots[index];
 
    /*
     * Ensure that the slot cannot be dropped while we copy the name. Don't
     * need the spinlock as the name of an existing slot cannot change.
     */
    LWLockAcquire(ReplicationSlotControlLock, LW_SHARED);
    found = slot->in_use;
    if (slot->in_use)
        namestrcpy(name, NameStr(slot->data.name));
    LWLockRelease(ReplicationSlotControlLock);
 
    return found;
}

References ReplicationSlot::data, ReplicationSlot::in_use, LW_SHARED, LWLockAcquire(), LWLockRelease(), name, ReplicationSlotPersistentData::name, NameStr, namestrcpy(), ReplicationSlotCtlData::replication_slots, and ReplicationSlotCtl.

Referenced by pgstat_replslot_to_serialized_name_cb().

ReplicationSlotNameForTablesync()

void ReplicationSlotNameForTablesync	(	Oid	suboid,
		Oid	relid,
		char *	syncslotname,
		Size	szslot
	)

Definition at line 1213 of file tablesync.c.

{
    snprintf(syncslotname, szslot, "pg_%u_sync_%u_" UINT64_FORMAT, suboid,
             relid, GetSystemIdentifier());
}

References GetSystemIdentifier(), snprintf, and UINT64_FORMAT.

Referenced by AlterSubscription_refresh(), DropSubscription(), LogicalRepSyncTableStart(), process_syncing_tables_for_sync(), and ReportSlotConnectionError().

ReplicationSlotPersist()

void ReplicationSlotPersist

(

void

)

Definition at line 813 of file slot.c.

{
    ReplicationSlot *slot = MyReplicationSlot;
 
    Assert(slot != NULL);
    Assert(slot->data.persistency != RS_PERSISTENT);
 
    SpinLockAcquire(&slot->mutex);
    slot->data.persistency = RS_PERSISTENT;
    SpinLockRelease(&slot->mutex);
 
    ReplicationSlotMarkDirty();
    ReplicationSlotSave();
}

References Assert(), ReplicationSlot::data, ReplicationSlot::mutex, MyReplicationSlot, ReplicationSlotPersistentData::persistency, ReplicationSlotMarkDirty(), ReplicationSlotSave(), RS_PERSISTENT, SpinLockAcquire, and SpinLockRelease.

Referenced by copy_replication_slot(), CreateReplicationSlot(), and pg_create_logical_replication_slot().

ReplicationSlotRelease()

void ReplicationSlotRelease

(

void

)

Definition at line 547 of file slot.c.

{
    ReplicationSlot *slot = MyReplicationSlot;
 
    Assert(slot != NULL && slot->active_pid != 0);
 
    if (slot->data.persistency == RS_EPHEMERAL)
    {
        /*
         * Delete the slot. There is no !PANIC case where this is allowed to
         * fail, all that may happen is an incomplete cleanup of the on-disk
         * data.
         */
        ReplicationSlotDropAcquired();
    }
 
    /*
     * If slot needed to temporarily restrain both data and catalog xmin to
     * create the catalog snapshot, remove that temporary constraint.
     * Snapshots can only be exported while the initial snapshot is still
     * acquired.
     */
    if (!TransactionIdIsValid(slot->data.xmin) &&
        TransactionIdIsValid(slot->effective_xmin))
    {
        SpinLockAcquire(&slot->mutex);
        slot->effective_xmin = InvalidTransactionId;
        SpinLockRelease(&slot->mutex);
        ReplicationSlotsComputeRequiredXmin(false);
    }
 
    if (slot->data.persistency == RS_PERSISTENT)
    {
        /*
         * Mark persistent slot inactive.  We're not freeing it, just
         * disconnecting, but wake up others that may be waiting for it.
         */
        SpinLockAcquire(&slot->mutex);
        slot->active_pid = 0;
        SpinLockRelease(&slot->mutex);
        ConditionVariableBroadcast(&slot->active_cv);
    }
 
    MyReplicationSlot = NULL;
 
    /* might not have been set when we've been a plain slot */
    LWLockAcquire(ProcArrayLock, LW_EXCLUSIVE);
    MyProc->statusFlags &= ~PROC_IN_LOGICAL_DECODING;
    ProcGlobal->statusFlags[MyProc->pgxactoff] = MyProc->statusFlags;
    LWLockRelease(ProcArrayLock);
}

References ReplicationSlot::active_cv, ReplicationSlot::active_pid, Assert(), ConditionVariableBroadcast(), ReplicationSlot::data, ReplicationSlot::effective_xmin, InvalidTransactionId, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), ReplicationSlot::mutex, MyProc, MyReplicationSlot, ReplicationSlotPersistentData::persistency, PGPROC::pgxactoff, PROC_IN_LOGICAL_DECODING, ProcGlobal, ReplicationSlotDropAcquired(), ReplicationSlotsComputeRequiredXmin(), RS_EPHEMERAL, RS_PERSISTENT, SpinLockAcquire, SpinLockRelease, PGPROC::statusFlags, PROC_HDR::statusFlags, TransactionIdIsValid, and ReplicationSlotPersistentData::xmin.

Referenced by copy_replication_slot(), CreateReplicationSlot(), InvalidatePossiblyObsoleteSlot(), pg_create_logical_replication_slot(), pg_create_physical_replication_slot(), pg_logical_slot_get_changes_guts(), pg_replication_slot_advance(), PostgresMain(), ReplicationSlotShmemExit(), StartLogicalReplication(), StartReplication(), and WalSndErrorCleanup().

ReplicationSlotReserveWal()

void ReplicationSlotReserveWal

(

void

)

Definition at line 1156 of file slot.c.

{
    ReplicationSlot *slot = MyReplicationSlot;
 
    Assert(slot != NULL);
    Assert(slot->data.restart_lsn == InvalidXLogRecPtr);
 
    /*
     * The replication slot mechanism is used to prevent removal of required
     * WAL. As there is no interlock between this routine and checkpoints, WAL
     * segments could concurrently be removed when a now stale return value of
     * ReplicationSlotsComputeRequiredLSN() is used. In the unlikely case that
     * this happens we'll just retry.
     */
    while (true)
    {
        XLogSegNo   segno;
        XLogRecPtr  restart_lsn;
 
        /*
         * For logical slots log a standby snapshot and start logical decoding
         * at exactly that position. That allows the slot to start up more
         * quickly.
         *
         * That's not needed (or indeed helpful) for physical slots as they'll
         * start replay at the last logged checkpoint anyway. Instead return
         * the location of the last redo LSN. While that slightly increases
         * the chance that we have to retry, it's where a base backup has to
         * start replay at.
         */
        if (!RecoveryInProgress() && SlotIsLogical(slot))
        {
            XLogRecPtr  flushptr;
 
            /* start at current insert position */
            restart_lsn = GetXLogInsertRecPtr();
            SpinLockAcquire(&slot->mutex);
            slot->data.restart_lsn = restart_lsn;
            SpinLockRelease(&slot->mutex);
 
            /* make sure we have enough information to start */
            flushptr = LogStandbySnapshot();
 
            /* and make sure it's fsynced to disk */
            XLogFlush(flushptr);
        }
        else
        {
            restart_lsn = GetRedoRecPtr();
            SpinLockAcquire(&slot->mutex);
            slot->data.restart_lsn = restart_lsn;
            SpinLockRelease(&slot->mutex);
        }
 
        /* prevent WAL removal as fast as possible */
        ReplicationSlotsComputeRequiredLSN();
 
        /*
         * If all required WAL is still there, great, otherwise retry. The
         * slot should prevent further removal of WAL, unless there's a
         * concurrent ReplicationSlotsComputeRequiredLSN() after we've written
         * the new restart_lsn above, so normally we should never need to loop
         * more than twice.
         */
        XLByteToSeg(slot->data.restart_lsn, segno, wal_segment_size);
        if (XLogGetLastRemovedSegno() < segno)
            break;
    }
}

References Assert(), ReplicationSlot::data, GetRedoRecPtr(), GetXLogInsertRecPtr(), InvalidXLogRecPtr, LogStandbySnapshot(), ReplicationSlot::mutex, MyReplicationSlot, RecoveryInProgress(), ReplicationSlotsComputeRequiredLSN(), ReplicationSlotPersistentData::restart_lsn, SlotIsLogical, SpinLockAcquire, SpinLockRelease, wal_segment_size, XLByteToSeg, XLogFlush(), and XLogGetLastRemovedSegno().

Referenced by create_physical_replication_slot(), CreateInitDecodingContext(), and CreateReplicationSlot().

ReplicationSlotSave()

void ReplicationSlotSave

(

void

)

Definition at line 778 of file slot.c.

{
    char        path[MAXPGPATH];
 
    Assert(MyReplicationSlot != NULL);
 
    sprintf(path, "pg_replslot/%s", NameStr(MyReplicationSlot->data.name));
    SaveSlotToPath(MyReplicationSlot, path, ERROR);
}

References Assert(), ReplicationSlot::data, ERROR, MAXPGPATH, MyReplicationSlot, ReplicationSlotPersistentData::name, NameStr, SaveSlotToPath(), and sprintf.

Referenced by copy_replication_slot(), create_physical_replication_slot(), CreateDecodingContext(), CreateInitDecodingContext(), CreateReplicationSlot(), InvalidatePossiblyObsoleteSlot(), LogicalConfirmReceivedLocation(), and ReplicationSlotPersist().

ReplicationSlotsComputeLogicalRestartLSN()

XLogRecPtr ReplicationSlotsComputeLogicalRestartLSN

(

void

)

Definition at line 935 of file slot.c.

{
    XLogRecPtr  result = InvalidXLogRecPtr;
    int         i;
 
    if (max_replication_slots <= 0)
        return InvalidXLogRecPtr;
 
    LWLockAcquire(ReplicationSlotControlLock, LW_SHARED);
 
    for (i = 0; i < max_replication_slots; i++)
    {
        ReplicationSlot *s;
        XLogRecPtr  restart_lsn;
 
        s = &ReplicationSlotCtl->replication_slots[i];
 
        /* cannot change while ReplicationSlotCtlLock is held */
        if (!s->in_use)
            continue;
 
        /* we're only interested in logical slots */
        if (!SlotIsLogical(s))
            continue;
 
        /* read once, it's ok if it increases while we're checking */
        SpinLockAcquire(&s->mutex);
        restart_lsn = s->data.restart_lsn;
        SpinLockRelease(&s->mutex);
 
        if (restart_lsn == InvalidXLogRecPtr)
            continue;
 
        if (result == InvalidXLogRecPtr ||
            restart_lsn < result)
            result = restart_lsn;
    }
 
    LWLockRelease(ReplicationSlotControlLock);
 
    return result;
}

References ReplicationSlot::data, i, ReplicationSlot::in_use, InvalidXLogRecPtr, LW_SHARED, LWLockAcquire(), LWLockRelease(), max_replication_slots, ReplicationSlot::mutex, ReplicationSlotCtlData::replication_slots, ReplicationSlotCtl, ReplicationSlotPersistentData::restart_lsn, SlotIsLogical, SpinLockAcquire, and SpinLockRelease.

Referenced by CheckPointLogicalRewriteHeap(), and CheckPointSnapBuild().

ReplicationSlotsComputeRequiredLSN()

void ReplicationSlotsComputeRequiredLSN

(

void

)

Definition at line 892 of file slot.c.

{
    int         i;
    XLogRecPtr  min_required = InvalidXLogRecPtr;
 
    Assert(ReplicationSlotCtl != NULL);
 
    LWLockAcquire(ReplicationSlotControlLock, LW_SHARED);
    for (i = 0; i < max_replication_slots; i++)
    {
        ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i];
        XLogRecPtr  restart_lsn;
 
        if (!s->in_use)
            continue;
 
        SpinLockAcquire(&s->mutex);
        restart_lsn = s->data.restart_lsn;
        SpinLockRelease(&s->mutex);
 
        if (restart_lsn != InvalidXLogRecPtr &&
            (min_required == InvalidXLogRecPtr ||
             restart_lsn < min_required))
            min_required = restart_lsn;
    }
    LWLockRelease(ReplicationSlotControlLock);
 
    XLogSetReplicationSlotMinimumLSN(min_required);
}

References Assert(), ReplicationSlot::data, i, ReplicationSlot::in_use, InvalidXLogRecPtr, LW_SHARED, LWLockAcquire(), LWLockRelease(), max_replication_slots, ReplicationSlot::mutex, ReplicationSlotCtlData::replication_slots, ReplicationSlotCtl, ReplicationSlotPersistentData::restart_lsn, SpinLockAcquire, SpinLockRelease, and XLogSetReplicationSlotMinimumLSN().

Referenced by copy_replication_slot(), InvalidateObsoleteReplicationSlots(), LogicalConfirmReceivedLocation(), pg_replication_slot_advance(), PhysicalConfirmReceivedLocation(), ReplicationSlotDropPtr(), ReplicationSlotReserveWal(), and StartupReplicationSlots().

ReplicationSlotsComputeRequiredXmin()

void ReplicationSlotsComputeRequiredXmin

(

bool

already_locked

)

Definition at line 835 of file slot.c.

{
    int         i;
    TransactionId agg_xmin = InvalidTransactionId;
    TransactionId agg_catalog_xmin = InvalidTransactionId;
 
    Assert(ReplicationSlotCtl != NULL);
 
    LWLockAcquire(ReplicationSlotControlLock, LW_SHARED);
 
    for (i = 0; i < max_replication_slots; i++)
    {
        ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i];
        TransactionId effective_xmin;
        TransactionId effective_catalog_xmin;
        bool        invalidated;
 
        if (!s->in_use)
            continue;
 
        SpinLockAcquire(&s->mutex);
        effective_xmin = s->effective_xmin;
        effective_catalog_xmin = s->effective_catalog_xmin;
        invalidated = (!XLogRecPtrIsInvalid(s->data.invalidated_at) &&
                       XLogRecPtrIsInvalid(s->data.restart_lsn));
        SpinLockRelease(&s->mutex);
 
        /* invalidated slots need not apply */
        if (invalidated)
            continue;
 
        /* check the data xmin */
        if (TransactionIdIsValid(effective_xmin) &&
            (!TransactionIdIsValid(agg_xmin) ||
             TransactionIdPrecedes(effective_xmin, agg_xmin)))
            agg_xmin = effective_xmin;
 
        /* check the catalog xmin */
        if (TransactionIdIsValid(effective_catalog_xmin) &&
            (!TransactionIdIsValid(agg_catalog_xmin) ||
             TransactionIdPrecedes(effective_catalog_xmin, agg_catalog_xmin)))
            agg_catalog_xmin = effective_catalog_xmin;
    }
 
    LWLockRelease(ReplicationSlotControlLock);
 
    ProcArraySetReplicationSlotXmin(agg_xmin, agg_catalog_xmin, already_locked);
}

References Assert(), ReplicationSlot::data, ReplicationSlot::effective_catalog_xmin, ReplicationSlot::effective_xmin, i, ReplicationSlot::in_use, ReplicationSlotPersistentData::invalidated_at, InvalidTransactionId, LW_SHARED, LWLockAcquire(), LWLockRelease(), max_replication_slots, ReplicationSlot::mutex, ProcArraySetReplicationSlotXmin(), ReplicationSlotCtlData::replication_slots, ReplicationSlotCtl, ReplicationSlotPersistentData::restart_lsn, SpinLockAcquire, SpinLockRelease, TransactionIdIsValid, TransactionIdPrecedes(), and XLogRecPtrIsInvalid.

Referenced by copy_replication_slot(), CreateInitDecodingContext(), InvalidateObsoleteReplicationSlots(), LogicalConfirmReceivedLocation(), pg_replication_slot_advance(), PhysicalReplicationSlotNewXmin(), ReplicationSlotDropPtr(), ReplicationSlotRelease(), and StartupReplicationSlots().

ReplicationSlotsCountDBSlots()

bool ReplicationSlotsCountDBSlots	(	Oid	dboid,
		int *	nslots,
		int *	nactive
	)

Definition at line 987 of file slot.c.

{
    int         i;
 
    *nslots = *nactive = 0;
 
    if (max_replication_slots <= 0)
        return false;
 
    LWLockAcquire(ReplicationSlotControlLock, LW_SHARED);
    for (i = 0; i < max_replication_slots; i++)
    {
        ReplicationSlot *s;
 
        s = &ReplicationSlotCtl->replication_slots[i];
 
        /* cannot change while ReplicationSlotCtlLock is held */
        if (!s->in_use)
            continue;
 
        /* only logical slots are database specific, skip */
        if (!SlotIsLogical(s))
            continue;
 
        /* not our database, skip */
        if (s->data.database != dboid)
            continue;
 
        /* count slots with spinlock held */
        SpinLockAcquire(&s->mutex);
        (*nslots)++;
        if (s->active_pid != 0)
            (*nactive)++;
        SpinLockRelease(&s->mutex);
    }
    LWLockRelease(ReplicationSlotControlLock);
 
    if (*nslots > 0)
        return true;
    return false;
}

References ReplicationSlot::active_pid, ReplicationSlot::data, ReplicationSlotPersistentData::database, i, ReplicationSlot::in_use, LW_SHARED, LWLockAcquire(), LWLockRelease(), max_replication_slots, ReplicationSlot::mutex, ReplicationSlotCtlData::replication_slots, ReplicationSlotCtl, SlotIsLogical, SpinLockAcquire, and SpinLockRelease.

Referenced by dropdb().

ReplicationSlotsDropDBSlots()

void ReplicationSlotsDropDBSlots

(

Oid

dboid

)

Definition at line 1043 of file slot.c.

{
    int         i;
 
    if (max_replication_slots <= 0)
        return;
 
restart:
    LWLockAcquire(ReplicationSlotControlLock, LW_SHARED);
    for (i = 0; i < max_replication_slots; i++)
    {
        ReplicationSlot *s;
        char       *slotname;
        int         active_pid;
 
        s = &ReplicationSlotCtl->replication_slots[i];
 
        /* cannot change while ReplicationSlotCtlLock is held */
        if (!s->in_use)
            continue;
 
        /* only logical slots are database specific, skip */
        if (!SlotIsLogical(s))
            continue;
 
        /* not our database, skip */
        if (s->data.database != dboid)
            continue;
 
        /* acquire slot, so ReplicationSlotDropAcquired can be reused  */
        SpinLockAcquire(&s->mutex);
        /* can't change while ReplicationSlotControlLock is held */
        slotname = NameStr(s->data.name);
        active_pid = s->active_pid;
        if (active_pid == 0)
        {
            MyReplicationSlot = s;
            s->active_pid = MyProcPid;
        }
        SpinLockRelease(&s->mutex);
 
        /*
         * Even though we hold an exclusive lock on the database object a
         * logical slot for that DB can still be active, e.g. if it's
         * concurrently being dropped by a backend connected to another DB.
         *
         * That's fairly unlikely in practice, so we'll just bail out.
         */
        if (active_pid)
            ereport(ERROR,
                    (errcode(ERRCODE_OBJECT_IN_USE),
                     errmsg("replication slot \"%s\" is active for PID %d",
                            slotname, active_pid)));
 
        /*
         * To avoid duplicating ReplicationSlotDropAcquired() and to avoid
         * holding ReplicationSlotControlLock over filesystem operations,
         * release ReplicationSlotControlLock and use
         * ReplicationSlotDropAcquired.
         *
         * As that means the set of slots could change, restart scan from the
         * beginning each time we release the lock.
         */
        LWLockRelease(ReplicationSlotControlLock);
        ReplicationSlotDropAcquired();
        goto restart;
    }
    LWLockRelease(ReplicationSlotControlLock);
}

References ReplicationSlot::active_pid, ReplicationSlot::data, ReplicationSlotPersistentData::database, ereport, errcode(), errmsg(), ERROR, i, ReplicationSlot::in_use, LW_SHARED, LWLockAcquire(), LWLockRelease(), max_replication_slots, ReplicationSlot::mutex, MyProcPid, MyReplicationSlot, ReplicationSlotPersistentData::name, NameStr, ReplicationSlotCtlData::replication_slots, ReplicationSlotCtl, ReplicationSlotDropAcquired(), SlotIsLogical, SpinLockAcquire, and SpinLockRelease.

Referenced by dbase_redo(), and dropdb().

ReplicationSlotsShmemInit()

void ReplicationSlotsShmemInit

(

void

)

Definition at line 135 of file slot.c.

{
    bool        found;
 
    if (max_replication_slots == 0)
        return;
 
    ReplicationSlotCtl = (ReplicationSlotCtlData *)
        ShmemInitStruct("ReplicationSlot Ctl", ReplicationSlotsShmemSize(),
                        &found);
 
    if (!found)
    {
        int         i;
 
        /* First time through, so initialize */
        MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize());
 
        for (i = 0; i < max_replication_slots; i++)
        {
            ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i];
 
            /* everything else is zeroed by the memset above */
            SpinLockInit(&slot->mutex);
            LWLockInitialize(&slot->io_in_progress_lock,
                             LWTRANCHE_REPLICATION_SLOT_IO);
            ConditionVariableInit(&slot->active_cv);
        }
    }
}

References ReplicationSlot::active_cv, ConditionVariableInit(), i, ReplicationSlot::io_in_progress_lock, LWLockInitialize(), LWTRANCHE_REPLICATION_SLOT_IO, max_replication_slots, MemSet, ReplicationSlot::mutex, ReplicationSlotCtlData::replication_slots, ReplicationSlotCtl, ReplicationSlotsShmemSize(), ShmemInitStruct(), and SpinLockInit.

Referenced by CreateSharedMemoryAndSemaphores().

ReplicationSlotsShmemSize()

Size ReplicationSlotsShmemSize

(

void

)

Definition at line 117 of file slot.c.

{
    Size        size = 0;
 
    if (max_replication_slots == 0)
        return size;
 
    size = offsetof(ReplicationSlotCtlData, replication_slots);
    size = add_size(size,
                    mul_size(max_replication_slots, sizeof(ReplicationSlot)));
 
    return size;
}

References add_size(), max_replication_slots, and mul_size().

Referenced by CalculateShmemSize(), and ReplicationSlotsShmemInit().

ReplicationSlotValidateName()

bool ReplicationSlotValidateName	(	const char *	name,
		int	elevel
	)

Definition at line 198 of file slot.c.

{
    const char *cp;
 
    if (strlen(name) == 0)
    {
        ereport(elevel,
                (errcode(ERRCODE_INVALID_NAME),
                 errmsg("replication slot name \"%s\" is too short",
                        name)));
        return false;
    }
 
    if (strlen(name) >= NAMEDATALEN)
    {
        ereport(elevel,
                (errcode(ERRCODE_NAME_TOO_LONG),
                 errmsg("replication slot name \"%s\" is too long",
                        name)));
        return false;
    }
 
    for (cp = name; *cp; cp++)
    {
        if (!((*cp >= 'a' && *cp <= 'z')
              || (*cp >= '0' && *cp <= '9')
              || (*cp == '_')))
        {
            ereport(elevel,
                    (errcode(ERRCODE_INVALID_NAME),
                     errmsg("replication slot name \"%s\" contains invalid character",
                            name),
                     errhint("Replication slot names may only contain lower case letters, numbers, and the underscore character.")));
            return false;
        }
    }
    return true;
}

References ereport, errcode(), errhint(), errmsg(), name, and NAMEDATALEN.

Referenced by check_primary_slot_name(), parse_subscription_options(), ReplicationSlotCreate(), and StartupReorderBuffer().

SearchNamedReplicationSlot()

ReplicationSlot* SearchNamedReplicationSlot	(	const char *	name,
		bool	need_lock
	)

Definition at line 374 of file slot.c.

{
    int         i;
    ReplicationSlot *slot = NULL;
 
    if (need_lock)
        LWLockAcquire(ReplicationSlotControlLock, LW_SHARED);
 
    for (i = 0; i < max_replication_slots; i++)
    {
        ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i];
 
        if (s->in_use && strcmp(name, NameStr(s->data.name)) == 0)
        {
            slot = s;
            break;
        }
    }
 
    if (need_lock)
        LWLockRelease(ReplicationSlotControlLock);
 
    return slot;
}

References ReplicationSlot::data, i, ReplicationSlot::in_use, LW_SHARED, LWLockAcquire(), LWLockRelease(), max_replication_slots, name, ReplicationSlotPersistentData::name, NameStr, ReplicationSlotCtlData::replication_slots, and ReplicationSlotCtl.

Referenced by get_replslot_index(), pg_ls_replslotdir(), pgstat_reset_replslot(), ReadReplicationSlot(), and ReplicationSlotAcquire().

StartupReplicationSlots()

void StartupReplicationSlots

(

void

)

Definition at line 1477 of file slot.c.

{
    DIR        *replication_dir;
    struct dirent *replication_de;
 
    elog(DEBUG1, "starting up replication slots");
 
    /* restore all slots by iterating over all on-disk entries */
    replication_dir = AllocateDir("pg_replslot");
    while ((replication_de = ReadDir(replication_dir, "pg_replslot")) != NULL)
    {
        char        path[MAXPGPATH + 12];
        PGFileType  de_type;
 
        if (strcmp(replication_de->d_name, ".") == 0 ||
            strcmp(replication_de->d_name, "..") == 0)
            continue;
 
        snprintf(path, sizeof(path), "pg_replslot/%s", replication_de->d_name);
        de_type = get_dirent_type(path, replication_de, false, DEBUG1);
 
        /* we're only creating directories here, skip if it's not our's */
        if (de_type != PGFILETYPE_ERROR && de_type != PGFILETYPE_DIR)
            continue;
 
        /* we crashed while a slot was being setup or deleted, clean up */
        if (pg_str_endswith(replication_de->d_name, ".tmp"))
        {
            if (!rmtree(path, true))
            {
                ereport(WARNING,
                        (errmsg("could not remove directory \"%s\"",
                                path)));
                continue;
            }
            fsync_fname("pg_replslot", true);
            continue;
        }
 
        /* looks like a slot in a normal state, restore */
        RestoreSlotFromDisk(replication_de->d_name);
    }
    FreeDir(replication_dir);
 
    /* currently no slots exist, we're done. */
    if (max_replication_slots <= 0)
        return;
 
    /* Now that we have recovered all the data, compute replication xmin */
    ReplicationSlotsComputeRequiredXmin(false);
    ReplicationSlotsComputeRequiredLSN();
}

References AllocateDir(), dirent::d_name, DEBUG1, elog(), ereport, errmsg(), FreeDir(), fsync_fname(), get_dirent_type(), max_replication_slots, MAXPGPATH, pg_str_endswith(), PGFILETYPE_DIR, PGFILETYPE_ERROR, ReadDir(), ReplicationSlotsComputeRequiredLSN(), ReplicationSlotsComputeRequiredXmin(), RestoreSlotFromDisk(), rmtree(), snprintf, and WARNING.

Referenced by StartupXLOG().

Variable Documentation

max_replication_slots

PGDLLIMPORT int max_replication_slots

extern

Definition at line 101 of file slot.c.

Referenced by CheckPointReplicationOrigin(), CheckPointReplicationSlots(), CheckSlotRequirements(), copy_replication_slot(), InvalidateObsoleteReplicationSlots(), logicalrep_worker_launch(), pg_get_replication_slots(), pg_show_replication_origin_status(), ReplicationOriginShmemInit(), ReplicationOriginShmemSize(), ReplicationSlotCleanup(), ReplicationSlotCreate(), ReplicationSlotIndex(), ReplicationSlotsComputeLogicalRestartLSN(), ReplicationSlotsComputeRequiredLSN(), ReplicationSlotsComputeRequiredXmin(), ReplicationSlotsCountDBSlots(), ReplicationSlotsDropDBSlots(), ReplicationSlotsShmemInit(), ReplicationSlotsShmemSize(), replorigin_advance(), replorigin_check_prerequisites(), replorigin_get_progress(), replorigin_redo(), replorigin_session_reset(), replorigin_session_setup(), replorigin_state_clear(), RestoreSlotFromDisk(), SearchNamedReplicationSlot(), StartupReplicationOrigin(), and StartupReplicationSlots().

MyReplicationSlot

PGDLLIMPORT ReplicationSlot* MyReplicationSlot

extern

Definition at line 98 of file slot.c.

Referenced by copy_replication_slot(), create_logical_replication_slot(), create_physical_replication_slot(), CreateDecodingContext(), CreateInitDecodingContext(), CreateReplicationSlot(), InvalidatePossiblyObsoleteSlot(), LogicalConfirmReceivedLocation(), LogicalIncreaseRestartDecodingForSlot(), LogicalIncreaseXminForSlot(), pg_create_logical_replication_slot(), pg_create_physical_replication_slot(), pg_logical_replication_slot_advance(), pg_logical_slot_get_changes_guts(), pg_physical_replication_slot_advance(), pg_replication_slot_advance(), PhysicalConfirmReceivedLocation(), PhysicalReplicationSlotNewXmin(), PostgresMain(), ProcessStandbyHSFeedbackMessage(), ProcessStandbyReplyMessage(), ReorderBufferAllocate(), ReorderBufferFree(), ReorderBufferRestoreChanges(), ReorderBufferRestoreCleanup(), ReorderBufferSerializedPath(), ReorderBufferSerializeTXN(), ReplicationSlotAcquire(), ReplicationSlotCleanup(), ReplicationSlotCreate(), ReplicationSlotDrop(), ReplicationSlotDropAcquired(), ReplicationSlotMarkDirty(), ReplicationSlotPersist(), ReplicationSlotRelease(), ReplicationSlotReserveWal(), ReplicationSlotSave(), ReplicationSlotsDropDBSlots(), ReplicationSlotShmemExit(), StartLogicalReplication(), StartReplication(), StartupDecodingContext(), and WalSndErrorCleanup().

ReplicationSlotCtl

PGDLLIMPORT ReplicationSlotCtlData* ReplicationSlotCtl

extern

Definition at line 95 of file slot.c.

Referenced by CheckPointReplicationSlots(), copy_replication_slot(), InvalidateObsoleteReplicationSlots(), pg_get_replication_slots(), ReplicationSlotCleanup(), ReplicationSlotCreate(), ReplicationSlotIndex(), ReplicationSlotName(), ReplicationSlotsComputeLogicalRestartLSN(), ReplicationSlotsComputeRequiredLSN(), ReplicationSlotsComputeRequiredXmin(), ReplicationSlotsCountDBSlots(), ReplicationSlotsDropDBSlots(), ReplicationSlotsShmemInit(), RestoreSlotFromDisk(), and SearchNamedReplicationSlot().