logical.h File Reference

#include "replication/slot.h"
#include "access/xlog.h"
#include "access/xlogreader.h"
#include "replication/output_plugin.h"

Include dependency graph for logical.h:

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Data Structures
struct	LogicalDecodingContext

Typedefs
typedef void(*	LogicalOutputPluginWriterWrite )(struct LogicalDecodingContext *lr, XLogRecPtr Ptr, TransactionId xid, bool last_write)
typedef LogicalOutputPluginWriterWrite	LogicalOutputPluginWriterPrepareWrite
typedef void(*	LogicalOutputPluginWriterUpdateProgress )(struct LogicalDecodingContext *lr, XLogRecPtr Ptr, TransactionId xid)
typedef struct LogicalDecodingContext	LogicalDecodingContext

Functions
void	CheckLogicalDecodingRequirements (void)
LogicalDecodingContext *	CreateInitDecodingContext (char *plugin, List *output_plugin_options, bool need_full_snapshot, XLogPageReadCB read_page, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress)
LogicalDecodingContext *	CreateDecodingContext (XLogRecPtr start_lsn, List *output_plugin_options, XLogPageReadCB read_page, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress)
void	DecodingContextFindStartpoint (LogicalDecodingContext *ctx)
bool	DecodingContextReady (LogicalDecodingContext *ctx)
void	FreeDecodingContext (LogicalDecodingContext *ctx)
void	LogicalIncreaseXminForSlot (XLogRecPtr lsn, TransactionId xmin)
void	LogicalIncreaseRestartDecodingForSlot (XLogRecPtr current_lsn, XLogRecPtr restart_lsn)
void	LogicalConfirmReceivedLocation (XLogRecPtr lsn)
bool	filter_by_origin_cb_wrapper (LogicalDecodingContext *ctx, RepOriginId origin_id)

Typedef Documentation

typedef struct LogicalDecodingContext LogicalDecodingContext

typedef LogicalOutputPluginWriterWrite LogicalOutputPluginWriterPrepareWrite

Definition at line 27 of file logical.h.

typedef void(* LogicalOutputPluginWriterUpdateProgress)(struct LogicalDecodingContext *lr, XLogRecPtr Ptr, TransactionId xid)

Definition at line 29 of file logical.h.

typedef void(* LogicalOutputPluginWriterWrite)(struct LogicalDecodingContext *lr, XLogRecPtr Ptr, TransactionId xid, bool last_write)

Definition at line 20 of file logical.h.

Function Documentation

void CheckLogicalDecodingRequirements

(

void

)

Definition at line 76 of file logical.c.

References CheckSlotRequirements(), ereport, errcode(), errmsg(), ERROR, InvalidOid, MyDatabaseId, RecoveryInProgress(), wal_level, and WAL_LEVEL_LOGICAL.

Referenced by CreateReplicationSlot(), pg_create_logical_replication_slot(), pg_logical_slot_get_changes_guts(), and StartLogicalReplication().

{
    CheckSlotRequirements();

    if (wal_level < WAL_LEVEL_LOGICAL)
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("logical decoding requires wal_level >= logical")));

    if (MyDatabaseId == InvalidOid)
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("logical decoding requires a database connection")));

    /* ----
     * TODO: We got to change that someday soon...
     *
     * There's basically three things missing to allow this:
     * 1) We need to be able to correctly and quickly identify the timeline a
     *    LSN belongs to
     * 2) We need to force hot_standby_feedback to be enabled at all times so
     *    the primary cannot remove rows we need.
     * 3) support dropping replication slots referring to a database, in
     *    dbase_redo. There can't be any active ones due to HS recovery
     *    conflicts, so that should be relatively easy.
     * ----
     */
    if (RecoveryInProgress())
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("logical decoding cannot be used while in recovery")));
}

LogicalDecodingContext* CreateDecodingContext	(	XLogRecPtr	start_lsn,
		List *	output_plugin_options,
		XLogPageReadCB	read_page,
		LogicalOutputPluginWriterPrepareWrite	prepare_write,
		LogicalOutputPluginWriterWrite	do_write,
		LogicalOutputPluginWriterUpdateProgress	update_progress
	)

Definition at line 343 of file logical.c.

References LogicalDecodingContext::callbacks, ReplicationSlotPersistentData::confirmed_flush, LogicalDecodingContext::context, ReplicationSlot::data, ReplicationSlotPersistentData::database, DEBUG1, elog, ereport, errcode(), errdetail(), errmsg(), ERROR, InvalidTransactionId, InvalidXLogRecPtr, LOG, MemoryContextSwitchTo(), MyDatabaseId, MyReplicationSlot, ReplicationSlotPersistentData::name, NameStr, NULL, LogicalDecodingContext::options, ReplicationSlotPersistentData::restart_lsn, SlotIsPhysical, OutputPluginCallbacks::startup_cb, startup_cb_wrapper(), and StartupDecodingContext().

Referenced by pg_logical_slot_get_changes_guts(), and StartLogicalReplication().

{
    LogicalDecodingContext *ctx;
    ReplicationSlot *slot;
    MemoryContext old_context;

    /* shorter lines... */
    slot = MyReplicationSlot;

    /* first some sanity checks that are unlikely to be violated */
    if (slot == NULL)
        elog(ERROR, "cannot perform logical decoding without an acquired slot");

    /* make sure the passed slot is suitable, these are user facing errors */
    if (SlotIsPhysical(slot))
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 (errmsg("cannot use physical replication slot for logical decoding"))));

    if (slot->data.database != MyDatabaseId)
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 (errmsg("replication slot \"%s\" was not created in this database",
                         NameStr(slot->data.name)))));

    if (start_lsn == InvalidXLogRecPtr)
    {
        /* continue from last position */
        start_lsn = slot->data.confirmed_flush;
    }
    else if (start_lsn < slot->data.confirmed_flush)
    {
        /*
         * It might seem like we should error out in this case, but it's
         * pretty common for a client to acknowledge a LSN it doesn't have to
         * do anything for, and thus didn't store persistently, because the
         * xlog records didn't result in anything relevant for logical
         * decoding. Clients have to be able to do that to support synchronous
         * replication.
         */
        elog(DEBUG1, "cannot stream from %X/%X, minimum is %X/%X, forwarding",
             (uint32) (start_lsn >> 32), (uint32) start_lsn,
             (uint32) (slot->data.confirmed_flush >> 32),
             (uint32) slot->data.confirmed_flush);

        start_lsn = slot->data.confirmed_flush;
    }

    ctx = StartupDecodingContext(output_plugin_options,
                                 start_lsn, InvalidTransactionId, false,
                                 read_page, prepare_write, do_write,
                                 update_progress);

    /* call output plugin initialization callback */
    old_context = MemoryContextSwitchTo(ctx->context);
    if (ctx->callbacks.startup_cb != NULL)
        startup_cb_wrapper(ctx, &ctx->options, false);
    MemoryContextSwitchTo(old_context);

    ereport(LOG,
            (errmsg("starting logical decoding for slot \"%s\"",
                    NameStr(slot->data.name)),
             errdetail("streaming transactions committing after %X/%X, reading WAL from %X/%X",
                       (uint32) (slot->data.confirmed_flush >> 32),
                       (uint32) slot->data.confirmed_flush,
                       (uint32) (slot->data.restart_lsn >> 32),
                       (uint32) slot->data.restart_lsn)));

    return ctx;
}

LogicalDecodingContext* CreateInitDecodingContext	(	char *	plugin,
		List *	output_plugin_options,
		bool	need_full_snapshot,
		XLogPageReadCB	read_page,
		LogicalOutputPluginWriterPrepareWrite	prepare_write,
		LogicalOutputPluginWriterWrite	do_write,
		LogicalOutputPluginWriterUpdateProgress	update_progress
	)

Definition at line 216 of file logical.c.

References LogicalDecodingContext::callbacks, ReplicationSlotPersistentData::catalog_xmin, LogicalDecodingContext::context, ReplicationSlot::data, ReplicationSlotPersistentData::database, ReplicationSlot::effective_catalog_xmin, ReplicationSlot::effective_xmin, elog, ereport, errcode(), errmsg(), ERROR, GetOldestSafeDecodingTransactionId(), GetTopTransactionIdIfAny(), InvalidTransactionId, InvalidXLogRecPtr, IsTransactionState(), LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), MemoryContextSwitchTo(), ReplicationSlot::mutex, MyDatabaseId, MyReplicationSlot, ReplicationSlotPersistentData::name, NAMEDATALEN, NameStr, NIL, NULL, LogicalDecodingContext::options, ReplicationSlotPersistentData::plugin, ReplicationSlotMarkDirty(), ReplicationSlotReserveWal(), ReplicationSlotSave(), ReplicationSlotsComputeRequiredXmin(), SlotIsPhysical, SpinLockAcquire, SpinLockRelease, OutputPluginCallbacks::startup_cb, startup_cb_wrapper(), StartupDecodingContext(), and StrNCpy.

Referenced by CreateReplicationSlot(), and pg_create_logical_replication_slot().

{
    TransactionId xmin_horizon = InvalidTransactionId;
    ReplicationSlot *slot;
    LogicalDecodingContext *ctx;
    MemoryContext old_context;

    /* shorter lines... */
    slot = MyReplicationSlot;

    /* first some sanity checks that are unlikely to be violated */
    if (slot == NULL)
        elog(ERROR, "cannot perform logical decoding without an acquired slot");

    if (plugin == NULL)
        elog(ERROR, "cannot initialize logical decoding without a specified plugin");

    /* Make sure the passed slot is suitable. These are user facing errors. */
    if (SlotIsPhysical(slot))
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("cannot use physical replication slot for logical decoding")));

    if (slot->data.database != MyDatabaseId)
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("replication slot \"%s\" was not created in this database",
                        NameStr(slot->data.name))));

    if (IsTransactionState() &&
        GetTopTransactionIdIfAny() != InvalidTransactionId)
        ereport(ERROR,
                (errcode(ERRCODE_ACTIVE_SQL_TRANSACTION),
                 errmsg("cannot create logical replication slot in transaction that has performed writes")));

    /* register output plugin name with slot */
    SpinLockAcquire(&slot->mutex);
    StrNCpy(NameStr(slot->data.plugin), plugin, NAMEDATALEN);
    SpinLockRelease(&slot->mutex);

    ReplicationSlotReserveWal();

    /* ----
     * This is a bit tricky: We need to determine a safe xmin horizon to start
     * decoding from, to avoid starting from a running xacts record referring
     * to xids whose rows have been vacuumed or pruned
     * already. GetOldestSafeDecodingTransactionId() returns such a value, but
     * without further interlock its return value might immediately be out of
     * date.
     *
     * So we have to acquire the ProcArrayLock to prevent computation of new
     * xmin horizons by other backends, get the safe decoding xid, and inform
     * the slot machinery about the new limit. Once that's done the
     * ProcArrayLock can be released as the slot machinery now is
     * protecting against vacuum.
     *
     * Note that, temporarily, the data, not just the catalog, xmin has to be
     * reserved if a data snapshot is to be exported.  Otherwise the initial
     * data snapshot created here is not guaranteed to be valid. After that
     * the data xmin doesn't need to be managed anymore and the global xmin
     * should be recomputed. As we are fine with losing the pegged data xmin
     * after crash - no chance a snapshot would get exported anymore - we can
     * get away with just setting the slot's
     * effective_xmin. ReplicationSlotRelease will reset it again.
     *
     * ----
     */
    LWLockAcquire(ProcArrayLock, LW_EXCLUSIVE);

    xmin_horizon = GetOldestSafeDecodingTransactionId(need_full_snapshot);

    slot->effective_catalog_xmin = xmin_horizon;
    slot->data.catalog_xmin = xmin_horizon;
    if (need_full_snapshot)
        slot->effective_xmin = xmin_horizon;

    ReplicationSlotsComputeRequiredXmin(true);

    LWLockRelease(ProcArrayLock);

    ReplicationSlotMarkDirty();
    ReplicationSlotSave();

    ctx = StartupDecodingContext(NIL, InvalidXLogRecPtr, xmin_horizon,
                                 need_full_snapshot, read_page, prepare_write,
                                 do_write, update_progress);

    /* call output plugin initialization callback */
    old_context = MemoryContextSwitchTo(ctx->context);
    if (ctx->callbacks.startup_cb != NULL)
        startup_cb_wrapper(ctx, &ctx->options, true);
    MemoryContextSwitchTo(old_context);

    return ctx;
}

void DecodingContextFindStartpoint

(

LogicalDecodingContext *

ctx

)

Definition at line 432 of file logical.c.

References CHECK_FOR_INTERRUPTS, ReplicationSlotPersistentData::confirmed_flush, ReplicationSlot::data, DEBUG1, DecodingContextReady(), elog, XLogReaderState::EndRecPtr, ERROR, InvalidXLogRecPtr, LogicalDecodingProcessRecord(), NULL, LogicalDecodingContext::reader, ReplicationSlotPersistentData::restart_lsn, LogicalDecodingContext::slot, and XLogReadRecord().

Referenced by CreateReplicationSlot(), and pg_create_logical_replication_slot().

{
    XLogRecPtr  startptr;

    /* Initialize from where to start reading WAL. */
    startptr = ctx->slot->data.restart_lsn;

    elog(DEBUG1, "searching for logical decoding starting point, starting at %X/%X",
         (uint32) (ctx->slot->data.restart_lsn >> 32),
         (uint32) ctx->slot->data.restart_lsn);

    /* Wait for a consistent starting point */
    for (;;)
    {
        XLogRecord *record;
        char       *err = NULL;

        /* the read_page callback waits for new WAL */
        record = XLogReadRecord(ctx->reader, startptr, &err);
        if (err)
            elog(ERROR, "%s", err);
        if (!record)
            elog(ERROR, "no record found"); /* shouldn't happen */

        startptr = InvalidXLogRecPtr;

        LogicalDecodingProcessRecord(ctx, ctx->reader);

        /* only continue till we found a consistent spot */
        if (DecodingContextReady(ctx))
            break;

        CHECK_FOR_INTERRUPTS();
    }

    ctx->slot->data.confirmed_flush = ctx->reader->EndRecPtr;
}

bool DecodingContextReady

(

LogicalDecodingContext *

ctx

)

Definition at line 423 of file logical.c.

References SNAPBUILD_CONSISTENT, SnapBuildCurrentState(), and LogicalDecodingContext::snapshot_builder.

Referenced by DecodingContextFindStartpoint().

{
    return SnapBuildCurrentState(ctx->snapshot_builder) == SNAPBUILD_CONSISTENT;
}

bool filter_by_origin_cb_wrapper	(	LogicalDecodingContext *	ctx,
		RepOriginId	origin_id
	)

Definition at line 718 of file logical.c.

References LogicalDecodingContext::accept_writes, ErrorContextCallback::arg, ErrorContextCallback::callback, LogicalErrorCallbackState::callback_name, LogicalDecodingContext::callbacks, LogicalErrorCallbackState::ctx, error_context_stack, OutputPluginCallbacks::filter_by_origin_cb, InvalidXLogRecPtr, output_plugin_error_callback(), ErrorContextCallback::previous, and LogicalErrorCallbackState::report_location.

Referenced by FilterByOrigin().

{
    LogicalErrorCallbackState state;
    ErrorContextCallback errcallback;
    bool        ret;

    /* Push callback + info on the error context stack */
    state.ctx = ctx;
    state.callback_name = "filter_by_origin";
    state.report_location = InvalidXLogRecPtr;
    errcallback.callback = output_plugin_error_callback;
    errcallback.arg = (void *) &state;
    errcallback.previous = error_context_stack;
    error_context_stack = &errcallback;

    /* set output state */
    ctx->accept_writes = false;

    /* do the actual work: call callback */
    ret = ctx->callbacks.filter_by_origin_cb(ctx, origin_id);

    /* Pop the error context stack */
    error_context_stack = errcallback.previous;

    return ret;
}

void FreeDecodingContext

(

LogicalDecodingContext *

ctx

)

Definition at line 475 of file logical.c.

References LogicalDecodingContext::callbacks, LogicalDecodingContext::context, FreeSnapshotBuilder(), MemoryContextDelete(), NULL, LogicalDecodingContext::reader, LogicalDecodingContext::reorder, ReorderBufferFree(), OutputPluginCallbacks::shutdown_cb, shutdown_cb_wrapper(), LogicalDecodingContext::snapshot_builder, and XLogReaderFree().

Referenced by CreateReplicationSlot(), pg_create_logical_replication_slot(), pg_logical_slot_get_changes_guts(), and StartLogicalReplication().

{
    if (ctx->callbacks.shutdown_cb != NULL)
        shutdown_cb_wrapper(ctx);

    ReorderBufferFree(ctx->reorder);
    FreeSnapshotBuilder(ctx->snapshot_builder);
    XLogReaderFree(ctx->reader);
    MemoryContextDelete(ctx->context);
}

void LogicalConfirmReceivedLocation

(

XLogRecPtr

lsn

)

Definition at line 914 of file logical.c.

References Assert, ReplicationSlot::candidate_catalog_xmin, ReplicationSlot::candidate_restart_lsn, ReplicationSlot::candidate_restart_valid, ReplicationSlot::candidate_xmin_lsn, ReplicationSlotPersistentData::catalog_xmin, ReplicationSlotPersistentData::confirmed_flush, ReplicationSlot::data, DEBUG1, ReplicationSlot::effective_catalog_xmin, elog, InvalidTransactionId, InvalidXLogRecPtr, ReplicationSlot::mutex, MyReplicationSlot, ReplicationSlotMarkDirty(), ReplicationSlotSave(), ReplicationSlotsComputeRequiredLSN(), ReplicationSlotsComputeRequiredXmin(), ReplicationSlotPersistentData::restart_lsn, SpinLockAcquire, SpinLockRelease, and TransactionIdIsValid.

Referenced by LogicalIncreaseRestartDecodingForSlot(), LogicalIncreaseXminForSlot(), pg_logical_slot_get_changes_guts(), and ProcessStandbyReplyMessage().

{
    Assert(lsn != InvalidXLogRecPtr);

    /* Do an unlocked check for candidate_lsn first. */
    if (MyReplicationSlot->candidate_xmin_lsn != InvalidXLogRecPtr ||
        MyReplicationSlot->candidate_restart_valid != InvalidXLogRecPtr)
    {
        bool        updated_xmin = false;
        bool        updated_restart = false;

        SpinLockAcquire(&MyReplicationSlot->mutex);

        MyReplicationSlot->data.confirmed_flush = lsn;

        /* if we're past the location required for bumping xmin, do so */
        if (MyReplicationSlot->candidate_xmin_lsn != InvalidXLogRecPtr &&
            MyReplicationSlot->candidate_xmin_lsn <= lsn)
        {
            /*
             * We have to write the changed xmin to disk *before* we change
             * the in-memory value, otherwise after a crash we wouldn't know
             * that some catalog tuples might have been removed already.
             *
             * Ensure that by first writing to ->xmin and only update
             * ->effective_xmin once the new state is synced to disk. After a
             * crash ->effective_xmin is set to ->xmin.
             */
            if (TransactionIdIsValid(MyReplicationSlot->candidate_catalog_xmin) &&
                MyReplicationSlot->data.catalog_xmin != MyReplicationSlot->candidate_catalog_xmin)
            {
                MyReplicationSlot->data.catalog_xmin = MyReplicationSlot->candidate_catalog_xmin;
                MyReplicationSlot->candidate_catalog_xmin = InvalidTransactionId;
                MyReplicationSlot->candidate_xmin_lsn = InvalidXLogRecPtr;
                updated_xmin = true;
            }
        }

        if (MyReplicationSlot->candidate_restart_valid != InvalidXLogRecPtr &&
            MyReplicationSlot->candidate_restart_valid <= lsn)
        {
            Assert(MyReplicationSlot->candidate_restart_lsn != InvalidXLogRecPtr);

            MyReplicationSlot->data.restart_lsn = MyReplicationSlot->candidate_restart_lsn;
            MyReplicationSlot->candidate_restart_lsn = InvalidXLogRecPtr;
            MyReplicationSlot->candidate_restart_valid = InvalidXLogRecPtr;
            updated_restart = true;
        }

        SpinLockRelease(&MyReplicationSlot->mutex);

        /* first write new xmin to disk, so we know what's up after a crash */
        if (updated_xmin || updated_restart)
        {
            ReplicationSlotMarkDirty();
            ReplicationSlotSave();
            elog(DEBUG1, "updated xmin: %u restart: %u", updated_xmin, updated_restart);
        }

        /*
         * Now the new xmin is safely on disk, we can let the global value
         * advance. We do not take ProcArrayLock or similar since we only
         * advance xmin here and there's not much harm done by a concurrent
         * computation missing that.
         */
        if (updated_xmin)
        {
            SpinLockAcquire(&MyReplicationSlot->mutex);
            MyReplicationSlot->effective_catalog_xmin = MyReplicationSlot->data.catalog_xmin;
            SpinLockRelease(&MyReplicationSlot->mutex);

            ReplicationSlotsComputeRequiredXmin(false);
            ReplicationSlotsComputeRequiredLSN();
        }
    }
    else
    {
        SpinLockAcquire(&MyReplicationSlot->mutex);
        MyReplicationSlot->data.confirmed_flush = lsn;
        SpinLockRelease(&MyReplicationSlot->mutex);
    }
}

void LogicalIncreaseRestartDecodingForSlot	(	XLogRecPtr	current_lsn,
		XLogRecPtr	restart_lsn
	)

Definition at line 845 of file logical.c.

References Assert, ReplicationSlot::candidate_restart_lsn, ReplicationSlot::candidate_restart_valid, ReplicationSlotPersistentData::confirmed_flush, ReplicationSlot::data, DEBUG1, elog, InvalidXLogRecPtr, LogicalConfirmReceivedLocation(), ReplicationSlot::mutex, MyReplicationSlot, NULL, SpinLockAcquire, and SpinLockRelease.

Referenced by SnapBuildProcessRunningXacts().

{
    bool        updated_lsn = false;
    ReplicationSlot *slot;

    slot = MyReplicationSlot;

    Assert(slot != NULL);
    Assert(restart_lsn != InvalidXLogRecPtr);
    Assert(current_lsn != InvalidXLogRecPtr);

    SpinLockAcquire(&slot->mutex);

    /* don't overwrite if have a newer restart lsn */
    if (restart_lsn <= slot->data.restart_lsn)
    {
    }

    /*
     * We might have already flushed far enough to directly accept this lsn,
     * in this case there is no need to check for existing candidate LSNs
     */
    else if (current_lsn <= slot->data.confirmed_flush)
    {
        slot->candidate_restart_valid = current_lsn;
        slot->candidate_restart_lsn = restart_lsn;

        /* our candidate can directly be used */
        updated_lsn = true;
    }

    /*
     * Only increase if the previous values have been applied, otherwise we
     * might never end up updating if the receiver acks too slowly. A missed
     * value here will just cause some extra effort after reconnecting.
     */
    if (slot->candidate_restart_valid == InvalidXLogRecPtr)
    {
        slot->candidate_restart_valid = current_lsn;
        slot->candidate_restart_lsn = restart_lsn;

        elog(DEBUG1, "got new restart lsn %X/%X at %X/%X",
             (uint32) (restart_lsn >> 32), (uint32) restart_lsn,
             (uint32) (current_lsn >> 32), (uint32) current_lsn);
    }
    else
    {
        elog(DEBUG1, "failed to increase restart lsn: proposed %X/%X, after %X/%X, current candidate %X/%X, current after %X/%X, flushed up to %X/%X",
             (uint32) (restart_lsn >> 32), (uint32) restart_lsn,
             (uint32) (current_lsn >> 32), (uint32) current_lsn,
             (uint32) (slot->candidate_restart_lsn >> 32),
             (uint32) slot->candidate_restart_lsn,
             (uint32) (slot->candidate_restart_valid >> 32),
             (uint32) slot->candidate_restart_valid,
             (uint32) (slot->data.confirmed_flush >> 32),
             (uint32) slot->data.confirmed_flush
            );
    }
    SpinLockRelease(&slot->mutex);

    /* candidates are already valid with the current flush position, apply */
    if (updated_lsn)
        LogicalConfirmReceivedLocation(slot->data.confirmed_flush);
}

void LogicalIncreaseXminForSlot	(	XLogRecPtr	lsn,
		TransactionId	xmin
	)

Definition at line 788 of file logical.c.

References Assert, ReplicationSlot::candidate_catalog_xmin, ReplicationSlot::candidate_xmin_lsn, ReplicationSlotPersistentData::catalog_xmin, ReplicationSlotPersistentData::confirmed_flush, ReplicationSlot::data, InvalidXLogRecPtr, LogicalConfirmReceivedLocation(), ReplicationSlot::mutex, MyReplicationSlot, NULL, SpinLockAcquire, SpinLockRelease, and TransactionIdPrecedesOrEquals().

Referenced by SnapBuildProcessRunningXacts().

{
    bool        updated_xmin = false;
    ReplicationSlot *slot;

    slot = MyReplicationSlot;

    Assert(slot != NULL);

    SpinLockAcquire(&slot->mutex);

    /*
     * don't overwrite if we already have a newer xmin. This can happen if we
     * restart decoding in a slot.
     */
    if (TransactionIdPrecedesOrEquals(xmin, slot->data.catalog_xmin))
    {
    }

    /*
     * If the client has already confirmed up to this lsn, we directly can
     * mark this as accepted. This can happen if we restart decoding in a
     * slot.
     */
    else if (current_lsn <= slot->data.confirmed_flush)
    {
        slot->candidate_catalog_xmin = xmin;
        slot->candidate_xmin_lsn = current_lsn;

        /* our candidate can directly be used */
        updated_xmin = true;
    }

    /*
     * Only increase if the previous values have been applied, otherwise we
     * might never end up updating if the receiver acks too slowly.
     */
    else if (slot->candidate_xmin_lsn == InvalidXLogRecPtr)
    {
        slot->candidate_catalog_xmin = xmin;
        slot->candidate_xmin_lsn = current_lsn;
    }
    SpinLockRelease(&slot->mutex);

    /* candidate already valid with the current flush position, apply */
    if (updated_xmin)
        LogicalConfirmReceivedLocation(slot->data.confirmed_flush);
}