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

Include dependency graph for logical.h:

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

Go to the source code of this file.

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, bool skipped_xact)

typedef struct LogicalDecodingContext	LogicalDecodingContext

Functions
void	CheckLogicalDecodingRequirements (void)

LogicalDecodingContext *	CreateInitDecodingContext (const char plugin, List output_plugin_options, bool need_full_snapshot, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress)

LogicalDecodingContext *	CreateDecodingContext (XLogRecPtr start_lsn, List output_plugin_options, bool fast_forward, XLogReaderRoutine xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, LogicalOutputPluginWriterWrite do_write, LogicalOutputPluginWriterUpdateProgress update_progress)

void	DecodingContextFindStartpoint (LogicalDecodingContext *ctx)

bool	DecodingContextReady (LogicalDecodingContext *ctx)

void	FreeDecodingContext (LogicalDecodingContext *ctx)

void	LogicalIncreaseXminForSlot (XLogRecPtr current_lsn, TransactionId xmin)

void	LogicalIncreaseRestartDecodingForSlot (XLogRecPtr current_lsn, XLogRecPtr restart_lsn)

void	LogicalConfirmReceivedLocation (XLogRecPtr lsn)

bool	filter_prepare_cb_wrapper (LogicalDecodingContext ctx, TransactionId xid, const char gid)

bool	filter_by_origin_cb_wrapper (LogicalDecodingContext *ctx, RepOriginId origin_id)

void	ResetLogicalStreamingState (void)

void	UpdateDecodingStats (LogicalDecodingContext *ctx)

bool	LogicalReplicationSlotHasPendingWal (XLogRecPtr end_of_wal)

XLogRecPtr	LogicalSlotAdvanceAndCheckSnapState (XLogRecPtr moveto, bool *found_consistent_snapshot)

Typedef Documentation

◆ LogicalDecodingContext

typedef struct LogicalDecodingContext LogicalDecodingContext

◆ LogicalOutputPluginWriterPrepareWrite

typedef LogicalOutputPluginWriterWrite LogicalOutputPluginWriterPrepareWrite

Definition at line 25 of file logical.h.

◆ LogicalOutputPluginWriterUpdateProgress

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

Definition at line 27 of file logical.h.

◆ LogicalOutputPluginWriterWrite

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

Definition at line 19 of file logical.h.

Function Documentation

◆ CheckLogicalDecodingRequirements()

void CheckLogicalDecodingRequirements ( void )

Definition at line 109 of file logical.c.

 {
     CheckSlotRequirements();
  
     /*
      * NB: Adding a new requirement likely means that RestoreSlotFromDisk()
      * needs the same check.
      */
  
     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")));
  
     if (RecoveryInProgress())
     {
         /*
          * This check may have race conditions, but whenever
          * XLOG_PARAMETER_CHANGE indicates that wal_level has changed, we
          * verify that there are no existing logical replication slots. And to
          * avoid races around creating a new slot,
          * CheckLogicalDecodingRequirements() is called once before creating
          * the slot, and once when logical decoding is initially starting up.
          */
         if (GetActiveWalLevelOnStandby() < WAL_LEVEL_LOGICAL)
             ereport(ERROR,
                     (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                      errmsg("logical decoding on standby requires wal_level >= logical on the primary")));
     }
 }

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

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

◆ CreateDecodingContext()

LogicalDecodingContext* CreateDecodingContext	(	XLogRecPtr	start_lsn,
		List *	output_plugin_options,
		bool	fast_forward,
		XLogReaderRoutine *	xl_routine,
		LogicalOutputPluginWriterPrepareWrite	prepare_write,
		LogicalOutputPluginWriterWrite	do_write,
		LogicalOutputPluginWriterUpdateProgress	update_progress
	)

Definition at line 495 of file logical.c.

 {
     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")));
  
     /*
      * We need to access the system tables during decoding to build the
      * logical changes unless we are in fast_forward mode where no changes are
      * generated.
      */
     if (slot->data.database != MyDatabaseId && !fast_forward)
         ereport(ERROR,
                 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                  errmsg("replication slot \"%s\" was not created in this database",
                         NameStr(slot->data.name))));
  
     /*
      * The slots being synced from the primary can't be used for decoding as
      * they are used after failover. However, we do allow advancing the LSNs
      * during the synchronization of slots. See update_local_synced_slot.
      */
     if (RecoveryInProgress() && slot->data.synced && !IsSyncingReplicationSlots())
         ereport(ERROR,
                 errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("cannot use replication slot \"%s\" for logical decoding",
                        NameStr(slot->data.name)),
                 errdetail("This slot is being synchronized from the primary server."),
                 errhint("Specify another replication slot."));
  
     /*
      * Check if slot has been invalidated due to max_slot_wal_keep_size. Avoid
      * "cannot get changes" wording in this errmsg because that'd be
      * confusingly ambiguous about no changes being available when called from
      * pg_logical_slot_get_changes_guts().
      */
     if (MyReplicationSlot->data.invalidated == RS_INVAL_WAL_REMOVED)
         ereport(ERROR,
                 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                  errmsg("can no longer get changes from replication slot \"%s\"",
                         NameStr(MyReplicationSlot->data.name)),
                  errdetail("This slot has been invalidated because it exceeded the maximum reserved size.")));
  
     if (MyReplicationSlot->data.invalidated != RS_INVAL_NONE)
         ereport(ERROR,
                 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                  errmsg("can no longer get changes from replication slot \"%s\"",
                         NameStr(MyReplicationSlot->data.name)),
                  errdetail("This slot has been invalidated because it was conflicting with recovery.")));
  
     Assert(MyReplicationSlot->data.invalidated == RS_INVAL_NONE);
     Assert(MyReplicationSlot->data.restart_lsn != InvalidXLogRecPtr);
  
     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.
          *
          * Starting at a different LSN than requested might not catch certain
          * kinds of client errors; so the client may wish to check that
          * confirmed_flush_lsn matches its expectations.
          */
         elog(LOG, "%X/%X has been already streamed, forwarding to %X/%X",
              LSN_FORMAT_ARGS(start_lsn),
              LSN_FORMAT_ARGS(slot->data.confirmed_flush));
  
         start_lsn = slot->data.confirmed_flush;
     }
  
     ctx = StartupDecodingContext(output_plugin_options,
                                  start_lsn, InvalidTransactionId, false,
                                  fast_forward, xl_routine, 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);
  
     /*
      * We allow decoding of prepared transactions when the two_phase is
      * enabled at the time of slot creation, or when the two_phase option is
      * given at the streaming start, provided the plugin supports all the
      * callbacks for two-phase.
      */
     ctx->twophase &= (slot->data.two_phase || ctx->twophase_opt_given);
  
     /* Mark slot to allow two_phase decoding if not already marked */
     if (ctx->twophase && !slot->data.two_phase)
     {
         SpinLockAcquire(&slot->mutex);
         slot->data.two_phase = true;
         slot->data.two_phase_at = start_lsn;
         SpinLockRelease(&slot->mutex);
         ReplicationSlotMarkDirty();
         ReplicationSlotSave();
         SnapBuildSetTwoPhaseAt(ctx->snapshot_builder, start_lsn);
     }
  
     ctx->reorder->output_rewrites = ctx->options.receive_rewrites;
  
     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.",
                        LSN_FORMAT_ARGS(slot->data.confirmed_flush),
                        LSN_FORMAT_ARGS(slot->data.restart_lsn))));
  
     return ctx;
 }

Referenced by LogicalReplicationSlotHasPendingWal(), LogicalSlotAdvanceAndCheckSnapState(), pg_logical_slot_get_changes_guts(), and StartLogicalReplication().

◆ CreateInitDecodingContext()

LogicalDecodingContext* CreateInitDecodingContext	(	const char *	plugin,
		List *	output_plugin_options,
		bool	need_full_snapshot,
		XLogRecPtr	restart_lsn,
		XLogReaderRoutine *	xl_routine,
		LogicalOutputPluginWriterPrepareWrite	prepare_write,
		LogicalOutputPluginWriterWrite	do_write,
		LogicalOutputPluginWriterUpdateProgress	update_progress
	)

Definition at line 329 of file logical.c.

 {
     TransactionId xmin_horizon = InvalidTransactionId;
     ReplicationSlot *slot;
     NameData    plugin_name;
     LogicalDecodingContext *ctx;
     MemoryContext old_context;
  
     /*
      * On a standby, this check is also required while creating the slot.
      * Check the comments in the function.
      */
     CheckLogicalDecodingRequirements();
  
     /* 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.  We need the mutex to avoid
      * concurrent reading of a partially copied string.  But we don't want any
      * complicated code while holding a spinlock, so do namestrcpy() outside.
      */
     namestrcpy(&plugin_name, plugin);
     SpinLockAcquire(&slot->mutex);
     slot->data.plugin = plugin_name;
     SpinLockRelease(&slot->mutex);
  
     if (XLogRecPtrIsInvalid(restart_lsn))
         ReplicationSlotReserveWal();
     else
     {
         SpinLockAcquire(&slot->mutex);
         slot->data.restart_lsn = restart_lsn;
         SpinLockRelease(&slot->mutex);
     }
  
     /* ----
      * 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);
  
     SpinLockAcquire(&slot->mutex);
     slot->effective_catalog_xmin = xmin_horizon;
     slot->data.catalog_xmin = xmin_horizon;
     if (need_full_snapshot)
         slot->effective_xmin = xmin_horizon;
     SpinLockRelease(&slot->mutex);
  
     ReplicationSlotsComputeRequiredXmin(true);
  
     LWLockRelease(ProcArrayLock);
  
     ReplicationSlotMarkDirty();
     ReplicationSlotSave();
  
     ctx = StartupDecodingContext(NIL, restart_lsn, xmin_horizon,
                                  need_full_snapshot, false,
                                  xl_routine, 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);
  
     /*
      * We allow decoding of prepared transactions when the two_phase is
      * enabled at the time of slot creation, or when the two_phase option is
      * given at the streaming start, provided the plugin supports all the
      * callbacks for two-phase.
      */
     ctx->twophase &= slot->data.two_phase;
  
     ctx->reorder->output_rewrites = ctx->options.receive_rewrites;
  
     return ctx;
 }

References LogicalDecodingContext::callbacks, ReplicationSlotPersistentData::catalog_xmin, CheckLogicalDecodingRequirements(), LogicalDecodingContext::context, ReplicationSlot::data, ReplicationSlotPersistentData::database, ReplicationSlot::effective_catalog_xmin, ReplicationSlot::effective_xmin, elog, ereport, errcode(), errmsg(), ERROR, GetOldestSafeDecodingTransactionId(), GetTopTransactionIdIfAny(), InvalidTransactionId, IsTransactionState(), LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), MemoryContextSwitchTo(), ReplicationSlot::mutex, MyDatabaseId, MyReplicationSlot, ReplicationSlotPersistentData::name, NameStr, namestrcpy(), NIL, LogicalDecodingContext::options, ReorderBuffer::output_rewrites, plugin, ReplicationSlotPersistentData::plugin, OutputPluginOptions::receive_rewrites, LogicalDecodingContext::reorder, ReplicationSlotMarkDirty(), ReplicationSlotReserveWal(), ReplicationSlotSave(), ReplicationSlotsComputeRequiredXmin(), ReplicationSlotPersistentData::restart_lsn, SlotIsPhysical, SpinLockAcquire, SpinLockRelease, OutputPluginCallbacks::startup_cb, startup_cb_wrapper(), StartupDecodingContext(), ReplicationSlotPersistentData::two_phase, LogicalDecodingContext::twophase, and XLogRecPtrIsInvalid.

Referenced by create_logical_replication_slot(), and CreateReplicationSlot().

◆ DecodingContextFindStartpoint()

void DecodingContextFindStartpoint ( LogicalDecodingContext * ctx )

Definition at line 649 of file logical.c.

 {
     ReplicationSlot *slot = ctx->slot;
  
     /* Initialize from where to start reading WAL. */
     XLogBeginRead(ctx->reader, slot->data.restart_lsn);
  
     elog(DEBUG1, "searching for logical decoding starting point, starting at %X/%X",
          LSN_FORMAT_ARGS(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, &err);
         if (err)
             elog(ERROR, "could not find logical decoding starting point: %s", err);
         if (!record)
             elog(ERROR, "could not find logical decoding starting point");
  
         LogicalDecodingProcessRecord(ctx, ctx->reader);
  
         /* only continue till we found a consistent spot */
         if (DecodingContextReady(ctx))
             break;
  
         CHECK_FOR_INTERRUPTS();
     }
  
     SpinLockAcquire(&slot->mutex);
     slot->data.confirmed_flush = ctx->reader->EndRecPtr;
     if (slot->data.two_phase)
         slot->data.two_phase_at = ctx->reader->EndRecPtr;
     SpinLockRelease(&slot->mutex);
 }

References CHECK_FOR_INTERRUPTS, ReplicationSlotPersistentData::confirmed_flush, ReplicationSlot::data, DEBUG1, DecodingContextReady(), elog, XLogReaderState::EndRecPtr, err(), ERROR, LogicalDecodingProcessRecord(), LSN_FORMAT_ARGS, ReplicationSlot::mutex, LogicalDecodingContext::reader, ReplicationSlotPersistentData::restart_lsn, LogicalDecodingContext::slot, SpinLockAcquire, SpinLockRelease, ReplicationSlotPersistentData::two_phase, ReplicationSlotPersistentData::two_phase_at, XLogBeginRead(), and XLogReadRecord().

Referenced by create_logical_replication_slot(), and CreateReplicationSlot().

◆ DecodingContextReady()

bool DecodingContextReady ( LogicalDecodingContext * ctx )

Definition at line 640 of file logical.c.

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

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

Referenced by DecodingContextFindStartpoint(), and LogicalSlotAdvanceAndCheckSnapState().

◆ filter_by_origin_cb_wrapper()

bool filter_by_origin_cb_wrapper	(	LogicalDecodingContext *	ctx,
		RepOriginId	origin_id
	)

Definition at line 1215 of file logical.c.

 {
     LogicalErrorCallbackState state;
     ErrorContextCallback errcallback;
     bool        ret;
  
     Assert(!ctx->fast_forward);
  
     /* 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;
     ctx->end_xact = 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;
 }

References LogicalDecodingContext::accept_writes, ErrorContextCallback::arg, Assert, ErrorContextCallback::callback, LogicalDecodingContext::callbacks, LogicalDecodingContext::end_xact, error_context_stack, LogicalDecodingContext::fast_forward, OutputPluginCallbacks::filter_by_origin_cb, InvalidXLogRecPtr, output_plugin_error_callback(), and ErrorContextCallback::previous.

Referenced by FilterByOrigin().

◆ filter_prepare_cb_wrapper()

bool filter_prepare_cb_wrapper	(	LogicalDecodingContext *	ctx,
		TransactionId	xid,
		const char *	gid
	)

Definition at line 1183 of file logical.c.

 {
     LogicalErrorCallbackState state;
     ErrorContextCallback errcallback;
     bool        ret;
  
     Assert(!ctx->fast_forward);
  
     /* Push callback + info on the error context stack */
     state.ctx = ctx;
     state.callback_name = "filter_prepare";
     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;
     ctx->end_xact = false;
  
     /* do the actual work: call callback */
     ret = ctx->callbacks.filter_prepare_cb(ctx, xid, gid);
  
     /* Pop the error context stack */
     error_context_stack = errcallback.previous;
  
     return ret;
 }

References LogicalDecodingContext::accept_writes, ErrorContextCallback::arg, Assert, ErrorContextCallback::callback, LogicalDecodingContext::callbacks, LogicalDecodingContext::end_xact, error_context_stack, LogicalDecodingContext::fast_forward, OutputPluginCallbacks::filter_prepare_cb, InvalidXLogRecPtr, output_plugin_error_callback(), and ErrorContextCallback::previous.

Referenced by FilterPrepare().

◆ FreeDecodingContext()

void FreeDecodingContext ( LogicalDecodingContext * ctx )

Definition at line 693 of file logical.c.

 {
     if (ctx->callbacks.shutdown_cb != NULL)
         shutdown_cb_wrapper(ctx);
  
     ReorderBufferFree(ctx->reorder);
     FreeSnapshotBuilder(ctx->snapshot_builder);
     XLogReaderFree(ctx->reader);
     MemoryContextDelete(ctx->context);
 }

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

Referenced by create_logical_replication_slot(), CreateReplicationSlot(), LogicalReplicationSlotHasPendingWal(), LogicalSlotAdvanceAndCheckSnapState(), pg_logical_slot_get_changes_guts(), and StartLogicalReplication().

◆ LogicalConfirmReceivedLocation()

void LogicalConfirmReceivedLocation ( XLogRecPtr lsn )

Definition at line 1834 of file logical.c.

 {
     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);
     }
 }

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(), LogicalSlotAdvanceAndCheckSnapState(), pg_logical_slot_get_changes_guts(), and ProcessStandbyReplyMessage().

◆ LogicalIncreaseRestartDecodingForSlot()

void LogicalIncreaseRestartDecodingForSlot	(	XLogRecPtr	current_lsn,
		XLogRecPtr	restart_lsn
	)

Definition at line 1760 of file logical.c.

 {
     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;
         SpinLockRelease(&slot->mutex);
  
         elog(DEBUG1, "got new restart lsn %X/%X at %X/%X",
              LSN_FORMAT_ARGS(restart_lsn),
              LSN_FORMAT_ARGS(current_lsn));
     }
     else
     {
         XLogRecPtr  candidate_restart_lsn;
         XLogRecPtr  candidate_restart_valid;
         XLogRecPtr  confirmed_flush;
  
         candidate_restart_lsn = slot->candidate_restart_lsn;
         candidate_restart_valid = slot->candidate_restart_valid;
         confirmed_flush = slot->data.confirmed_flush;
         SpinLockRelease(&slot->mutex);
  
         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",
              LSN_FORMAT_ARGS(restart_lsn),
              LSN_FORMAT_ARGS(current_lsn),
              LSN_FORMAT_ARGS(candidate_restart_lsn),
              LSN_FORMAT_ARGS(candidate_restart_valid),
              LSN_FORMAT_ARGS(confirmed_flush));
     }
  
     /* candidates are already valid with the current flush position, apply */
     if (updated_lsn)
         LogicalConfirmReceivedLocation(slot->data.confirmed_flush);
 }

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

Referenced by SnapBuildProcessRunningXacts().

◆ LogicalIncreaseXminForSlot()

void LogicalIncreaseXminForSlot	(	XLogRecPtr	current_lsn,
		TransactionId	xmin
	)

Definition at line 1692 of file logical.c.

 {
     bool        updated_xmin = false;
     ReplicationSlot *slot;
     bool        got_new_xmin = false;
  
     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;
  
         /*
          * Log new xmin at an appropriate log level after releasing the
          * spinlock.
          */
         got_new_xmin = true;
     }
     SpinLockRelease(&slot->mutex);
  
     if (got_new_xmin)
         elog(DEBUG1, "got new catalog xmin %u at %X/%X", xmin,
              LSN_FORMAT_ARGS(current_lsn));
  
     /* candidate already valid with the current flush position, apply */
     if (updated_xmin)
         LogicalConfirmReceivedLocation(slot->data.confirmed_flush);
 }

References Assert, ReplicationSlot::candidate_catalog_xmin, ReplicationSlot::candidate_xmin_lsn, ReplicationSlotPersistentData::catalog_xmin, ReplicationSlotPersistentData::confirmed_flush, ReplicationSlot::data, data, DEBUG1, elog, InvalidXLogRecPtr, LogicalConfirmReceivedLocation(), LSN_FORMAT_ARGS, ReplicationSlot::mutex, MyReplicationSlot, SpinLockAcquire, SpinLockRelease, and TransactionIdPrecedesOrEquals().

Referenced by SnapBuildProcessRunningXacts().

◆ LogicalReplicationSlotHasPendingWal()

bool LogicalReplicationSlotHasPendingWal ( XLogRecPtr end_of_wal )

Definition at line 1978 of file logical.c.

 {
     bool        has_pending_wal = false;
  
     Assert(MyReplicationSlot);
  
     PG_TRY();
     {
         LogicalDecodingContext *ctx;
  
         /*
          * Create our decoding context in fast_forward mode, passing start_lsn
          * as InvalidXLogRecPtr, so that we start processing from the slot's
          * confirmed_flush.
          */
         ctx = CreateDecodingContext(InvalidXLogRecPtr,
                                     NIL,
                                     true,   /* fast_forward */
                                     XL_ROUTINE(.page_read = read_local_xlog_page,
                                                .segment_open = wal_segment_open,
                                                .segment_close = wal_segment_close),
                                     NULL, NULL, NULL);
  
         /*
          * Start reading at the slot's restart_lsn, which we know points to a
          * valid record.
          */
         XLogBeginRead(ctx->reader, MyReplicationSlot->data.restart_lsn);
  
         /* Invalidate non-timetravel entries */
         InvalidateSystemCaches();
  
         /* Loop until the end of WAL or some changes are processed */
         while (!has_pending_wal && ctx->reader->EndRecPtr < end_of_wal)
         {
             XLogRecord *record;
             char       *errm = NULL;
  
             record = XLogReadRecord(ctx->reader, &errm);
  
             if (errm)
                 elog(ERROR, "could not find record for logical decoding: %s", errm);
  
             if (record != NULL)
                 LogicalDecodingProcessRecord(ctx, ctx->reader);
  
             has_pending_wal = ctx->processing_required;
  
             CHECK_FOR_INTERRUPTS();
         }
  
         /* Clean up */
         FreeDecodingContext(ctx);
         InvalidateSystemCaches();
     }
     PG_CATCH();
     {
         /* clear all timetravel entries */
         InvalidateSystemCaches();
  
         PG_RE_THROW();
     }
     PG_END_TRY();
  
     return has_pending_wal;
 }

References Assert, CHECK_FOR_INTERRUPTS, CreateDecodingContext(), ReplicationSlot::data, elog, XLogReaderState::EndRecPtr, ERROR, FreeDecodingContext(), InvalidateSystemCaches(), InvalidXLogRecPtr, LogicalDecodingProcessRecord(), MyReplicationSlot, NIL, PG_CATCH, PG_END_TRY, PG_RE_THROW, PG_TRY, LogicalDecodingContext::processing_required, read_local_xlog_page(), LogicalDecodingContext::reader, ReplicationSlotPersistentData::restart_lsn, wal_segment_close(), wal_segment_open(), XL_ROUTINE, XLogBeginRead(), and XLogReadRecord().

Referenced by binary_upgrade_logical_slot_has_caught_up().

◆ LogicalSlotAdvanceAndCheckSnapState()

XLogRecPtr LogicalSlotAdvanceAndCheckSnapState	(	XLogRecPtr	moveto,
		bool *	found_consistent_snapshot
	)

Definition at line 2060 of file logical.c.

 {
     LogicalDecodingContext *ctx;
     ResourceOwner old_resowner = CurrentResourceOwner;
     XLogRecPtr  retlsn;
  
     Assert(moveto != InvalidXLogRecPtr);
  
     if (found_consistent_snapshot)
         *found_consistent_snapshot = false;
  
     PG_TRY();
     {
         /*
          * Create our decoding context in fast_forward mode, passing start_lsn
          * as InvalidXLogRecPtr, so that we start processing from my slot's
          * confirmed_flush.
          */
         ctx = CreateDecodingContext(InvalidXLogRecPtr,
                                     NIL,
                                     true,   /* fast_forward */
                                     XL_ROUTINE(.page_read = read_local_xlog_page,
                                                .segment_open = wal_segment_open,
                                                .segment_close = wal_segment_close),
                                     NULL, NULL, NULL);
  
         /*
          * Wait for specified streaming replication standby servers (if any)
          * to confirm receipt of WAL up to moveto lsn.
          */
         WaitForStandbyConfirmation(moveto);
  
         /*
          * Start reading at the slot's restart_lsn, which we know to point to
          * a valid record.
          */
         XLogBeginRead(ctx->reader, MyReplicationSlot->data.restart_lsn);
  
         /* invalidate non-timetravel entries */
         InvalidateSystemCaches();
  
         /* Decode records until we reach the requested target */
         while (ctx->reader->EndRecPtr < moveto)
         {
             char       *errm = NULL;
             XLogRecord *record;
  
             /*
              * Read records.  No changes are generated in fast_forward mode,
              * but snapbuilder/slot statuses are updated properly.
              */
             record = XLogReadRecord(ctx->reader, &errm);
             if (errm)
                 elog(ERROR, "could not find record while advancing replication slot: %s",
                      errm);
  
             /*
              * Process the record.  Storage-level changes are ignored in
              * fast_forward mode, but other modules (such as snapbuilder)
              * might still have critical updates to do.
              */
             if (record)
                 LogicalDecodingProcessRecord(ctx, ctx->reader);
  
             CHECK_FOR_INTERRUPTS();
         }
  
         if (found_consistent_snapshot && DecodingContextReady(ctx))
             *found_consistent_snapshot = true;
  
         /*
          * Logical decoding could have clobbered CurrentResourceOwner during
          * transaction management, so restore the executor's value.  (This is
          * a kluge, but it's not worth cleaning up right now.)
          */
         CurrentResourceOwner = old_resowner;
  
         if (ctx->reader->EndRecPtr != InvalidXLogRecPtr)
         {
             LogicalConfirmReceivedLocation(moveto);
  
             /*
              * If only the confirmed_flush LSN has changed the slot won't get
              * marked as dirty by the above. Callers on the walsender
              * interface are expected to keep track of their own progress and
              * don't need it written out. But SQL-interface users cannot
              * specify their own start positions and it's harder for them to
              * keep track of their progress, so we should make more of an
              * effort to save it for them.
              *
              * Dirty the slot so it is written out at the next checkpoint. The
              * LSN position advanced to may still be lost on a crash but this
              * makes the data consistent after a clean shutdown.
              */
             ReplicationSlotMarkDirty();
         }
  
         retlsn = MyReplicationSlot->data.confirmed_flush;
  
         /* free context, call shutdown callback */
         FreeDecodingContext(ctx);
  
         InvalidateSystemCaches();
     }
     PG_CATCH();
     {
         /* clear all timetravel entries */
         InvalidateSystemCaches();
  
         PG_RE_THROW();
     }
     PG_END_TRY();
  
     return retlsn;
 }

References Assert, CHECK_FOR_INTERRUPTS, ReplicationSlotPersistentData::confirmed_flush, CreateDecodingContext(), CurrentResourceOwner, ReplicationSlot::data, DecodingContextReady(), elog, XLogReaderState::EndRecPtr, ERROR, FreeDecodingContext(), InvalidateSystemCaches(), InvalidXLogRecPtr, LogicalConfirmReceivedLocation(), LogicalDecodingProcessRecord(), MyReplicationSlot, NIL, PG_CATCH, PG_END_TRY, PG_RE_THROW, PG_TRY, read_local_xlog_page(), LogicalDecodingContext::reader, ReplicationSlotMarkDirty(), ReplicationSlotPersistentData::restart_lsn, WaitForStandbyConfirmation(), wal_segment_close(), wal_segment_open(), XL_ROUTINE, XLogBeginRead(), and XLogReadRecord().

Referenced by pg_logical_replication_slot_advance(), and update_local_synced_slot().

◆ ResetLogicalStreamingState()

void ResetLogicalStreamingState ( void )

Definition at line 1921 of file logical.c.

 {
     CheckXidAlive = InvalidTransactionId;
     bsysscan = false;
 }

References bsysscan, CheckXidAlive, and InvalidTransactionId.

Referenced by AbortSubTransaction(), and AbortTransaction().

◆ UpdateDecodingStats()

void UpdateDecodingStats ( LogicalDecodingContext * ctx )

Definition at line 1931 of file logical.c.

 {
     ReorderBuffer *rb = ctx->reorder;
     PgStat_StatReplSlotEntry repSlotStat;
  
     /* Nothing to do if we don't have any replication stats to be sent. */
     if (rb->spillBytes <= 0 && rb->streamBytes <= 0 && rb->totalBytes <= 0)
         return;
  
     elog(DEBUG2, "UpdateDecodingStats: updating stats %p %lld %lld %lld %lld %lld %lld %lld %lld",
          rb,
          (long long) rb->spillTxns,
          (long long) rb->spillCount,
          (long long) rb->spillBytes,
          (long long) rb->streamTxns,
          (long long) rb->streamCount,
          (long long) rb->streamBytes,
          (long long) rb->totalTxns,
          (long long) rb->totalBytes);
  
     repSlotStat.spill_txns = rb->spillTxns;
     repSlotStat.spill_count = rb->spillCount;
     repSlotStat.spill_bytes = rb->spillBytes;
     repSlotStat.stream_txns = rb->streamTxns;
     repSlotStat.stream_count = rb->streamCount;
     repSlotStat.stream_bytes = rb->streamBytes;
     repSlotStat.total_txns = rb->totalTxns;
     repSlotStat.total_bytes = rb->totalBytes;
  
     pgstat_report_replslot(ctx->slot, &repSlotStat);
  
     rb->spillTxns = 0;
     rb->spillCount = 0;
     rb->spillBytes = 0;
     rb->streamTxns = 0;
     rb->streamCount = 0;
     rb->streamBytes = 0;
     rb->totalTxns = 0;
     rb->totalBytes = 0;
 }

Referenced by DecodeAbort(), DecodeCommit(), DecodePrepare(), ReorderBufferSerializeTXN(), and ReorderBufferStreamTXN().

Data Structures

Typedefs

Functions