From 41441dbd5b5d45d33da1d0d1a19ff813a47ba993 Mon Sep 17 00:00:00 2001 From: Zhijie Hou Date: Mon, 9 Feb 2026 12:47:59 +0800 Subject: [PATCH v5 1/4] Refactoring: remove some unnecessary func parameters in slotsync codes Previously, certain function parameters were used to store the reason for slot synchronization being skipped. However, now that a slot property serves this purpose, this commit simplifies the code by eliminating those redundant parameters and using the slot's property to perform the same check. --- src/backend/replication/logical/slotsync.c | 81 +++++++--------------- 1 file changed, 26 insertions(+), 55 deletions(-) diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index af5682ce50e..1ff81b58a6e 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -194,18 +194,9 @@ update_slotsync_skip_stats(SlotSyncSkipReason skip_reason) * * If no update was needed (the data of the remote slot is the same as the * local slot) return false, otherwise true. - * - * *found_consistent_snapshot will be true iff the remote slot's LSN or xmin is - * modified, and decoding from the corresponding LSN's can reach a - * consistent snapshot. - * - * *remote_slot_precedes will be true if the remote slot's LSN or xmin - * precedes locally reserved position. */ static bool -update_local_synced_slot(RemoteSlot *remote_slot, Oid remote_dbid, - bool *found_consistent_snapshot, - bool *remote_slot_precedes) +update_local_synced_slot(RemoteSlot *remote_slot, Oid remote_dbid) { ReplicationSlot *slot = MyReplicationSlot; bool updated_xmin_or_lsn = false; @@ -214,12 +205,6 @@ update_local_synced_slot(RemoteSlot *remote_slot, Oid remote_dbid, Assert(slot->data.invalidated == RS_INVAL_NONE); - if (found_consistent_snapshot) - *found_consistent_snapshot = false; - - if (remote_slot_precedes) - *remote_slot_precedes = false; - /* * Don't overwrite if we already have a newer catalog_xmin and * restart_lsn. @@ -262,9 +247,6 @@ update_local_synced_slot(RemoteSlot *remote_slot, Oid remote_dbid, LSN_FORMAT_ARGS(slot->data.restart_lsn), slot->data.catalog_xmin)); - if (remote_slot_precedes) - *remote_slot_precedes = true; - /* * Skip updating the configuration. This is required to avoid syncing * two_phase_at without syncing confirmed_lsn. Otherwise, the prepared @@ -304,14 +286,13 @@ update_local_synced_slot(RemoteSlot *remote_slot, Oid remote_dbid, slot->data.confirmed_flush = remote_slot->confirmed_lsn; slot->data.catalog_xmin = remote_slot->catalog_xmin; SpinLockRelease(&slot->mutex); - - if (found_consistent_snapshot) - *found_consistent_snapshot = true; } else { + bool found_consistent_snapshot; + LogicalSlotAdvanceAndCheckSnapState(remote_slot->confirmed_lsn, - found_consistent_snapshot); + &found_consistent_snapshot); /* Sanity check */ if (slot->data.confirmed_flush != remote_slot->confirmed_lsn) @@ -326,8 +307,18 @@ update_local_synced_slot(RemoteSlot *remote_slot, Oid remote_dbid, * If we can't reach a consistent snapshot, the slot won't be * persisted. See update_and_persist_local_synced_slot(). */ - if (found_consistent_snapshot && !(*found_consistent_snapshot)) + if (!found_consistent_snapshot) + { + Assert(MyReplicationSlot->data.persistency == RS_TEMPORARY); + + ereport(LOG, + errmsg("could not synchronize replication slot \"%s\"", + remote_slot->name), + errdetail("Synchronization could lead to data loss, because the standby could not build a consistent snapshot to decode WALs at LSN %X/%08X.", + LSN_FORMAT_ARGS(slot->data.restart_lsn))); + skip_reason = SS_SKIP_NO_CONSISTENT_SNAPSHOT; + } } updated_xmin_or_lsn = true; @@ -619,27 +610,26 @@ update_and_persist_local_synced_slot(RemoteSlot *remote_slot, Oid remote_dbid, bool *slot_persistence_pending) { ReplicationSlot *slot = MyReplicationSlot; - bool found_consistent_snapshot = false; - bool remote_slot_precedes = false; /* Slotsync skip stats are handled in function update_local_synced_slot() */ - (void) update_local_synced_slot(remote_slot, remote_dbid, - &found_consistent_snapshot, - &remote_slot_precedes); + (void) update_local_synced_slot(remote_slot, remote_dbid); /* - * Check if the primary server has caught up. Refer to the comment atop - * the file for details on this check. + * Check if the slot cannot be synchronized. Refer to the comment atop the + * file for details on this check. */ - if (remote_slot_precedes) + if (slot->slotsync_skip_reason != SS_SKIP_NONE) { /* - * The remote slot didn't catch up to locally reserved position. + * We reach here when the remote slot didn't catch up to locally + * reserved position, or it cannot reach the consistent point from the + * restart_lsn. * * We do not drop the slot because the restart_lsn can be ahead of the * current location when recreating the slot in the next cycle. It may - * take more time to create such a slot. Therefore, we keep this slot - * and attempt the synchronization in the next cycle. + * take more time to create such a slot or reach the consistent point. + * Therefore, we keep this slot and attempt the synchronization in the + * next cycle. * * We also update the slot_persistence_pending parameter, so the SQL * function can retry. @@ -650,24 +640,6 @@ update_and_persist_local_synced_slot(RemoteSlot *remote_slot, Oid remote_dbid, return false; } - /* - * Don't persist the slot if it cannot reach the consistent point from the - * restart_lsn. See comments atop this file. - */ - if (!found_consistent_snapshot) - { - ereport(LOG, - errmsg("could not synchronize replication slot \"%s\"", remote_slot->name), - errdetail("Synchronization could lead to data loss, because the standby could not build a consistent snapshot to decode WALs at LSN %X/%08X.", - LSN_FORMAT_ARGS(slot->data.restart_lsn))); - - /* Set this, so that SQL function can retry */ - if (slot_persistence_pending) - *slot_persistence_pending = true; - - return false; - } - ReplicationSlotPersist(); ereport(LOG, @@ -819,8 +791,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, LSN_FORMAT_ARGS(slot->data.confirmed_flush), LSN_FORMAT_ARGS(remote_slot->confirmed_lsn))); - slot_updated = update_local_synced_slot(remote_slot, remote_dbid, - NULL, NULL); + slot_updated = update_local_synced_slot(remote_slot, remote_dbid); } } /* Otherwise create the slot first. */ -- 2.51.1.windows.1