From 943f7ae1c8693cf3ea59d103aaf9590ea062fb9c Mon Sep 17 00:00:00 2001 From: Michael Paquier Date: Thu, 22 Feb 2024 08:40:40 +0900 Subject: [PATCH] Add lookup table for replication slot conflict reasons This commit switches the handling of the conflict cause strings for replication slots to use a table rather than being explicitly listed, using a C99-designated initializer syntax for the array elements. This makes the whole more readable while easing future maintenance with less areas to update when adding a new conflict reason. This is similar to 74a730631065, but the scale of the change is smaller as there are less conflict causes than LWLock builtin tranche names. Author: Bharath Rupireddy Reviewed-by: Jelte Fennema-Nio Discussion: https://postgr.es/m/CALj2ACUxSLA91QGFrJsWNKs58KXb1C03mbuwKmzqqmoAKLwJaw@mail.gmail.com --- src/backend/replication/slot.c | 45 ++++++++++++++++++++--------- src/backend/replication/slotfuncs.c | 24 ++++----------- src/include/replication/slot.h | 13 ++++----- 3 files changed, 43 insertions(+), 39 deletions(-) diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a142855bd32..233652b4799 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -77,6 +77,22 @@ typedef struct ReplicationSlotOnDisk ReplicationSlotPersistentData slotdata; } ReplicationSlotOnDisk; +/* + * Lookup table for slot invalidation causes. + */ +const char *const SlotInvalidationCauses[] = { + [RS_INVAL_NONE] = "none", + [RS_INVAL_WAL_REMOVED] = "wal_removed", + [RS_INVAL_HORIZON] = "rows_removed", + [RS_INVAL_WAL_LEVEL] = "wal_level_insufficient", +}; + +/* Maximum number of invalidation causes */ +#define RS_INVAL_MAX_CAUSES RS_INVAL_WAL_LEVEL + +StaticAssertDecl(lengthof(SlotInvalidationCauses) == (RS_INVAL_MAX_CAUSES + 1), + "array length mismatch"); + /* size of version independent data */ #define ReplicationSlotOnDiskConstantSize \ offsetof(ReplicationSlotOnDisk, slotdata) @@ -2290,23 +2306,26 @@ RestoreSlotFromDisk(const char *name) } /* - * Maps the pg_replication_slots.conflict_reason text value to - * ReplicationSlotInvalidationCause enum value + * Maps a conflict reason for a replication slot to + * ReplicationSlotInvalidationCause. */ ReplicationSlotInvalidationCause -GetSlotInvalidationCause(char *conflict_reason) +GetSlotInvalidationCause(const char *conflict_reason) { + ReplicationSlotInvalidationCause cause; + bool found PG_USED_FOR_ASSERTS_ONLY = false; + Assert(conflict_reason); - if (strcmp(conflict_reason, SLOT_INVAL_WAL_REMOVED_TEXT) == 0) - return RS_INVAL_WAL_REMOVED; - else if (strcmp(conflict_reason, SLOT_INVAL_HORIZON_TEXT) == 0) - return RS_INVAL_HORIZON; - else if (strcmp(conflict_reason, SLOT_INVAL_WAL_LEVEL_TEXT) == 0) - return RS_INVAL_WAL_LEVEL; - else - Assert(0); + for (cause = RS_INVAL_NONE; cause <= RS_INVAL_MAX_CAUSES; cause++) + { + if (strcmp(SlotInvalidationCauses[cause], conflict_reason) == 0) + { + found = true; + break; + } + } - /* Keep compiler quiet */ - return RS_INVAL_NONE; + Assert(found); + return cause; } diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index d2fa5e669a3..c108bf9608f 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -413,24 +413,12 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) nulls[i++] = true; else { - switch (slot_contents.data.invalidated) - { - case RS_INVAL_NONE: - nulls[i++] = true; - break; - - case RS_INVAL_WAL_REMOVED: - values[i++] = CStringGetTextDatum(SLOT_INVAL_WAL_REMOVED_TEXT); - break; - - case RS_INVAL_HORIZON: - values[i++] = CStringGetTextDatum(SLOT_INVAL_HORIZON_TEXT); - break; - - case RS_INVAL_WAL_LEVEL: - values[i++] = CStringGetTextDatum(SLOT_INVAL_WAL_LEVEL_TEXT); - break; - } + ReplicationSlotInvalidationCause cause = slot_contents.data.invalidated; + + if (cause == RS_INVAL_NONE) + nulls[i++] = true; + else + values[i++] = CStringGetTextDatum(SlotInvalidationCauses[cause]); } values[i++] = BoolGetDatum(slot_contents.data.failover); diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index e706ca834c0..acbf567150e 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -40,6 +40,9 @@ typedef enum ReplicationSlotPersistency /* * Slots can be invalidated, e.g. due to max_slot_wal_keep_size. If so, the * 'invalidated' field is set to a value other than _NONE. + * + * When adding a new invalidation cause here, remember to update + * SlotInvalidationCauses and RS_INVAL_MAX_CAUSES. */ typedef enum ReplicationSlotInvalidationCause { @@ -52,13 +55,7 @@ typedef enum ReplicationSlotInvalidationCause RS_INVAL_WAL_LEVEL, } ReplicationSlotInvalidationCause; -/* - * The possible values for 'conflict_reason' returned in - * pg_get_replication_slots. - */ -#define SLOT_INVAL_WAL_REMOVED_TEXT "wal_removed" -#define SLOT_INVAL_HORIZON_TEXT "rows_removed" -#define SLOT_INVAL_WAL_LEVEL_TEXT "wal_level_insufficient" +extern PGDLLIMPORT const char *const SlotInvalidationCauses[]; /* * On-Disk data of a replication slot, preserved across restarts. @@ -275,6 +272,6 @@ extern void CheckPointReplicationSlots(bool is_shutdown); extern void CheckSlotRequirements(void); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause - GetSlotInvalidationCause(char *conflict_reason); + GetSlotInvalidationCause(const char *conflict_reason); #endif /* SLOT_H */ -- 2.30.2