wait_event.c

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/* ----------
 * wait_event.c
 *    Wait event reporting infrastructure.
 *
 * Copyright (c) 2001-2023, PostgreSQL Global Development Group
 *
 *
 * IDENTIFICATION
 *    src/backend/utils/activity/wait_event.c
 *
 * NOTES
 *
 * To make pgstat_report_wait_start() and pgstat_report_wait_end() as
 * lightweight as possible, they do not check if shared memory (MyProc
 * specifically, where the wait event is stored) is already available. Instead
 * we initially set my_wait_event_info to a process local variable, which then
 * is redirected to shared memory using pgstat_set_wait_event_storage(). For
 * the same reason pgstat_track_activities is not checked - the check adds
 * more work than it saves.
 *
 * ----------
 */
#include "postgres.h"
 
#include "storage/lmgr.h"       /* for GetLockNameFromTagType */
#include "storage/lwlock.h"     /* for GetLWLockIdentifier */
#include "utils/wait_event.h"
 
 
static const char *pgstat_get_wait_activity(WaitEventActivity w);
static const char *pgstat_get_wait_client(WaitEventClient w);
static const char *pgstat_get_wait_ipc(WaitEventIPC w);
static const char *pgstat_get_wait_timeout(WaitEventTimeout w);
static const char *pgstat_get_wait_io(WaitEventIO w);
 
 
static uint32 local_my_wait_event_info;
uint32     *my_wait_event_info = &local_my_wait_event_info;
 
 
/*
 * Configure wait event reporting to report wait events to *wait_event_info.
 * *wait_event_info needs to be valid until pgstat_reset_wait_event_storage()
 * is called.
 *
 * Expected to be called during backend startup, to point my_wait_event_info
 * into shared memory.
 */
void
pgstat_set_wait_event_storage(uint32 *wait_event_info)
{
    my_wait_event_info = wait_event_info;
}
 
/*
 * Reset wait event storage location.
 *
 * Expected to be called during backend shutdown, before the location set up
 * pgstat_set_wait_event_storage() becomes invalid.
 */
void
pgstat_reset_wait_event_storage(void)
{
    my_wait_event_info = &local_my_wait_event_info;
}
 
/* ----------
 * pgstat_get_wait_event_type() -
 *
 *  Return a string representing the current wait event type, backend is
 *  waiting on.
 */
const char *
pgstat_get_wait_event_type(uint32 wait_event_info)
{
    uint32      classId;
    const char *event_type;
 
    /* report process as not waiting. */
    if (wait_event_info == 0)
        return NULL;
 
    classId = wait_event_info & 0xFF000000;
 
    switch (classId)
    {
        case PG_WAIT_LWLOCK:
            event_type = "LWLock";
            break;
        case PG_WAIT_LOCK:
            event_type = "Lock";
            break;
        case PG_WAIT_BUFFER_PIN:
            event_type = "BufferPin";
            break;
        case PG_WAIT_ACTIVITY:
            event_type = "Activity";
            break;
        case PG_WAIT_CLIENT:
            event_type = "Client";
            break;
        case PG_WAIT_EXTENSION:
            event_type = "Extension";
            break;
        case PG_WAIT_IPC:
            event_type = "IPC";
            break;
        case PG_WAIT_TIMEOUT:
            event_type = "Timeout";
            break;
        case PG_WAIT_IO:
            event_type = "IO";
            break;
        default:
            event_type = "???";
            break;
    }
 
    return event_type;
}
 
/* ----------
 * pgstat_get_wait_event() -
 *
 *  Return a string representing the current wait event, backend is
 *  waiting on.
 */
const char *
pgstat_get_wait_event(uint32 wait_event_info)
{
    uint32      classId;
    uint16      eventId;
    const char *event_name;
 
    /* report process as not waiting. */
    if (wait_event_info == 0)
        return NULL;
 
    classId = wait_event_info & 0xFF000000;
    eventId = wait_event_info & 0x0000FFFF;
 
    switch (classId)
    {
        case PG_WAIT_LWLOCK:
            event_name = GetLWLockIdentifier(classId, eventId);
            break;
        case PG_WAIT_LOCK:
            event_name = GetLockNameFromTagType(eventId);
            break;
        case PG_WAIT_BUFFER_PIN:
            event_name = "BufferPin";
            break;
        case PG_WAIT_ACTIVITY:
            {
                WaitEventActivity w = (WaitEventActivity) wait_event_info;
 
                event_name = pgstat_get_wait_activity(w);
                break;
            }
        case PG_WAIT_CLIENT:
            {
                WaitEventClient w = (WaitEventClient) wait_event_info;
 
                event_name = pgstat_get_wait_client(w);
                break;
            }
        case PG_WAIT_EXTENSION:
            event_name = "Extension";
            break;
        case PG_WAIT_IPC:
            {
                WaitEventIPC w = (WaitEventIPC) wait_event_info;
 
                event_name = pgstat_get_wait_ipc(w);
                break;
            }
        case PG_WAIT_TIMEOUT:
            {
                WaitEventTimeout w = (WaitEventTimeout) wait_event_info;
 
                event_name = pgstat_get_wait_timeout(w);
                break;
            }
        case PG_WAIT_IO:
            {
                WaitEventIO w = (WaitEventIO) wait_event_info;
 
                event_name = pgstat_get_wait_io(w);
                break;
            }
        default:
            event_name = "unknown wait event";
            break;
    }
 
    return event_name;
}
 
/* ----------
 * pgstat_get_wait_activity() -
 *
 * Convert WaitEventActivity to string.
 * ----------
 */
static const char *
pgstat_get_wait_activity(WaitEventActivity w)
{
    const char *event_name = "unknown wait event";
 
    switch (w)
    {
        case WAIT_EVENT_ARCHIVER_MAIN:
            event_name = "ArchiverMain";
            break;
        case WAIT_EVENT_AUTOVACUUM_MAIN:
            event_name = "AutoVacuumMain";
            break;
        case WAIT_EVENT_BGWRITER_HIBERNATE:
            event_name = "BgWriterHibernate";
            break;
        case WAIT_EVENT_BGWRITER_MAIN:
            event_name = "BgWriterMain";
            break;
        case WAIT_EVENT_CHECKPOINTER_MAIN:
            event_name = "CheckpointerMain";
            break;
        case WAIT_EVENT_LOGICAL_APPLY_MAIN:
            event_name = "LogicalApplyMain";
            break;
        case WAIT_EVENT_LOGICAL_LAUNCHER_MAIN:
            event_name = "LogicalLauncherMain";
            break;
        case WAIT_EVENT_LOGICAL_PARALLEL_APPLY_MAIN:
            event_name = "LogicalParallelApplyMain";
            break;
        case WAIT_EVENT_RECOVERY_WAL_STREAM:
            event_name = "RecoveryWalStream";
            break;
        case WAIT_EVENT_SYSLOGGER_MAIN:
            event_name = "SysLoggerMain";
            break;
        case WAIT_EVENT_WAL_RECEIVER_MAIN:
            event_name = "WalReceiverMain";
            break;
        case WAIT_EVENT_WAL_SENDER_MAIN:
            event_name = "WalSenderMain";
            break;
        case WAIT_EVENT_WAL_WRITER_MAIN:
            event_name = "WalWriterMain";
            break;
            /* no default case, so that compiler will warn */
    }
 
    return event_name;
}
 
/* ----------
 * pgstat_get_wait_client() -
 *
 * Convert WaitEventClient to string.
 * ----------
 */
static const char *
pgstat_get_wait_client(WaitEventClient w)
{
    const char *event_name = "unknown wait event";
 
    switch (w)
    {
        case WAIT_EVENT_CLIENT_READ:
            event_name = "ClientRead";
            break;
        case WAIT_EVENT_CLIENT_WRITE:
            event_name = "ClientWrite";
            break;
        case WAIT_EVENT_GSS_OPEN_SERVER:
            event_name = "GSSOpenServer";
            break;
        case WAIT_EVENT_LIBPQWALRECEIVER_CONNECT:
            event_name = "LibPQWalReceiverConnect";
            break;
        case WAIT_EVENT_LIBPQWALRECEIVER_RECEIVE:
            event_name = "LibPQWalReceiverReceive";
            break;
        case WAIT_EVENT_SSL_OPEN_SERVER:
            event_name = "SSLOpenServer";
            break;
        case WAIT_EVENT_WAL_SENDER_WAIT_WAL:
            event_name = "WalSenderWaitForWAL";
            break;
        case WAIT_EVENT_WAL_SENDER_WRITE_DATA:
            event_name = "WalSenderWriteData";
            break;
            /* no default case, so that compiler will warn */
    }
 
    return event_name;
}
 
/* ----------
 * pgstat_get_wait_ipc() -
 *
 * Convert WaitEventIPC to string.
 * ----------
 */
static const char *
pgstat_get_wait_ipc(WaitEventIPC w)
{
    const char *event_name = "unknown wait event";
 
    switch (w)
    {
        case WAIT_EVENT_APPEND_READY:
            event_name = "AppendReady";
            break;
        case WAIT_EVENT_ARCHIVE_CLEANUP_COMMAND:
            event_name = "ArchiveCleanupCommand";
            break;
        case WAIT_EVENT_ARCHIVE_COMMAND:
            event_name = "ArchiveCommand";
            break;
        case WAIT_EVENT_BACKEND_TERMINATION:
            event_name = "BackendTermination";
            break;
        case WAIT_EVENT_BACKUP_WAIT_WAL_ARCHIVE:
            event_name = "BackupWaitWalArchive";
            break;
        case WAIT_EVENT_BGWORKER_SHUTDOWN:
            event_name = "BgWorkerShutdown";
            break;
        case WAIT_EVENT_BGWORKER_STARTUP:
            event_name = "BgWorkerStartup";
            break;
        case WAIT_EVENT_BTREE_PAGE:
            event_name = "BtreePage";
            break;
        case WAIT_EVENT_BUFFER_IO:
            event_name = "BufferIO";
            break;
        case WAIT_EVENT_CHECKPOINT_DONE:
            event_name = "CheckpointDone";
            break;
        case WAIT_EVENT_CHECKPOINT_START:
            event_name = "CheckpointStart";
            break;
        case WAIT_EVENT_EXECUTE_GATHER:
            event_name = "ExecuteGather";
            break;
        case WAIT_EVENT_HASH_BATCH_ALLOCATE:
            event_name = "HashBatchAllocate";
            break;
        case WAIT_EVENT_HASH_BATCH_ELECT:
            event_name = "HashBatchElect";
            break;
        case WAIT_EVENT_HASH_BATCH_LOAD:
            event_name = "HashBatchLoad";
            break;
        case WAIT_EVENT_HASH_BUILD_ALLOCATE:
            event_name = "HashBuildAllocate";
            break;
        case WAIT_EVENT_HASH_BUILD_ELECT:
            event_name = "HashBuildElect";
            break;
        case WAIT_EVENT_HASH_BUILD_HASH_INNER:
            event_name = "HashBuildHashInner";
            break;
        case WAIT_EVENT_HASH_BUILD_HASH_OUTER:
            event_name = "HashBuildHashOuter";
            break;
        case WAIT_EVENT_HASH_GROW_BATCHES_DECIDE:
            event_name = "HashGrowBatchesDecide";
            break;
        case WAIT_EVENT_HASH_GROW_BATCHES_ELECT:
            event_name = "HashGrowBatchesElect";
            break;
        case WAIT_EVENT_HASH_GROW_BATCHES_FINISH:
            event_name = "HashGrowBatchesFinish";
            break;
        case WAIT_EVENT_HASH_GROW_BATCHES_REALLOCATE:
            event_name = "HashGrowBatchesReallocate";
            break;
        case WAIT_EVENT_HASH_GROW_BATCHES_REPARTITION:
            event_name = "HashGrowBatchesRepartition";
            break;
        case WAIT_EVENT_HASH_GROW_BUCKETS_ELECT:
            event_name = "HashGrowBucketsElect";
            break;
        case WAIT_EVENT_HASH_GROW_BUCKETS_REALLOCATE:
            event_name = "HashGrowBucketsReallocate";
            break;
        case WAIT_EVENT_HASH_GROW_BUCKETS_REINSERT:
            event_name = "HashGrowBucketsReinsert";
            break;
        case WAIT_EVENT_LOGICAL_APPLY_SEND_DATA:
            event_name = "LogicalApplySendData";
            break;
        case WAIT_EVENT_LOGICAL_PARALLEL_APPLY_STATE_CHANGE:
            event_name = "LogicalParallelApplyStateChange";
            break;
        case WAIT_EVENT_LOGICAL_SYNC_DATA:
            event_name = "LogicalSyncData";
            break;
        case WAIT_EVENT_LOGICAL_SYNC_STATE_CHANGE:
            event_name = "LogicalSyncStateChange";
            break;
        case WAIT_EVENT_MQ_INTERNAL:
            event_name = "MessageQueueInternal";
            break;
        case WAIT_EVENT_MQ_PUT_MESSAGE:
            event_name = "MessageQueuePutMessage";
            break;
        case WAIT_EVENT_MQ_RECEIVE:
            event_name = "MessageQueueReceive";
            break;
        case WAIT_EVENT_MQ_SEND:
            event_name = "MessageQueueSend";
            break;
        case WAIT_EVENT_PARALLEL_BITMAP_SCAN:
            event_name = "ParallelBitmapScan";
            break;
        case WAIT_EVENT_PARALLEL_CREATE_INDEX_SCAN:
            event_name = "ParallelCreateIndexScan";
            break;
        case WAIT_EVENT_PARALLEL_FINISH:
            event_name = "ParallelFinish";
            break;
        case WAIT_EVENT_PROCARRAY_GROUP_UPDATE:
            event_name = "ProcArrayGroupUpdate";
            break;
        case WAIT_EVENT_PROC_SIGNAL_BARRIER:
            event_name = "ProcSignalBarrier";
            break;
        case WAIT_EVENT_PROMOTE:
            event_name = "Promote";
            break;
        case WAIT_EVENT_RECOVERY_CONFLICT_SNAPSHOT:
            event_name = "RecoveryConflictSnapshot";
            break;
        case WAIT_EVENT_RECOVERY_CONFLICT_TABLESPACE:
            event_name = "RecoveryConflictTablespace";
            break;
        case WAIT_EVENT_RECOVERY_END_COMMAND:
            event_name = "RecoveryEndCommand";
            break;
        case WAIT_EVENT_RECOVERY_PAUSE:
            event_name = "RecoveryPause";
            break;
        case WAIT_EVENT_REPLICATION_ORIGIN_DROP:
            event_name = "ReplicationOriginDrop";
            break;
        case WAIT_EVENT_REPLICATION_SLOT_DROP:
            event_name = "ReplicationSlotDrop";
            break;
        case WAIT_EVENT_RESTORE_COMMAND:
            event_name = "RestoreCommand";
            break;
        case WAIT_EVENT_SAFE_SNAPSHOT:
            event_name = "SafeSnapshot";
            break;
        case WAIT_EVENT_SYNC_REP:
            event_name = "SyncRep";
            break;
        case WAIT_EVENT_WAL_RECEIVER_EXIT:
            event_name = "WalReceiverExit";
            break;
        case WAIT_EVENT_WAL_RECEIVER_WAIT_START:
            event_name = "WalReceiverWaitStart";
            break;
        case WAIT_EVENT_XACT_GROUP_UPDATE:
            event_name = "XactGroupUpdate";
            break;
            /* no default case, so that compiler will warn */
    }
 
    return event_name;
}
 
/* ----------
 * pgstat_get_wait_timeout() -
 *
 * Convert WaitEventTimeout to string.
 * ----------
 */
static const char *
pgstat_get_wait_timeout(WaitEventTimeout w)
{
    const char *event_name = "unknown wait event";
 
    switch (w)
    {
        case WAIT_EVENT_BASE_BACKUP_THROTTLE:
            event_name = "BaseBackupThrottle";
            break;
        case WAIT_EVENT_CHECKPOINT_WRITE_DELAY:
            event_name = "CheckpointWriteDelay";
            break;
        case WAIT_EVENT_PG_SLEEP:
            event_name = "PgSleep";
            break;
        case WAIT_EVENT_RECOVERY_APPLY_DELAY:
            event_name = "RecoveryApplyDelay";
            break;
        case WAIT_EVENT_RECOVERY_RETRIEVE_RETRY_INTERVAL:
            event_name = "RecoveryRetrieveRetryInterval";
            break;
        case WAIT_EVENT_REGISTER_SYNC_REQUEST:
            event_name = "RegisterSyncRequest";
            break;
        case WAIT_EVENT_SPIN_DELAY:
            event_name = "SpinDelay";
            break;
        case WAIT_EVENT_VACUUM_DELAY:
            event_name = "VacuumDelay";
            break;
        case WAIT_EVENT_VACUUM_TRUNCATE:
            event_name = "VacuumTruncate";
            break;
            /* no default case, so that compiler will warn */
    }
 
    return event_name;
}
 
/* ----------
 * pgstat_get_wait_io() -
 *
 * Convert WaitEventIO to string.
 * ----------
 */
static const char *
pgstat_get_wait_io(WaitEventIO w)
{
    const char *event_name = "unknown wait event";
 
    switch (w)
    {
        case WAIT_EVENT_BASEBACKUP_READ:
            event_name = "BaseBackupRead";
            break;
        case WAIT_EVENT_BASEBACKUP_SYNC:
            event_name = "BaseBackupSync";
            break;
        case WAIT_EVENT_BASEBACKUP_WRITE:
            event_name = "BaseBackupWrite";
            break;
        case WAIT_EVENT_BUFFILE_READ:
            event_name = "BufFileRead";
            break;
        case WAIT_EVENT_BUFFILE_WRITE:
            event_name = "BufFileWrite";
            break;
        case WAIT_EVENT_BUFFILE_TRUNCATE:
            event_name = "BufFileTruncate";
            break;
        case WAIT_EVENT_CONTROL_FILE_READ:
            event_name = "ControlFileRead";
            break;
        case WAIT_EVENT_CONTROL_FILE_SYNC:
            event_name = "ControlFileSync";
            break;
        case WAIT_EVENT_CONTROL_FILE_SYNC_UPDATE:
            event_name = "ControlFileSyncUpdate";
            break;
        case WAIT_EVENT_CONTROL_FILE_WRITE:
            event_name = "ControlFileWrite";
            break;
        case WAIT_EVENT_CONTROL_FILE_WRITE_UPDATE:
            event_name = "ControlFileWriteUpdate";
            break;
        case WAIT_EVENT_COPY_FILE_READ:
            event_name = "CopyFileRead";
            break;
        case WAIT_EVENT_COPY_FILE_WRITE:
            event_name = "CopyFileWrite";
            break;
        case WAIT_EVENT_DATA_FILE_EXTEND:
            event_name = "DataFileExtend";
            break;
        case WAIT_EVENT_DATA_FILE_FLUSH:
            event_name = "DataFileFlush";
            break;
        case WAIT_EVENT_DATA_FILE_IMMEDIATE_SYNC:
            event_name = "DataFileImmediateSync";
            break;
        case WAIT_EVENT_DATA_FILE_PREFETCH:
            event_name = "DataFilePrefetch";
            break;
        case WAIT_EVENT_DATA_FILE_READ:
            event_name = "DataFileRead";
            break;
        case WAIT_EVENT_DATA_FILE_SYNC:
            event_name = "DataFileSync";
            break;
        case WAIT_EVENT_DATA_FILE_TRUNCATE:
            event_name = "DataFileTruncate";
            break;
        case WAIT_EVENT_DATA_FILE_WRITE:
            event_name = "DataFileWrite";
            break;
        case WAIT_EVENT_DSM_ALLOCATE:
            event_name = "DSMAllocate";
            break;
        case WAIT_EVENT_DSM_FILL_ZERO_WRITE:
            event_name = "DSMFillZeroWrite";
            break;
        case WAIT_EVENT_LOCK_FILE_ADDTODATADIR_READ:
            event_name = "LockFileAddToDataDirRead";
            break;
        case WAIT_EVENT_LOCK_FILE_ADDTODATADIR_SYNC:
            event_name = "LockFileAddToDataDirSync";
            break;
        case WAIT_EVENT_LOCK_FILE_ADDTODATADIR_WRITE:
            event_name = "LockFileAddToDataDirWrite";
            break;
        case WAIT_EVENT_LOCK_FILE_CREATE_READ:
            event_name = "LockFileCreateRead";
            break;
        case WAIT_EVENT_LOCK_FILE_CREATE_SYNC:
            event_name = "LockFileCreateSync";
            break;
        case WAIT_EVENT_LOCK_FILE_CREATE_WRITE:
            event_name = "LockFileCreateWrite";
            break;
        case WAIT_EVENT_LOCK_FILE_RECHECKDATADIR_READ:
            event_name = "LockFileReCheckDataDirRead";
            break;
        case WAIT_EVENT_LOGICAL_REWRITE_CHECKPOINT_SYNC:
            event_name = "LogicalRewriteCheckpointSync";
            break;
        case WAIT_EVENT_LOGICAL_REWRITE_MAPPING_SYNC:
            event_name = "LogicalRewriteMappingSync";
            break;
        case WAIT_EVENT_LOGICAL_REWRITE_MAPPING_WRITE:
            event_name = "LogicalRewriteMappingWrite";
            break;
        case WAIT_EVENT_LOGICAL_REWRITE_SYNC:
            event_name = "LogicalRewriteSync";
            break;
        case WAIT_EVENT_LOGICAL_REWRITE_TRUNCATE:
            event_name = "LogicalRewriteTruncate";
            break;
        case WAIT_EVENT_LOGICAL_REWRITE_WRITE:
            event_name = "LogicalRewriteWrite";
            break;
        case WAIT_EVENT_RELATION_MAP_READ:
            event_name = "RelationMapRead";
            break;
        case WAIT_EVENT_RELATION_MAP_REPLACE:
            event_name = "RelationMapReplace";
            break;
        case WAIT_EVENT_RELATION_MAP_WRITE:
            event_name = "RelationMapWrite";
            break;
        case WAIT_EVENT_REORDER_BUFFER_READ:
            event_name = "ReorderBufferRead";
            break;
        case WAIT_EVENT_REORDER_BUFFER_WRITE:
            event_name = "ReorderBufferWrite";
            break;
        case WAIT_EVENT_REORDER_LOGICAL_MAPPING_READ:
            event_name = "ReorderLogicalMappingRead";
            break;
        case WAIT_EVENT_REPLICATION_SLOT_READ:
            event_name = "ReplicationSlotRead";
            break;
        case WAIT_EVENT_REPLICATION_SLOT_RESTORE_SYNC:
            event_name = "ReplicationSlotRestoreSync";
            break;
        case WAIT_EVENT_REPLICATION_SLOT_SYNC:
            event_name = "ReplicationSlotSync";
            break;
        case WAIT_EVENT_REPLICATION_SLOT_WRITE:
            event_name = "ReplicationSlotWrite";
            break;
        case WAIT_EVENT_SLRU_FLUSH_SYNC:
            event_name = "SLRUFlushSync";
            break;
        case WAIT_EVENT_SLRU_READ:
            event_name = "SLRURead";
            break;
        case WAIT_EVENT_SLRU_SYNC:
            event_name = "SLRUSync";
            break;
        case WAIT_EVENT_SLRU_WRITE:
            event_name = "SLRUWrite";
            break;
        case WAIT_EVENT_SNAPBUILD_READ:
            event_name = "SnapbuildRead";
            break;
        case WAIT_EVENT_SNAPBUILD_SYNC:
            event_name = "SnapbuildSync";
            break;
        case WAIT_EVENT_SNAPBUILD_WRITE:
            event_name = "SnapbuildWrite";
            break;
        case WAIT_EVENT_TIMELINE_HISTORY_FILE_SYNC:
            event_name = "TimelineHistoryFileSync";
            break;
        case WAIT_EVENT_TIMELINE_HISTORY_FILE_WRITE:
            event_name = "TimelineHistoryFileWrite";
            break;
        case WAIT_EVENT_TIMELINE_HISTORY_READ:
            event_name = "TimelineHistoryRead";
            break;
        case WAIT_EVENT_TIMELINE_HISTORY_SYNC:
            event_name = "TimelineHistorySync";
            break;
        case WAIT_EVENT_TIMELINE_HISTORY_WRITE:
            event_name = "TimelineHistoryWrite";
            break;
        case WAIT_EVENT_TWOPHASE_FILE_READ:
            event_name = "TwophaseFileRead";
            break;
        case WAIT_EVENT_TWOPHASE_FILE_SYNC:
            event_name = "TwophaseFileSync";
            break;
        case WAIT_EVENT_TWOPHASE_FILE_WRITE:
            event_name = "TwophaseFileWrite";
            break;
        case WAIT_EVENT_VERSION_FILE_WRITE:
            event_name = "VersionFileWrite";
            break;
        case WAIT_EVENT_WALSENDER_TIMELINE_HISTORY_READ:
            event_name = "WALSenderTimelineHistoryRead";
            break;
        case WAIT_EVENT_WAL_BOOTSTRAP_SYNC:
            event_name = "WALBootstrapSync";
            break;
        case WAIT_EVENT_WAL_BOOTSTRAP_WRITE:
            event_name = "WALBootstrapWrite";
            break;
        case WAIT_EVENT_WAL_COPY_READ:
            event_name = "WALCopyRead";
            break;
        case WAIT_EVENT_WAL_COPY_SYNC:
            event_name = "WALCopySync";
            break;
        case WAIT_EVENT_WAL_COPY_WRITE:
            event_name = "WALCopyWrite";
            break;
        case WAIT_EVENT_WAL_INIT_SYNC:
            event_name = "WALInitSync";
            break;
        case WAIT_EVENT_WAL_INIT_WRITE:
            event_name = "WALInitWrite";
            break;
        case WAIT_EVENT_WAL_READ:
            event_name = "WALRead";
            break;
        case WAIT_EVENT_WAL_SYNC:
            event_name = "WALSync";
            break;
        case WAIT_EVENT_WAL_SYNC_METHOD_ASSIGN:
            event_name = "WALSyncMethodAssign";
            break;
        case WAIT_EVENT_WAL_WRITE:
            event_name = "WALWrite";
            break;
 
            /* no default case, so that compiler will warn */
    }
 
    return event_name;
}