Table 2 List of wait events corresponding to lightweight locks

wait_event	Description
ShmemIndexLock	Used to protect the primary index table, a hash table, in shared memory.
OidGenLock	Used to prevent different threads from generating the same OID.
XidGenLock	Used to prevent two transactions from obtaining the same transaction ID.
ProcArrayLock	Used to prevent concurrent access to or concurrent modification on ProcArray shared arrays.
SInvalReadLock	Used to prevent concurrent execution with invalid message deletion.
SInvalWriteLock	Used to prevent concurrent execution with invalid message write and deletion.
WALInsertLock	Used to prevent concurrent execution with WAL insertion.
WALWriteLock	Used to prevent concurrent write from a WAL buffer to a disk.
ControlFileLock	Used to prevent concurrent read/write or concurrent write/write on the pg_control file.
CheckpointLock	Used to prevent multi-checkpoint concurrent execution.
CLogControlLock	Used to prevent concurrent access to or concurrent modification on the Clog control data structure.
SubtransControlLock	Used to prevent concurrent access to or concurrent modification on the subtransaction control data structure.
MultiXactGenLock	Used to allocate a unique MultiXact ID in serial mode.
MultiXactOffsetControlLock	Used to prevent concurrent read/write or concurrent write/write on pg_multixact/offset.
MultiXactMemberControlLock	Used to prevent concurrent read/write or concurrent write/write on pg_multixact/members.
RelCacheInitLock	Used to add a lock before any operations are performed on the init file when messages are invalid.
CheckpointerCommLock	Used to send file flush requests to a checkpointer. The request structure needs to be inserted to a request queue in serial mode.
TwoPhaseStateLock	Used to prevent concurrent access to or modification on two-phase information sharing arrays.
TablespaceCreateLock	Used to check whether a tablespace already exists.
BtreeVacuumLock	Used to prevent VACUUM from clearing pages that are being used by B-tree indexes.
AutovacuumLock	Used to access the autovacuum worker array in serial mode.
AutovacuumScheduleLock	Used to distribute tables requiring VACUUM in serial mode.
AutoanalyzeLock	Used to obtain and release resources related to a task that allows for autoanalyze execution.
SyncScanLock	Used to determine the start position of a relfilenode during heap scanning.
NodeTableLock	Used to protect a shared structure that stores database node information.
PoolerLock	Used to prevent two threads from simultaneously obtaining the same connection from a connection pool.
RelationMappingLock	Used to wait for the mapping file between system catalogs and storage locations to be updated.
AsyncCtlLock	Used to prevent concurrent access to or concurrent modification on the sharing notification status.
AsyncQueueLock	Used to prevent concurrent access to or concurrent modification on the sharing notification queue.
SerializableXactHashLock	Used to prevent concurrent read/write or concurrent write/write on a sharing structure for serializable transactions.
SerializableFinishedListLock	Used to prevent concurrent read/write or concurrent write/write on a shared linked list for completed serial transactions.
SerializablePredicateLockListLock	Used to protect a linked list of serializable transactions that have locks.
OldSerXidLock	Used to protect a structure that records serializable transactions that have conflicts.
FileStatLock	Used to protect a data structure that stores statistics file information.
SyncRepLock	Used to protect Xlog synchronization information during primary/standby replication.
DataSyncRepLock	Used to protect data page synchronization information during primary/standby replication.
CStoreColspaceCacheLock	Used to add a lock when CU space is allocated for a column-store table.
CStoreCUCacheSweepLock	Used to add a lock when CU caches used by a column-store table are cyclically washed out.
MetaCacheSweepLock	Used to add a lock when metadata is cyclically washed out.
ExtensionConnectorLibLock	Adds a lock when a specific dynamic library is loaded or uninstalled in ODBC connection initialization scenarios.
SearchServerLibLock	Used to add a lock on the file read operation when a specific dynamic library is initially loaded in GPU-accelerated scenarios.
LsnXlogChkFileLock	Used to serially update the Xlog flush points for primary and standby servers recorded in a specific structure.
ReplicationSlotAllocationLock	Used to add a lock when a primary server allocates stream replication slots during primary/standby replication.
ReplicationSlotControlLock	Used to prevent concurrent update of stream replication slot status during primary/standby replication.
ResourcePoolHashLock	Used to prevent concurrent access to or concurrent modification on a resource pool table, a hash table.
WorkloadStatHashLock	Used to prevent concurrent access to or concurrent modification on a hash table that contains SQL requests from the primary node of the database side.
WorkloadIoStatHashLock	Used to prevent concurrent access to or concurrent modification on a hash table that contains I/O information of the current database node.
WorkloadCGroupHashLock	Used to prevent concurrent access to or concurrent modification on a hash table that contains Cgroup information.
OBSGetPathLock	Used to prevent concurrent read/write or concurrent write/write on an OBS path.
WorkloadUserInfoLock	Used to prevent concurrent access to or concurrent modification on a hash table that contains user information about load management.
WorkloadRecordLock	Used to prevent concurrent access to or concurrent modification on a hash table that contains requests received by the primary node of the databases during adaptive memory management.
WorkloadIOUtilLock	Used to protect a structure that records iostat and CPU load information.
WorkloadNodeGroupLock	Used to prevent concurrent access to or concurrent modification on a hash table that contains node group information in memory.
JobShmemLock	Used to protect global variables in the shared memory that is periodically read during a scheduled task.
OBSRuntimeLock	Used to obtain environment variables, for example, GASSHOME.
LLVMDumpIRLock	Used to export the assembly language for dynamically generating functions.
LLVMParseIRLock	Used to compile and parse a finished IR function from the IR file at the start position of a query.
CriticalCacheBuildLock	Used to load caches from a shared or local cache initialization file.
WaitCountHashLock	Used to protect a shared structure in user statement counting scenarios.
BufMappingLock	Used to protect operations on a shared-buffer mapping table.
LockMgrLock	Used to protect the information about a common lock structure.
PredicateLockMgrLock	Used to protect the information about a lock structure that has serializable transactions.
OperatorRealTLock	Used to prevent concurrent access to or concurrent modification on a global structure that contains real-time data at the operator level.
OperatorHistLock	Used to prevent concurrent access to or concurrent modification on a global structure that contains historical data at the operator level.
SessionRealTLock	Used to prevent concurrent access to or concurrent modification on a global structure that contains real-time data at the query level.
SessionHistLock	Used to prevent concurrent access to or concurrent modification on a global structure that contains historical data at the query level.
CacheSlotMappingLock	Used to protect global CU cache information.
BarrierLock	Used to ensure that only one thread is creating a barrier at a time.
dummyServerInfoCacheLock	Used to protect a global hash table where the information about MogDB connections is cached.
RPNumberLock	Used by a database node on a computing MogDB to count the number of threads for a task where plans are being executed.
ClusterRPLock	Used to control concurrent access on MogDB load data maintained in a CCN of MogDB.
CBMParseXlogLock	Used to protect the lock used when CBM parses Xlogs.
RelfilenodeReuseLock	Used to prevent the link to a reused column attribute file from being canceled by mistake.
RcvWriteLock	Used to prevent concurrent call of WalDataRcvWrite.
PercentileLock	Used to protect global percentile buffers.
CSNBufMappingLock	Used to protect CSN pages.
UniqueSQLMappingLock	Used to protect a unique SQL hash table.
DelayDDLLock	Used to prevent concurrent DDL operations.
CLOG Ctl	Used to prevent concurrent access to or concurrent modification on the Clog control data structure.
Async Ctl	Used to protect asynchronization buffers.
MultiXactOffset Ctl	Used to protect SLRU buffers of a MultiXact offset.
MultiXactMember Ctl	Used to protect SLRU buffer of a MultiXact member.
OldSerXid SLRU Ctl	Used to protect SLRU buffers of old transaction IDs.
ReplicationSlotLock	Used to protect a replication slot.
PGPROCLock	Used to protect the PGPROC structure.
MetaCacheLock	Used to protect meta caches.
DataCacheLock	Used to protect data caches.
InstrUserLock	Used to protect a user hash table.
BadBlockStatHashLock	Used to protect the hash table global_bad_block_stat
BufFreelistLock	Used to ensure the atomicity of free list operations in the shared buffer.
CUSlotListLock	Used to control concurrent operations on the slot of the column-store buffer.
AddinShmemInitLock	Used to protect the initialization of the shared memory object.
AlterPortLock	Used to protect the coordinator node from changing the registration port number.
FdwPartitionCaheLock	Management lock of the buffer of the HDFS partitioned table.
DfsConnectorCacheLock	Management lock of the DFSConnector buffer.
DfsSpaceCacheLock	Management lock of the HDFS tablespace management buffer.
FullBuildXlogCopyStartPtrLock	Used to protect Xlog copy operations in the full build.
DfsUserLoginLock	Used for HDFS user login and authentication.
LogicalReplicationSlotPersistentDataLock	Used to protect data in the replication slot during logical replication.
WorkloadSessionInfoLock	Used to protect the access to the session info memory hash table of the load management module.
InstrWorkloadLock	Used to protect the access to the memory hash table that stores load management statistics.
PgfdwLock	Used by the management instance to establish a connection to the foreign server.
InstanceTimeLock	Used to obtain time information of sessions in an instance.
XlogRemoveSegLock	Used to protect Xlog segment file recycling.
DnUsedSpaceHashLock	Used to update space usage information corresponding to a session.
CsnMinLock	Used to calculate CSNmin.
GPCCommitLock	Used to protect the addition of the global Plan Cache hash table.
GPCClearLock	Used to protect the clearing of the global plan cache hash table.
GPCTimelineLock	Used to protect the timeline check of the global plan cache hash table.
TsTagsCacheLock	Used to manage the time series tag cache.
InstanceRealTLock	Used to protect the update of the hash table that stores shared instance statistics.
CLogBufMappingLock	Used to manage the cache of commit logs.
GPCMappingLock	Used to manage the global plan cache.
GPCPrepareMappingLock	Used to manage the global plan cache.
BufferIOLock	Used to protect I/O operations on pages in the shared buffer.
BufferContentLock	Used to protect the read and modification of the page content in the shared buffer.
CSNLOG Ctl	Used for CSN log management.
DoubleWriteLock	Used to manage doublewrite operations.
RowPageReplicationLock	Used to manage data page replication of row-store.
extension	Other lightweight locks