number of background workers that the planner will consider using is limited to at most max_paral- lel_workers_per_gather. The total number of background workers that can exist at any one time is limited performance. If this occurrence is frequent, consider increasing max_worker_processes and max_paral- lel_workers so that more workers can be run simultaneously or alternatively reducing max_par- allel_workers_per_gather Also, unlike a regular Append node, which can only have partial children when used within a paral- lel plan, a Parallel Append node can have both partial and non-partial child plans. Non-partial children

number of background workers that the planner will consider using is limited to at most max_paral- lel_workers_per_gather. The total number of background workers that can exist at any one time is limited performance. If this occurrence is frequent, consider increasing max_worker_processes and max_paral- lel_workers so that more workers can be run simultaneously or alternatively reducing max_par- allel_workers_per_gather Also, unlike a regular Append node, which can only have partial children when used within a paral- lel plan, a Parallel Append node can have both partial and non-partial child plans. Non-partial children

number of background workers that the planner will consider using is limited to at most max_paral- lel_workers_per_gather. The total number of background workers that can exist at any one time is limited performance. If this occurrence is frequent, consider increasing max_worker_processes and max_paral- lel_workers so that more workers can be run simultaneously or alternatively reducing max_par- allel_workers_per_gather Also, unlike a regular Append node, which can only have partial children when used within a paral- lel plan, a Parallel Append node can have both partial and non-partial child plans. Non-partial children

number of background workers that the planner will consider using is limited to at most max_paral- lel_workers_per_gather. The total number of background workers that can exist at any one time is limited performance. If this occurrence is frequent, consider increasing max_worker_processes and max_paral- lel_workers so that more workers can be run simultaneously or alternatively reducing max_par- allel_workers_per_gather Also, unlike a regular Append node, which can only have partial children when used within a paral- lel plan, a Parallel Append node can have both partial and non-partial child plans. Non-partial children

number of background workers that the planner will consider using is limited to at most max_paral- lel_workers_per_gather. The total number of background workers that can exist at any one time is limited performance. If this occurrence is frequent, consider increasing max_worker_processes and max_paral- lel_workers so that more workers can be run simultaneously or alternatively reducing max_par- allel_workers_per_gather Also, unlike a regular Append node, which can only have partial children when used within a paral- lel plan, a Parallel Append node can have both partial and non-partial child plans. Non-partial children

number of background workers that the planner will consider using is limited to at most max_paral- lel_workers_per_gather. The total number of background workers that can exist at any one time is limited performance. If this occurrence is frequent, consider increasing max_worker_processes and max_paral- lel_workers so that more workers can be run simultaneously or alternatively reducing max_par- allel_workers_per_gather Also, unlike a regular Append node, which can only have partial children when used within a paral- lel plan, a Parallel Append node can have both partial and non-partial child plans. Non-partial children

number of background workers that the planner will consider using is limited to at most max_paral- lel_workers_per_gather. The total number of background workers that can exist at any one time is limited performance. If this occurrence is frequent, consider increasing max_worker_processes and max_paral- lel_workers so that more workers can be run simultaneously or alternatively reducing max_par- allel_workers_per_gather Also, unlike a regular Append node, which can only have partial children when used within a paral- lel plan, a Parallel Append node can have both partial and non-partial child plans. Non-partial children

type no %p Process ID no %P Process ID of the parallel group leader, if this process is a paral- lel query worker no %t Time stamp without millisec- onds no %m Time stamp with milliseconds no %n parallel bitmap index scan. SharedTupleStore Waiting to access a shared tuple store during paral- lel query. ShmemIndex Waiting to find or allocate space in shared memo- ry. SInvalRead Waiting to retrieve pg_lsn Last write-ahead log location received, the initial value of this field being 0; NULL for paral- lel apply workers last_msg_send_time timestamp with time zone Send time of last message received from

type no %p Process ID no %P Process ID of the parallel group leader, if this process is a paral- lel query worker no %t Time stamp without millisec- onds no %m Time stamp with milliseconds no %n parallel bitmap index scan. SharedTupleStore Waiting to access a shared tuple store during paral- lel query. 879 Monitoring Database Activity LWLock Wait Event Description ShmemIndex Waiting to find pg_lsn Last write-ahead log location received, the initial value of this field being 0; NULL for paral- lel apply workers last_msg_send_time timestamp with time zone Send time of last message received from

TiDB Light- ning auto- mati- cally exits with an error if the tar- get table is not empty. If paral- lel im- port mode is en- abled (parallel �→ - �→ import �→ �→ = �→ �→ true �→ ), this check item will be FILE �→ CSV Splits a sin- gle CSV file into mul- tiple smaller chunks of around 256 MiB for paral- lel pro- cess- ing to im- prove im- port effi- ciency. This pa- rame- ter only works for non- compressed Controls whether TiDB sup- ports disk spill for the paral- lel HashAgg algo- rithm. When it is ON, disk spill can be trig- gered for the paral- lel HashAgg algo- rithm. This vari- able will be depre- cated