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Activity
- The server process is idle. This is used by
- system processes waiting for activity in their main processing loop.
- wait_event will identify the specific wait point.
- See .
+ The server process is idle. This event type indicates a process
+ waiting for activity in its main processing loop.
+ wait_event will identify the specific wait point;
+ see .
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BufferPin
- The server process is waiting to access to
- a data buffer during a period when no other process can be
- examining that buffer. Buffer pin waits can be protracted if
- another process holds an open cursor which last read data from the
+ The server process is waiting for exclusive access to
+ a data buffer. Buffer pin waits can be protracted if
+ another process holds an open cursor that last read data from the
buffer in question. See .
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Client
- The server process is waiting for some activity
- on a socket from user applications, and that the server expects
- something to happen that is independent from its internal processes.
- wait_event will identify the specific wait point.
- See .
+ The server process is waiting for activity on a socket
+ connected to a user application. Thus, the server expects something
+ to happen that is independent of its internal processes.
+ wait_event will identify the specific wait point;
+ see .
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Extension
- The server process is waiting for activity
- in an extension module. This category is useful for modules to
- track custom waiting points.
+ The server process is waiting for some condition defined by an
+ extension module.
See .
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IO
- The server process is waiting for a IO to complete.
- wait_event will identify the specific wait point.
- See .
+ The server process is waiting for an I/O operation to complete.
+ wait_event will identify the specific wait point;
+ see .
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IPC
- The server process is waiting for some activity
- from another process in the server. wait_event will
- identify the specific wait point.
- See .
+ The server process is waiting for some interaction with
+ another server process. wait_event will
+ identify the specific wait point;
+ see .
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Lock
- The backend is waiting for a heavyweight lock.
+ The server process is waiting for a heavyweight lock.
Heavyweight locks, also known as lock manager locks or simply locks,
primarily protect SQL-visible objects such as tables. However,
they are also used to ensure mutual exclusion for certain internal
operations such as relation extension. wait_event
- will identify the type of lock awaited.
- See .
+ will identify the type of lock awaited;
+ see .
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LWLock
- The backend is waiting for a lightweight lock.
- Each such lock protects a particular data structure in shared memory.
+ The server process is waiting for a lightweight lock.
+ Most such locks protect a particular data structure in shared memory.
wait_event will contain a name identifying the purpose
of the lightweight lock. (Some locks have specific names; others
are part of a group of locks each with a similar purpose.)
Timeout
The server process is waiting for a timeout
to expire. wait_event will identify the specific wait
- point. See .
+ point; see .