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| author | Andres Freund <andres@anarazel.de> | 2015-01-14 18:45:22 +0100 |
|---|---|---|
| committer | Andres Freund <andres@anarazel.de> | 2015-01-14 18:45:22 +0100 |
| commit | 59f71a0d0b56b2df48db4bf1738aece5551f7a47 (patch) | |
| tree | 6023eb572eade66adb21ee0ae84fd6aa33e30ac9 /src/include | |
| parent | 85a2a8903f7e9151793308d0638621003aded5ae (diff) | |
| download | postgresql-59f71a0d0b56b2df48db4bf1738aece5551f7a47.tar.gz postgresql-59f71a0d0b56b2df48db4bf1738aece5551f7a47.zip | |
Add a default local latch for use in signal handlers.
To do so, move InitializeLatchSupport() into the new common process
initialization functions, and add a new global variable MyLatch.
MyLatch is usable as soon InitPostmasterChild() has been called
(i.e. very early during startup). Initially it points to a process
local latch that exists in all processes. InitProcess/InitAuxiliaryProcess
then replaces that local latch with PGPROC->procLatch. During shutdown
the reverse happens.
This is primarily advantageous for two reasons: For one it simplifies
dealing with the shared process latch, especially in signal handlers,
because instead of having to check for MyProc, MyLatch can be used
unconditionally. For another, a later patch that makes FEs/BE
communication use latches, now can rely on the existence of a latch,
even before having gone through InitProcess.
Discussion: 20140927191243.GD5423@alap3.anarazel.de
Diffstat (limited to 'src/include')
| -rw-r--r-- | src/include/miscadmin.h | 4 | ||||
| -rw-r--r-- | src/include/storage/latch.h | 2 |
2 files changed, 5 insertions, 1 deletions
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h index b94a94499b7..6e33a172122 100644 --- a/src/include/miscadmin.h +++ b/src/include/miscadmin.h @@ -148,6 +148,7 @@ extern int max_worker_processes; extern PGDLLIMPORT int MyProcPid; extern PGDLLIMPORT pg_time_t MyStartTime; extern PGDLLIMPORT struct Port *MyProcPort; +extern PGDLLIMPORT struct Latch *MyLatch; extern long MyCancelKey; extern int MyPMChildSlot; @@ -302,6 +303,9 @@ extern void SetCurrentRoleId(Oid roleid, bool is_superuser); extern void SetDataDir(const char *dir); extern void ChangeToDataDir(void); +extern void SwitchToSharedLatch(void); +extern void SwitchBackToLocalLatch(void); + /* in utils/misc/superuser.c */ extern bool superuser(void); /* current user is superuser */ extern bool superuser_arg(Oid roleid); /* given user is superuser */ diff --git a/src/include/storage/latch.h b/src/include/storage/latch.h index f1577b00955..28fc684d240 100644 --- a/src/include/storage/latch.h +++ b/src/include/storage/latch.h @@ -85,7 +85,7 @@ * the public functions. It is defined here to allow embedding Latches as * part of bigger structs. */ -typedef struct +typedef struct Latch { sig_atomic_t is_set; bool is_shared; |