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Diffstat (limited to 'src/include/storage/sinval.h')
| -rw-r--r-- | src/include/storage/sinval.h | 153 |
1 files changed, 153 insertions, 0 deletions
diff --git a/src/include/storage/sinval.h b/src/include/storage/sinval.h new file mode 100644 index 0000000..903818b --- /dev/null +++ b/src/include/storage/sinval.h @@ -0,0 +1,153 @@ +/*------------------------------------------------------------------------- + * + * sinval.h + * POSTGRES shared cache invalidation communication definitions. + * + * + * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * src/include/storage/sinval.h + * + *------------------------------------------------------------------------- + */ +#ifndef SINVAL_H +#define SINVAL_H + +#include <signal.h> + +#include "storage/relfilenode.h" + +/* + * We support several types of shared-invalidation messages: + * * invalidate a specific tuple in a specific catcache + * * invalidate all catcache entries from a given system catalog + * * invalidate a relcache entry for a specific logical relation + * * invalidate all relcache entries + * * invalidate an smgr cache entry for a specific physical relation + * * invalidate the mapped-relation mapping for a given database + * * invalidate any saved snapshot that might be used to scan a given relation + * More types could be added if needed. The message type is identified by + * the first "int8" field of the message struct. Zero or positive means a + * specific-catcache inval message (and also serves as the catcache ID field). + * Negative values identify the other message types, as per codes below. + * + * Catcache inval events are initially driven by detecting tuple inserts, + * updates and deletions in system catalogs (see CacheInvalidateHeapTuple). + * An update can generate two inval events, one for the old tuple and one for + * the new, but this is reduced to one event if the tuple's hash key doesn't + * change. Note that the inval events themselves don't actually say whether + * the tuple is being inserted or deleted. Also, since we transmit only a + * hash key, there is a small risk of unnecessary invalidations due to chance + * matches of hash keys. + * + * Note that some system catalogs have multiple caches on them (with different + * indexes). On detecting a tuple invalidation in such a catalog, separate + * catcache inval messages must be generated for each of its caches, since + * the hash keys will generally be different. + * + * Catcache, relcache, and snapshot invalidations are transactional, and so + * are sent to other backends upon commit. Internally to the generating + * backend, they are also processed at CommandCounterIncrement so that later + * commands in the same transaction see the new state. The generating backend + * also has to process them at abort, to flush out any cache state it's loaded + * from no-longer-valid entries. + * + * smgr and relation mapping invalidations are non-transactional: they are + * sent immediately when the underlying file change is made. + */ + +typedef struct +{ + int8 id; /* cache ID --- must be first */ + Oid dbId; /* database ID, or 0 if a shared relation */ + uint32 hashValue; /* hash value of key for this catcache */ +} SharedInvalCatcacheMsg; + +#define SHAREDINVALCATALOG_ID (-1) + +typedef struct +{ + int8 id; /* type field --- must be first */ + Oid dbId; /* database ID, or 0 if a shared catalog */ + Oid catId; /* ID of catalog whose contents are invalid */ +} SharedInvalCatalogMsg; + +#define SHAREDINVALRELCACHE_ID (-2) + +typedef struct +{ + int8 id; /* type field --- must be first */ + Oid dbId; /* database ID, or 0 if a shared relation */ + Oid relId; /* relation ID, or 0 if whole relcache */ +} SharedInvalRelcacheMsg; + +#define SHAREDINVALSMGR_ID (-3) + +typedef struct +{ + /* note: field layout chosen to pack into 16 bytes */ + int8 id; /* type field --- must be first */ + int8 backend_hi; /* high bits of backend ID, if temprel */ + uint16 backend_lo; /* low bits of backend ID, if temprel */ + RelFileNode rnode; /* spcNode, dbNode, relNode */ +} SharedInvalSmgrMsg; + +#define SHAREDINVALRELMAP_ID (-4) + +typedef struct +{ + int8 id; /* type field --- must be first */ + Oid dbId; /* database ID, or 0 for shared catalogs */ +} SharedInvalRelmapMsg; + +#define SHAREDINVALSNAPSHOT_ID (-5) + +typedef struct +{ + int8 id; /* type field --- must be first */ + Oid dbId; /* database ID, or 0 if a shared relation */ + Oid relId; /* relation ID */ +} SharedInvalSnapshotMsg; + +typedef union +{ + int8 id; /* type field --- must be first */ + SharedInvalCatcacheMsg cc; + SharedInvalCatalogMsg cat; + SharedInvalRelcacheMsg rc; + SharedInvalSmgrMsg sm; + SharedInvalRelmapMsg rm; + SharedInvalSnapshotMsg sn; +} SharedInvalidationMessage; + + +/* Counter of messages processed; don't worry about overflow. */ +extern uint64 SharedInvalidMessageCounter; + +extern volatile sig_atomic_t catchupInterruptPending; + +extern void SendSharedInvalidMessages(const SharedInvalidationMessage *msgs, + int n); +extern void ReceiveSharedInvalidMessages(void (*invalFunction) (SharedInvalidationMessage *msg), + void (*resetFunction) (void)); + +/* signal handler for catchup events (PROCSIG_CATCHUP_INTERRUPT) */ +extern void HandleCatchupInterrupt(void); + +/* + * enable/disable processing of catchup events directly from signal handler. + * The enable routine first performs processing of any catchup events that + * have occurred since the last disable. + */ +extern void ProcessCatchupInterrupt(void); + +extern int xactGetCommittedInvalidationMessages(SharedInvalidationMessage **msgs, + bool *RelcacheInitFileInval); +extern void ProcessCommittedInvalidationMessages(SharedInvalidationMessage *msgs, + int nmsgs, bool RelcacheInitFileInval, + Oid dbid, Oid tsid); + +extern void LocalExecuteInvalidationMessage(SharedInvalidationMessage *msg); + +#endif /* SINVAL_H */ |