diff options
Diffstat (limited to 'src/include/utils')
| -rw-r--r-- | src/include/utils/pgstat_internal.h | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h index 4b65dfef7d4..efe5dfc2321 100644 --- a/src/include/utils/pgstat_internal.h +++ b/src/include/utils/pgstat_internal.h @@ -94,6 +94,19 @@ typedef struct PgStatShared_HashEntry pg_atomic_uint32 refcount; /* + * Counter tracking the number of times the entry has been reused. + * + * Set to 0 when the entry is created, and incremented by one each time + * the shared entry is reinitialized with pgstat_reinit_entry(). + * + * May only be incremented / decremented while holding at least a shared + * lock on the dshash partition containing the entry. Like refcount, it + * needs to be an atomic variable because multiple backends can increment + * the generation with just a shared lock. + */ + pg_atomic_uint32 generation; + + /* * Pointer to shared stats. The stats entry always starts with * PgStatShared_Common, embedded in a larger struct containing the * PgStat_Kind specific stats fields. @@ -133,6 +146,12 @@ typedef struct PgStat_EntryRef PgStatShared_Common *shared_stats; /* + * Copy of PgStatShared_HashEntry->generation, keeping locally track of + * the shared stats entry "generation" retrieved (number of times reused). + */ + uint32 generation; + + /* * Pending statistics data that will need to be flushed to shared memory * stats eventually. Each stats kind utilizing pending data defines what * format its pending data has and needs to provide a |