diff options
Diffstat (limited to 'src/include/utils/pgstat_internal.h')
| -rw-r--r-- | src/include/utils/pgstat_internal.h | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h index 6cf00008f63..bf75ebcef31 100644 --- a/src/include/utils/pgstat_internal.h +++ b/src/include/utils/pgstat_internal.h @@ -48,7 +48,13 @@ * PgStatShared_Common as the first element. */ -/* struct for shared statistics hash entry key. */ +/* + * Struct for shared statistics hash entry key. + * + * NB: We assume that this struct contains no padding. Also, 8 bytes + * allocated for the object ID are good enough to ensure the uniqueness + * of the hash key, hence the addition of new fields is not recommended. + */ typedef struct PgStat_HashKey { PgStat_Kind kind; /* statistics entry kind */ @@ -58,6 +64,15 @@ typedef struct PgStat_HashKey } PgStat_HashKey; /* + * PgStat_HashKey should not have any padding. Checking that the structure + * size matches with the sum of each field is a check simple enough to + * enforce this policy. + */ +StaticAssertDecl((sizeof(PgStat_Kind) + sizeof(uint64) + sizeof(Oid)) == + sizeof(PgStat_HashKey), + "PgStat_HashKey should have no padding"); + +/* * Shared statistics hash entry. Doesn't itself contain any stats, but points * to them (with ->body). That allows the stats entries themselves to be of * variable size. |