Extend PgStat_HashKey.objid from 4 to 8 bytes

This opens the possibility to define keys for more types of statistics
kinds in PgStat_HashKey, the first case being 8-byte query IDs for
statistics like pg_stat_statements.

This increases the size of PgStat_HashKey from 12 to 16 bytes, while
PgStatShared_HashEntry, entry stored in the dshash for pgstats, keeps
the same size due to alignment.

xl_xact_stats_item, that tracks the stats items to drop in commit WAL
records, is increased from 12 to 16 bytes.  Note that individual chunks
in commit WAL records should be multiples of sizeof(int), hence 8-byte
object IDs are stored as two uint32, based on a suggestion from Heikki
Linnakangas.

While on it, the field of PgStat_HashKey is renamed from "objoid" to
"objid", as for some stats kinds this field does not refer to OIDs but
just IDs, like for replication slot stats.

This commit bumps the following format variables:
- PGSTAT_FILE_FORMAT_ID, as PgStat_HashKey is written to the stats file
for non-serialized stats kinds in the dshash table.
- XLOG_PAGE_MAGIC for the changes in xl_xact_stats_item.
- Catalog version, for the SQL function pg_stat_have_stats().

Reviewed-by: Bertrand Drouvot
Discussion: https://postgr.es/m/ZsvTS9EW79Up8I62@paquier.xyz

1 files changed, 3 insertions, 3 deletions

diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index be2c91168a1..4752dfe7197 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -267,7 +267,7 @@ typedef struct PgStat_TableXactStatus
  * ------------------------------------------------------------
  */
 
-#define PGSTAT_FILE_FORMAT_ID	0x01A5BCAE
+#define PGSTAT_FILE_FORMAT_ID	0x01A5BCAF
 
 typedef struct PgStat_ArchiverStats
 {
@@ -511,7 +511,7 @@ extern long pgstat_report_stat(bool force);
 extern void pgstat_force_next_flush(void);
 
 extern void pgstat_reset_counters(void);
-extern void pgstat_reset(PgStat_Kind kind, Oid dboid, Oid objoid);
+extern void pgstat_reset(PgStat_Kind kind, Oid dboid, uint64 objid);
 extern void pgstat_reset_of_kind(PgStat_Kind kind);
 
 /* stats accessors */
@@ -520,7 +520,7 @@ extern TimestampTz pgstat_get_stat_snapshot_timestamp(bool *have_snapshot);
 
 /* helpers */
 extern PgStat_Kind pgstat_get_kind_from_str(char *kind_str);
-extern bool pgstat_have_entry(PgStat_Kind kind, Oid dboid, Oid objoid);
+extern bool pgstat_have_entry(PgStat_Kind kind, Oid dboid, uint64 objid);
 
 
 /*