Consume fewer XIDs when restarting primary

libs/postgres_ffi/src/xlog_utils.rs

@@ -55,7 +55,7 @@ pub const SIZE_OF_XLOG_RECORD_DATA_HEADER_SHORT: usize = 1 * 2;
 /// metadata checkpoint only once per XID_CHECKPOINT_INTERVAL transactions.
 /// XID_CHECKPOINT_INTERVAL should not be larger than BLCKSZ*CLOG_XACTS_PER_BYTE
 /// in order to let CLOG_TRUNCATE mechanism correctly extend CLOG.
-const XID_CHECKPOINT_INTERVAL: u32 = 1024;
+const XID_CHECKPOINT_INTERVAL: u32 = 128;
 
 pub fn XLogSegmentsPerXLogId(wal_segsz_bytes: usize) -> XLogSegNo {
     (0x100000000u64 / wal_segsz_bytes as u64) as XLogSegNo

libs/postgres_ffi/wal_craft/src/xlog_utils_test.rs

@@ -187,19 +187,19 @@ pub fn test_update_next_xid() {
     // The input XID gets rounded up to the next XID_CHECKPOINT_INTERVAL
     // boundary
     checkpoint.update_next_xid(100);
-    assert_eq!(checkpoint.nextXid.value, 1024);
+    assert_eq!(checkpoint.nextXid.value, 128);
 
     // No change
-    checkpoint.update_next_xid(500);
-    assert_eq!(checkpoint.nextXid.value, 1024);
-    checkpoint.update_next_xid(1023);
-    assert_eq!(checkpoint.nextXid.value, 1024);
+    checkpoint.update_next_xid(100);
+    assert_eq!(checkpoint.nextXid.value, 128);
+    checkpoint.update_next_xid(127);
+    assert_eq!(checkpoint.nextXid.value, 128);
 
     // The function returns the *next* XID, given the highest XID seen so
-    // far. So when we pass 1024, the nextXid gets bumped up to the next
+    // far. So when we pass 128, the nextXid gets bumped up to the next
     // XID_CHECKPOINT_INTERVAL boundary.
-    checkpoint.update_next_xid(1024);
-    assert_eq!(checkpoint.nextXid.value, 2048);
+    checkpoint.update_next_xid(128);
+    assert_eq!(checkpoint.nextXid.value, 256);
 }
 
 #[test]