RE: Speed up transaction completion faster after many relations are accessed in a transaction

From: David Rowley [mailto:david(dot)rowley(at)2ndquadrant(dot)com]
> I've revised the patch to add a new constant named
> LOCKMETHODLOCALHASH_SHRINK_SIZE. I've set this to 64 for now. Once the hash

Thank you, and good performance. The patch passed make check.

I'm OK with the current patch, but I have a few comments. Please take them as you see fit (I wouldn't mind if you don't.)

(1)
+#define LOCKMETHODLOCALHASH_SHRINK_SIZE 64

How about LOCKMETHODLOCALHASH_SHRINK_THRESHOLD, because this determines the threshold value to trigger shrinkage? Code in PostgreSQL seems to use the term threshold.

(2)
+/* Complain if the above are not set to something sane */
+#if LOCKMETHODLOCALHASH_SHRINK_SIZE < LOCKMETHODLOCALHASH_INIT_SIZE
+#error "invalid LOCKMETHODLOCALHASH_SHRINK_SIZE"
+#endif

I don't think these are necessary, because these are fixed and not configurable. FYI, src/include/utils/memutils.h doesn't have #error to test these macros.

#define ALLOCSET_DEFAULT_MINSIZE 0
#define ALLOCSET_DEFAULT_INITSIZE (8 * 1024)
#define ALLOCSET_DEFAULT_MAXSIZE (8 * 1024 * 1024)

(3)
+ if (hash_get_num_entries(LockMethodLocalHash) == 0 &&
+ hash_get_max_bucket(LockMethodLocalHash) >
+ LOCKMETHODLOCALHASH_SHRINK_SIZE)
+ CreateLocalLockHash();

I get an impression that Create just creates something where there's nothing. How about Init or Recreate?

Regards
Takayuki Tsunakawa