From: Junio C Hamano <gitster@pobox.com>
Date: Tue, 27 Feb 2024 02:10:24 +0000 (-0800)
Subject: Merge branch 'ps/reftable-iteration-perf'
X-Git-Tag: v2.45.0-rc0~173
X-Git-Url: http://git.ipfire.org/?p=thirdparty%2Fgit.git;a=commitdiff_plain;h=9f67cbd0a7725857d219da6720fc9a5acfda2960

Merge branch 'ps/reftable-iteration-perf'

The code to iterate over refs with the reftable backend has seen
some optimization.

* ps/reftable-iteration-perf:
  reftable/reader: add comments to `table_iter_next()`
  reftable/record: don't try to reallocate ref record name
  reftable/block: swap buffers instead of copying
  reftable/pq: allocation-less comparison of entry keys
  reftable/merged: skip comparison for records of the same subiter
  reftable/merged: allocation-less dropping of shadowed records
  reftable/record: introduce function to compare records by key
---

9f67cbd0a7725857d219da6720fc9a5acfda2960
diff --cc reftable/merged.c
index a0f222e07b,0f74a14a77..1aa6cd31b7
--- a/reftable/merged.c
+++ b/reftable/merged.c
@@@ -44,13 -45,12 +44,11 @@@ static int merged_iter_init(struct merg
  static void merged_iter_close(void *p)
  {
  	struct merged_iter *mi = p;
 -	int i = 0;
 +
  	merged_iter_pqueue_release(&mi->pq);
 -	for (i = 0; i < mi->stack_len; i++) {
 +	for (size_t i = 0; i < mi->stack_len; i++)
  		reftable_iterator_destroy(&mi->stack[i]);
 -	}
  	reftable_free(mi->stack);
- 	strbuf_release(&mi->key);
- 	strbuf_release(&mi->entry_key);
  }
  
  static int merged_iter_advance_nonnull_subiter(struct merged_iter *mi,
@@@ -243,34 -248,42 +246,32 @@@ static int merged_table_seek_record(str
  		.typ = reftable_record_type(rec),
  		.hash_id = mt->hash_id,
  		.suppress_deletions = mt->suppress_deletions,
- 		.key = STRBUF_INIT,
- 		.entry_key = STRBUF_INIT,
  	};
 -	int n = 0;
 -	int err = 0;
 -	int i = 0;
 -	for (i = 0; i < mt->stack_len && err == 0; i++) {
 -		int e = reftable_table_seek_record(&mt->stack[i], &iters[n],
 -						   rec);
 -		if (e < 0) {
 -			err = e;
 -		}
 -		if (e == 0) {
 -			n++;
 -		}
 -	}
 -	if (err < 0) {
 -		int i = 0;
 -		for (i = 0; i < n; i++) {
 -			reftable_iterator_destroy(&iters[i]);
 -		}
 -		reftable_free(iters);
 -		return err;
 +	struct merged_iter *p;
 +	int err;
 +
 +	REFTABLE_CALLOC_ARRAY(merged.stack, mt->stack_len);
 +	for (size_t i = 0; i < mt->stack_len; i++) {
 +		err = reftable_table_seek_record(&mt->stack[i],
 +						 &merged.stack[merged.stack_len], rec);
 +		if (err < 0)
 +			goto out;
 +		if (!err)
 +			merged.stack_len++;
  	}
  
 -	merged.stack_len = n;
  	err = merged_iter_init(&merged);
 -	if (err < 0) {
 +	if (err < 0)
 +		goto out;
 +
 +	p = reftable_malloc(sizeof(struct merged_iter));
 +	*p = merged;
 +	iterator_from_merged_iter(it, p);
 +
 +out:
 +	if (err < 0)
  		merged_iter_close(&merged);
 -		return err;
 -	} else {
 -		struct merged_iter *p =
 -			reftable_malloc(sizeof(struct merged_iter));
 -		*p = merged;
 -		iterator_from_merged_iter(it, p);
 -	}
 -	return 0;
 +	return err;
  }
  
  int reftable_merged_table_seek_ref(struct reftable_merged_table *mt,
diff --cc reftable/record.h
index e64ed30c80,0d96fbfd1b..a05e2be179
--- a/reftable/record.h
+++ b/reftable/record.h
@@@ -110,10 -119,8 +116,11 @@@ struct reftable_record 
  	} u;
  };
  
 +/* Initialize the reftable record for the given type */
 +void reftable_record_init(struct reftable_record *rec, uint8_t typ);
 +
  /* see struct record_vtable */
+ int reftable_record_cmp(struct reftable_record *a, struct reftable_record *b);
  int reftable_record_equal(struct reftable_record *a, struct reftable_record *b, int hash_size);
  void reftable_record_print(struct reftable_record *rec, int hash_size);
  void reftable_record_key(struct reftable_record *rec, struct strbuf *dest);