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Re: [PATCH 2/8] reftable/stack: test compaction with already-locked tables

From
Patrick Steinhardt <ps@pks.im>
Date
Aug 5, 2024, 12:11 UTC
Message-ID
<ZrDBdesFvYFP7NLU@tanuki>
In-Reply-To
<xmqqle1ebpp4.fsf@gitster.g>
On Fri, Aug 02, 2024 at 02:05:43PM -0700, Junio C Hamano wrote:
Show 18 quoted lines
> Patrick Steinhardt <ps@pks.im> writes:
> > +		ref.refname = buf.buf;
> > +
> > +		err = reftable_stack_add(st, &write_test_ref, &ref);
> > +		EXPECT_ERR(err);
> > +	}
> > +	EXPECT(st->merged->stack_len == 5);
> > +
> > +	/*
> > +	 * Given that all tables we have written should be roughly the same
> > +	 * size, we expect that auto-compaction will want to compact all of the
> > +	 * tables. Locking any of the tables will keep it from doing so.
> > +	 */
> > +	strbuf_reset(&buf);
> > +	strbuf_addf(&buf, "%s/%s.lock", dir, st->readers[2]->name);
> > +	write_file_buf(buf.buf, "", 0);
> 
> OK.  [2] is just a random number pulled out of 0..5?

Not quite as random. It is picked such that we can demonstrate in a follow-up patch that auto-compaction knows to pack tables 4 and 5, while leaking tables 1 to 3 intact. This only becomes important in a follow up patch where we change the backing logic.

Show 26 quoted lines
> > +static void test_reftable_stack_compaction_with_locked_tables(void)
> > +{
> > +	struct reftable_write_options opts = {
> > +		.disable_auto_compact = 1,
> > +	};
> > +	struct reftable_stack *st = NULL;
> > +	struct strbuf buf = STRBUF_INIT;
> > +	char *dir = get_tmp_dir(__LINE__);
> > +	int err;
> > +
> > +	err = reftable_new_stack(&st, dir, &opts);
> > +	EXPECT_ERR(err);
> > +
> > +	for (size_t i = 0; i < 3; i++) {
> > +...
> > +	}
> > +	EXPECT(st->merged->stack_len == 3);
> 
> Hmph, this somehow looks familiar.  The only difference is how many
> tables are compacted with which one locked, and whether it is
> compact_all() or auto_compact() that triggers the compaction
> behaviour, right?
> 
> I wonder if we want to factor out the commonality into a shared
> function, or it is too much trouble only for two duplicates and we
> can worry about it when we were about to add the third one?

I was also briefly thinking the same, but then didn't follow through with that thought. In fact, there's multiple places in this file where we populate a stack with N tables. I think it should be easy enough to pull this into a function indeed.

Patrick
Previous: Junio C HamanoNext: Patrick Steinhardt
Message 6 of 50 in “reftable: improvements and fixes for compaction”
  1. 0/8 reftable: improvements and fixes for compactionPatrick Steinhardt, Jul 31, 2024
  2. 1/8 reftable/stack: refactor function to gather table sizesPatrick Steinhardt, Jul 31, 2024
  3. Junio C HamanoAug 2, 2024
  4. 2/8 reftable/stack: test compaction with already-locked tablesPatrick Steinhardt, Jul 31, 2024
  5. Junio C HamanoAug 2, 2024
  6. Patrick SteinhardtAug 5, 2024
  7. 3/8 reftable/stack: update stats on failed full compactionPatrick Steinhardt, Jul 31, 2024
  8. 4/8 reftable/stack: simplify tracking of table locksPatrick Steinhardt, Jul 31, 2024
  9. Justin ToblerJul 31, 2024
  10. Junio C HamanoAug 2, 2024
  11. Patrick SteinhardtAug 5, 2024
  12. 5/8 reftable/stack: do not die when fsyncing lock file filesPatrick Steinhardt, Jul 31, 2024
  13. 6/8 reftable/stack: use lock_file when adding table to "tables.list"Patrick Steinhardt, Jul 31, 2024
  14. Justin ToblerJul 31, 2024
  15. Patrick SteinhardtAug 1, 2024
  16. 7/8 reftable/stack: fix corruption on concurrent compactionPatrick Steinhardt, Jul 31, 2024
  17. Justin ToblerAug 1, 2024
  18. Patrick SteinhardtAug 1, 2024
  19. 8/8 reftable/stack: handle locked tables during auto-compactionPatrick Steinhardt, Jul 31, 2024
  20. Junio C HamanoAug 2, 2024
  21. Patrick SteinhardtAug 5, 2024
  22. 0/9 reftable: improvements and fixes for compactionPatrick Steinhardt, Aug 5, 2024
  23. 1/9 reftable/stack: refactor function to gather table sizesPatrick Steinhardt, Aug 5, 2024
  24. 2/9 reftable/stack: extract function to setup stack with N tablesPatrick Steinhardt, Aug 5, 2024
  25. 3/9 reftable/stack: test compaction with already-locked tablesPatrick Steinhardt, Aug 5, 2024
  26. Karthik NayakAug 8, 2024
  27. 4/9 reftable/stack: update stats on failed full compactionPatrick Steinhardt, Aug 5, 2024
  28. 5/9 reftable/stack: simplify tracking of table locksPatrick Steinhardt, Aug 5, 2024
  29. 6/9 reftable/stack: do not die when fsyncing lock file filesPatrick Steinhardt, Aug 5, 2024
  30. 7/9 reftable/stack: use lock_file when adding table to "tables.list"Patrick Steinhardt, Aug 5, 2024
  31. 8/9 reftable/stack: fix corruption on concurrent compactionPatrick Steinhardt, Aug 5, 2024
  32. Karthik NayakAug 8, 2024
  33. Patrick SteinhardtAug 8, 2024
  34. 9/9 reftable/stack: handle locked tables during auto-compactionPatrick Steinhardt, Aug 5, 2024
  35. Justin ToblerAug 6, 2024
  36. Patrick SteinhardtAug 7, 2024
  37. Justin ToblerAug 7, 2024
  38. Karthik NayakAug 8, 2024
  39. Karthik NayakAug 8, 2024
  40. 0/9 reftable: improvements and fixes for compactionPatrick Steinhardt, Aug 8, 2024
  41. 1/9 reftable/stack: refactor function to gather table sizesPatrick Steinhardt, Aug 8, 2024
  42. 2/9 reftable/stack: extract function to setup stack with N tablesPatrick Steinhardt, Aug 8, 2024
  43. 3/9 reftable/stack: test compaction with already-locked tablesPatrick Steinhardt, Aug 8, 2024
  44. 4/9 reftable/stack: update stats on failed full compactionPatrick Steinhardt, Aug 8, 2024
  45. 5/9 reftable/stack: simplify tracking of table locksPatrick Steinhardt, Aug 8, 2024
  46. 6/9 reftable/stack: do not die when fsyncing lock file filesPatrick Steinhardt, Aug 8, 2024
  47. 7/9 reftable/stack: use lock_file when adding table to "tables.list"Patrick Steinhardt, Aug 8, 2024
  48. 8/9 reftable/stack: fix corruption on concurrent compactionPatrick Steinhardt, Aug 8, 2024
  49. 9/9 reftable/stack: handle locked tables during auto-compactionPatrick Steinhardt, Aug 8, 2024
  50. Karthik NayakAug 8, 2024

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