Subject: [PATCH v2 00/11] reftable: expose write options as config

From: Patrick Steinhardt <[email-masked]>
Date: Fri, 10 May 2024 12:29:16 +0200

Hi,

this is the second version of my patch series that exposes various
options of the reftable writer via Git configuration.

Changes compared to v1:

  - Drop unneeded return statements.

  - Move default geometric factor into "constants.h".

  - Fix a typo in a commit message.

Thanks!

Patrick

Patrick Steinhardt (11):
  reftable: consistently refer to `reftable_write_options` as `opts`
  reftable: consistently pass write opts as value
  reftable/writer: drop static variable used to initialize strbuf
  reftable/writer: improve error when passed an invalid block size
  reftable/dump: support dumping a table's block structure
  refs/reftable: allow configuring block size
  reftable: use `uint16_t` to track restart interval
  refs/reftable: allow configuring restart interval
  refs/reftable: allow disabling writing the object index
  reftable: make the compaction factor configurable
  refs/reftable: allow configuring geometric factor

 Documentation/config.txt          |   2 +
 Documentation/config/reftable.txt |  49 +++++
 refs/reftable-backend.c           |  43 ++++-
 reftable/block.h                  |   2 +-
 reftable/constants.h              |   1 +
 reftable/dump.c                   |  12 +-
 reftable/merged_test.c            |   6 +-
 reftable/reader.c                 |  63 +++++++
 reftable/readwrite_test.c         |  26 +--
 reftable/refname_test.c           |   2 +-
 reftable/reftable-reader.h        |   2 +
 reftable/reftable-stack.h         |   2 +-
 reftable/reftable-writer.h        |  10 +-
 reftable/stack.c                  |  57 +++---
 reftable/stack.h                  |   5 +-
 reftable/stack_test.c             | 118 ++++++------
 reftable/writer.c                 |  20 +--
 t/t0613-reftable-write-options.sh | 286 ++++++++++++++++++++++++++++++
 18 files changed, 576 insertions(+), 130 deletions(-)
 create mode 100644 Documentation/config/reftable.txt
 create mode 100755 t/t0613-reftable-write-options.sh

Range-diff against v1:
 1:  47cee6e25e =  1:  7efa566306 reftable: consistently refer to `reftable_write_options` as `opts`
 2:  d8a0764e87 =  2:  e6f8fc09c2 reftable: consistently pass write opts as value
 3:  c040f81fba =  3:  aa2903e3e5 reftable/writer: drop static variable used to initialize strbuf
 4:  ef79bb1b7b =  4:  5e7cbb7b19 reftable/writer: improve error when passed an invalid block size
 5:  4d4407d4a4 =  5:  ed1c150d90 reftable/dump: support dumping a table's block structure
 6:  b4e4db5735 !  6:  be5bdc6dc1 refs/reftable: allow configuring block size
    @@ refs/reftable-backend.c: static int read_ref_without_reload(struct reftable_stac
     +		if (block_size > 16777215)
     +			die("reftable block size cannot exceed 16MB");
     +		opts->block_size = block_size;
    -+		return 0;
     +	}
     +
     +	return 0;
 7:  79d9e07ca9 =  7:  05e8d1df2d reftable: use `uint16_t` to track restart interval
 8:  653ec4dfa5 !  8:  bc0bf65553 refs/reftable: allow configuring restart interval
    @@ Documentation/config/reftable.txt: readers during access.
     
      ## refs/reftable-backend.c ##
     @@ refs/reftable-backend.c: static int reftable_be_config(const char *var, const char *value,
    + 		if (block_size > 16777215)
      			die("reftable block size cannot exceed 16MB");
      		opts->block_size = block_size;
    - 		return 0;
     +	} else if (!strcmp(var, "reftable.restartinterval")) {
     +		unsigned long restart_interval = git_config_ulong(var, value, ctx->kvi);
     +		if (restart_interval > UINT16_MAX)
     +			die("reftable block size cannot exceed %u", (unsigned)UINT16_MAX);
     +		opts->restart_interval = restart_interval;
    -+		return 0;
      	}
      
      	return 0;
 9:  6f2c481acc !  9:  6bc240fd0c refs/reftable: allow disabling writing the object index
    @@ Documentation/config/reftable.txt: A maximum of `65535` restart points per block
     
      ## refs/reftable-backend.c ##
     @@ refs/reftable-backend.c: static int reftable_be_config(const char *var, const char *value,
    + 		if (restart_interval > UINT16_MAX)
      			die("reftable block size cannot exceed %u", (unsigned)UINT16_MAX);
      		opts->restart_interval = restart_interval;
    - 		return 0;
     +	} else if (!strcmp(var, "reftable.indexobjects")) {
     +		opts->skip_index_objects = !git_config_bool(var, value);
    -+		return 0;
      	}
      
      	return 0;
10:  30e2e33479 ! 10:  9d4c1f0340 reftable: make the compaction factor configurable
    @@ Commit message
     
         Signed-off-by: Patrick Steinhardt <[email-masked]>
     
    + ## reftable/constants.h ##
    +@@ reftable/constants.h: license that can be found in the LICENSE file or at
    + 
    + #define MAX_RESTARTS ((1 << 16) - 1)
    + #define DEFAULT_BLOCK_SIZE 4096
    ++#define DEFAULT_GEOMETRIC_FACTOR 2
    + 
    + #endif
    +
      ## reftable/reftable-writer.h ##
     @@ reftable/reftable-writer.h: struct reftable_write_options {
      
    @@ reftable/reftable-writer.h: struct reftable_write_options {
      /* reftable_block_stats holds statistics for a single block type */
     
      ## reftable/stack.c ##
    +@@ reftable/stack.c: license that can be found in the LICENSE file or at
    + 
    + #include "../write-or-die.h"
    + #include "system.h"
    ++#include "constants.h"
    + #include "merged.h"
    + #include "reader.h"
    + #include "refname.h"
     @@ reftable/stack.c: static int segment_size(struct segment *s)
      	return s->end - s->start;
      }
    @@ reftable/stack.c: static int segment_size(struct segment *s)
      	size_t i;
      
     +	if (!factor)
    -+		factor = 2;
    ++		factor = DEFAULT_GEOMETRIC_FACTOR;
     +
      	/*
      	 * If there are no tables or only a single one then we don't have to
11:  861f2e72d9 ! 11:  e1282e53fb refs/reftable: allow configuring geometric factor
    @@ Documentation/config/reftable.txt: reftable.indexObjects::
      The default value is `true`.
     +
     +reftable.geometricFactor::
    -+	Whenever the reftable backend appends a new table to the table it
    ++	Whenever the reftable backend appends a new table to the stack, it
     +	performs auto compaction to ensure that there is only a handful of
     +	tables. The backend does this by ensuring that tables form a geometric
     +	sequence regarding the respective sizes of each table.
    @@ Documentation/config/reftable.txt: reftable.indexObjects::
     
      ## refs/reftable-backend.c ##
     @@ refs/reftable-backend.c: static int reftable_be_config(const char *var, const char *value,
    + 		opts->restart_interval = restart_interval;
      	} else if (!strcmp(var, "reftable.indexobjects")) {
      		opts->skip_index_objects = !git_config_bool(var, value);
    - 		return 0;
     +	} else if (!strcmp(var, "reftable.geometricfactor")) {
     +		unsigned long factor = git_config_ulong(var, value, ctx->kvi);
     +		if (factor > UINT8_MAX)

base-commit: d4cc1ec35f3bcce816b69986ca41943f6ce21377
-- 
2.45.0