[tarantool-patches] [PATCH] Add MsgPack ext types handling.
Konstantin Osipov
kostja at tarantool.org
Tue Apr 23 15:21:46 MSK 2019
* Serge Petrenko <sergepetrenko at tarantool.org> [19/04/23 15:09]:
I mentioned before that this would break all clients.
It's high time to reconsider our in-memory storage format and make
it different from serialization format: we're seeing significant
performance penalty with serialization to and from msgpack in SQL,
and DECIMAL is a yet another blow on the single-format-approach:
our clients are simply not prepared to handle non-standard
extensions.
Let's investigate what it takes to store decimal as an mp ext, and
serialize as mp string.
> Add the ability to encode/decode MsgPack ext types,
> introduce the first extension type: MP_EXT_DECIMAL: it will be used to
> store decimals in tarantool.
>
> Needed-for tarantool/tarantool#692
> ---
> https://github.com/tarantool/msgpuck/tree/sp/add-extension-types
> https://github.com/tarantool/tarantool/issues/692
>
> hints.c | 24 +++++++++
> msgpuck.c | 20 +++++++-
> msgpuck.h | 133 +++++++++++++++++++++++++++++++++++++++++++++++++
> test/msgpuck.c | 7 ++-
> 4 files changed, 178 insertions(+), 6 deletions(-)
>
> diff --git a/hints.c b/hints.c
> index be859e9..0ab4f4d 100644
> --- a/hints.c
> +++ b/hints.c
> @@ -672,3 +672,27 @@ const char *mp_char2escape[128] = {
> NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
> NULL, NULL, NULL, NULL, NULL, NULL, NULL, "\\u007f"
> };
> +
> +/*
> + * This lookup table is used by mp_encode_ext() to
> + * determine ext code (fixext 1, fixext 2, fixext 4, fixext 8,
> + * fixext 16) to encode using size.
> + */
> +const uint8_t mp_ext_hint[16] = {
> + 0xd4, /* 1 */
> + 0xd5, /* 2 */
> + 0xd6, /* 3 */
> + 0xd6, /* 4 */
> + 0xd7, /* 5 */
> + 0xd7, /* 6 */
> + 0xd7, /* 7 */
> + 0xd7, /* 8 */
> + 0xd8, /* 9 */
> + 0xd8, /* 10 */
> + 0xd8, /* 11 */
> + 0xd8, /* 12 */
> + 0xd8, /* 13 */
> + 0xd8, /* 14 */
> + 0xd8, /* 15 */
> + 0xd8 /* 16 */
> +};
> diff --git a/msgpuck.c b/msgpuck.c
> index d0ffb83..04aeb0f 100644
> --- a/msgpuck.c
> +++ b/msgpuck.c
> @@ -33,6 +33,17 @@
> #define MP_LIBRARY 1
> #include "msgpuck.h"
>
> +const char *
> +mp_ext_type_str(enum mp_ext_type type)
> +{
> + switch(type) {
> + case MP_EXT_DECIMAL:
> + return "decimal";
> + default:
> + return "undefined";
> + }
> +}
> +
> size_t
> mp_vformat(char *data, size_t data_size, const char *format, va_list vl)
> {
> @@ -298,9 +309,14 @@ next: \
> PRINTF("%lg", mp_decode_double(&data)); \
> break; \
> case MP_EXT: \
> - mp_next(&data); \
> - PRINTF("undefined"); \
> + { \
> + uint8_t type; \
> + uint32_t len; \
> + len = mp_decode_ext(&data, &len, &type); \
> + PRINTF("%s", mp_ext_type_str(type)); \
> + data += len; \
> break; \
> + } \
> default: \
> mp_unreachable(); \
> return -1; \
> diff --git a/msgpuck.h b/msgpuck.h
> index 6b29cd6..0a7d230 100644
> --- a/msgpuck.h
> +++ b/msgpuck.h
> @@ -382,6 +382,13 @@ enum mp_type {
> MP_EXT
> };
>
> +/**
> + * \brief MsgPack extension data types.
> + */
> +enum mp_ext_type {
> + MP_EXT_DECIMAL = 0
> +};
> +
> /**
> * \brief Determine MsgPack type by a first byte \a c of encoded data.
> *
> @@ -532,6 +539,49 @@ mp_check_map(const char *cur, const char *end);
> MP_PROTO uint32_t
> mp_decode_map(const char **data);
>
> +/**
> + * \brief calculate exact buffer size needed to store
> + * ext value of length \a len.
> + * \param len value length in bytes.
> + * \retval buffer size in bytes
> + */
> +MP_PROTO uint32_t
> +mp_sizeof_ext(uint32_t len);
> +
> +/**
> + * \brief Encode extension header with \a type and
> + * value length \a len.
> + * The value must be encoded after the header.
> + * \return \a data + \link mp_sizeof_ext() mp_sizeof_ext(size)\endlink
> + */
> +MP_PROTO char *
> +mp_encode_ext(char *data, uint8_t type, uint32_t len);
> +
> +/**
> + * \brief Check that \a cur buffer has enough bytes to decode a map header.
> + * \param cur buffer
> + * \param end end of the buffer
> + * \retval 0 - buffer has enough bytes
> + * \retval > 0 - the numbeer of remaining bytes to read
> + * \pre cur < end
> + * \pre mp_typeof(*cur) == MP_EXT
> + */
> +MP_PROTO MP_PURE ptrdiff_t
> +mp_check_ext(const char *cur, const char *end);
> +
> +/**
> + * \brief Decode an extension header from MsgPack \a data.
> + *
> + * The extension type value must be decoded after the header.
> + * \param data - the pointer to a buffer.
> + * \param len - decoded length of the following value.
> + * \param type - decoded type of the following value.
> + * \retval - the length of the following ext value.
> + * \post *data = *data + mp_sizeof_ext(length)
> + */
> +MP_PROTO uint32_t
> +mp_decode_ext(const char **data, uint32_t *len, uint8_t *type);
> +
> /**
> * \brief Calculate exact buffer size needed to store an integer \a num.
> * Maximum return value is 9. For performance reasons you can preallocate
> @@ -1326,6 +1376,7 @@ mp_frame_advance(struct mp_frame *frame);
> extern const enum mp_type mp_type_hint[];
> extern const int8_t mp_parser_hint[];
> extern const char *mp_char2escape[];
> +extern const uint8_t mp_ext_hint[];
>
> MP_IMPL MP_ALWAYSINLINE enum mp_type
> mp_typeof(const char c)
> @@ -1462,6 +1513,88 @@ mp_decode_map(const char **data)
> }
> }
>
> +MP_IMPL uint32_t
> +mp_sizeof_ext(uint32_t len)
> +{
> + if (len <= 16) return 2;
> + if (len <= UINT8_MAX) return 3;
> + if (len <= UINT16_MAX) return 4;
> + else return 5;
> +}
> +
> +MP_IMPL char *
> +mp_encode_ext(char *data, uint8_t type, uint32_t len)
> +{
> + /*
> + * zero-length should be encoded in EXT 8, because
> + * fixext always assumes exact length (1, 2, 4, 8 and 16).
> + */
> + if (len <= 16 && len > 0) {
> + data = mp_store_u8(data, mp_ext_hint[len-1]);
> + } else if (len <= UINT8_MAX) {
> + data = mp_store_u8(data, 0xc7);
> + data = mp_store_u8(data, (uint8_t) len);
> + } else if (len <= UINT16_MAX) {
> + data = mp_store_u8(data, 0xc8);
> + data = mp_store_u16(data, (uint16_t) len);
> + } else {
> + data = mp_store_u8(data, 0xc9);
> + data = mp_store_u32(data, (uint32_t) len);
> + }
> + data = mp_store_u8(data, type);
> + return data;
> +}
> +
> +MP_IMPL ptrdiff_t
> +mp_check_ext(const char *cur, const char *end)
> +{
> + assert(cur < end);
> + assert(mp_typeof(*cur) == MP_EXT);
> + uint8_t c = mp_load_u8(&cur);
> + switch (c) {
> + case 0xd4:
> + case 0xd5:
> + case 0xd6:
> + case 0xd7:
> + case 0xd8:
> + return 1 - (end - cur);
> + case 0xc7:
> + case 0xc8:
> + return c - 0xc4 - (end - cur);
> + case 0xc9:
> + return 6 - (end - cur);
> + default:
> + mp_unreachable();
> + }
> +}
> +
> +MP_IMPL uint32_t
> +mp_decode_ext(const char **data, uint32_t *len, uint8_t *type) {
> + uint8_t c = mp_load_u8(data);
> + switch (c) {
> + case 0xd4:
> + case 0xd5:
> + case 0xd6:
> + case 0xd7:
> + case 0xd8:
> + *len = 1u << (c - 0xd4);
> + break;
> + case 0xc7:
> + *len = mp_load_u8(data);
> + break;
> + case 0xc8:
> + *len = mp_load_u16(data);
> + break;
> + case 0xc9:
> + *len = mp_load_u32(data);
> + break;
> + default:
> + mp_unreachable();
> + }
> + *type = mp_load_u8(data);
> + return *len;
> +}
> +
> MP_IMPL uint32_t
> mp_sizeof_uint(uint64_t num)
> {
> diff --git a/test/msgpuck.c b/test/msgpuck.c
> index 3b31bfc..5ddaba7 100644
> --- a/test/msgpuck.c
> +++ b/test/msgpuck.c
> @@ -789,9 +789,8 @@ test_mp_print()
> d = mp_encode_double(d, 3.14);
> d = mp_encode_uint(d, 100);
> d = mp_encode_uint(d, 500);
> - *d++ = 0xd4; /* let's pack smallest fixed ext */
> - *d++ = 0;
> - *d++ = 0;
> + /* let's pack zero-length ext */
> + d = mp_encode_ext(d, MP_EXT_DECIMAL, 0);
> char bin[] = "\x12test\x34\b\t\n\"bla\\-bla\"\f\r";
> d = mp_encode_bin(d, bin, sizeof(bin));
> d = mp_encode_map(d, 0);
> @@ -800,7 +799,7 @@ test_mp_print()
> const char *expected =
> "[-5, 42, \"kill bill\", [], "
> "{\"bool true\": true, \"bool false\": false, \"null\": null, "
> - "\"float\": 3.14, \"double\": 3.14, 100: 500}, undefined, "
> + "\"float\": 3.14, \"double\": 3.14, 100: 500}, decimal, "
> "\"\\u0012test4\\b\\t\\n\\\"bla\\\\-bla\\\"\\f\\r\\u0000\", {}]";
> int esize = strlen(expected);
>
> --
> 2.20.1 (Apple Git-117)
>
--
Konstantin Osipov, Moscow, Russia, +7 903 626 22 32
http://tarantool.io - www.twitter.com/kostja_osipov
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