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Cosmetics, pt. V

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Robert Schulze 2024-04-30 10:57:36 +00:00
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2
docs/en/sql-reference/functions/uuid-functions.md
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@ -203,7 +203,7 @@ SELECT generateUUIDv7ThreadMonotonic(1), generateUUIDv7ThreadMonotonic(2);
Generates a [UUID](../data-types/uuid.md) of [version 7](https://datatracker.ietf.org/doc/html/draft-peabody-dispatch-new-uuid-format-04).
The generated UUID contains the current Unix timestamp in milliseconds (48 bits), followed by version "7" (4 bits) and random values (76 bits, including a 2-bit variant field "2").
The generated UUID contains the current Unix timestamp in milliseconds (48 bits), followed by version "7" (4 bits) and a random field (76 bits, including a 2-bit variant field "2").
This function is the fastest `generateUUIDv7*` function but it gives no monotonicity guarantees within a timestamp.

6
src/Functions/generateUUIDv7.cpp
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@ -76,7 +76,7 @@ void setVariant(UUID & uuid)
struct FillAllRandomPolicy
{
static constexpr auto name = "generateUUIDv7NonMonotonic";
static constexpr auto doc_description = R"(Generates a UUID of version 7. The generated UUID contains the current Unix timestamp in milliseconds (48 bits), followed by version "7" (4 bits), and a random field (74 bit) to distinguish UUIDs within a millisecond (including a variant field "2", 2 bit). This function is the fastest generateUUIDv7* function but it gives no monotonicity guarantees within a timestamp.)";
static constexpr auto doc_description = R"(Generates a UUID of version 7. The generated UUID contains the current Unix timestamp in milliseconds (48 bits), followed by version "7" (4 bits), and a random field (74 bit, including a 2-bit variant field "2") to distinguish UUIDs within a millisecond. This function is the fastest generateUUIDv7* function but it gives no monotonicity guarantees within a timestamp.)";
struct Data
{
void generate(UUID & uuid, uint64_t ts)
@ -136,7 +136,7 @@ struct CounterFields
struct GlobalCounterPolicy
{
static constexpr auto name = "generateUUIDv7";
static constexpr auto doc_description = R"(Generates a UUID of version 7. The generated UUID contains the current Unix timestamp in milliseconds (48 bits), followed by version "7" (4 bits), a counter (42 bit) to distinguish UUIDs within a millisecond (including a variant field "2", 2 bit), and a random field (32 bits). For any given timestamp (unix_ts_ms), the counter starts at a random value and is incremented by 1 for each new UUID until the timestamp changes. In case the counter overflows, the timestamp field is incremented by 1 and the counter is reset to a random new start value. Function generateUUIDv7 guarantees that the counter field within a timestamp increments monotonically across all function invocations in concurrently running threads and queries.)";
static constexpr auto doc_description = R"(Generates a UUID of version 7. The generated UUID contains the current Unix timestamp in milliseconds (48 bits), followed by version "7" (4 bits), a counter (42 bit, including a variant field "2", 2 bit) to distinguish UUIDs within a millisecond, and a random field (32 bits). For any given timestamp (unix_ts_ms), the counter starts at a random value and is incremented by 1 for each new UUID until the timestamp changes. In case the counter overflows, the timestamp field is incremented by 1 and the counter is reset to a random new start value. Function generateUUIDv7 guarantees that the counter field within a timestamp increments monotonically across all function invocations in concurrently running threads and queries.)";
/// Guarantee counter monotonicity within one timestamp across all threads generating UUIDv7 simultaneously.
struct Data
@ -159,7 +159,7 @@ struct GlobalCounterPolicy
struct ThreadLocalCounterPolicy
{
static constexpr auto name = "generateUUIDv7ThreadMonotonic";
static constexpr auto doc_description = R"(Generates a UUID of version 7. The generated UUID contains the current Unix timestamp in milliseconds (48 bits), followed by version "7" (4 bits), a counter (42 bit) to distinguish UUIDs within a millisecond (including a variant field "2", 2 bit), and a random field (32 bits). For any given timestamp (unix_ts_ms), the counter starts at a random value and is incremented by 1 for each new UUID until the timestamp changes. In case the counter overflows, the timestamp field is incremented by 1 and the counter is reset to a random new start value. This function behaves like generateUUIDv7 but gives no guarantee on counter monotony across different simultaneous requests. Monotonicity within one timestamp is guaranteed only within the same thread calling this function to generate UUIDs.)";
static constexpr auto doc_description = R"(Generates a UUID of version 7. The generated UUID contains the current Unix timestamp in milliseconds (48 bits), followed by version "7" (4 bits), a counter (42 bit, including a variant field "2", 2 bit) to distinguish UUIDs within a millisecond, and a random field (32 bits). For any given timestamp (unix_ts_ms), the counter starts at a random value and is incremented by 1 for each new UUID until the timestamp changes. In case the counter overflows, the timestamp field is incremented by 1 and the counter is reset to a random new start value. This function behaves like generateUUIDv7 but gives no guarantee on counter monotony across different simultaneous requests. Monotonicity within one timestamp is guaranteed only within the same thread calling this function to generate UUIDs.)";
/// Guarantee counter monotonicity within one timestamp within the same thread. Faster than GlobalCounterPolicy if a query uses multiple threads.
struct Data