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Copy file name to clipboardExpand all lines: docs/en/data-modeling/schema-design.md
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-**Use strict types** - Our initial schema used Strings for many columns which are clearly numerics. Usage of the correct types will ensure the expected semantics when filtering and aggregating. The same applies to date types, which have been correctly provided in the Parquet files.
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-**Avoid Nullable Columns** - By default the above columns have been assumed to be Null. The Nullable type allows queries to determine the difference between an empty and Null value. This creates a separate column of UInt8 type. This additional column has to be processed every time a user works with a nullable column. This leads to additional storage space used and almost always negatively affects query performance. Only use Nullable if there is a difference between the default empty value for a type and Null. For example, a value of 0 for empty values in the `ViewCount` column will likely be sufficient for most queries and not impact results. If empty values should be treated differently, they can often also be excluded from queries with a filter.
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Use the minimal precision for numeric types - ClickHouse has a number of numeric types designed for different numeric ranges and precision. Always aim to minimize the number of bits used to represent a column. As well as integers of different size e.g. Int16, ClickHouse offers unsigned variants whose minimum value is 0. These can allow fewer bits to be used for a column e.g. UInt16 has a maximum value of 65535, twice that of an Int16. Prefer these types over large unsigned variants if possible.
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Use the minimal precision for numeric types - ClickHouse has a number of numeric types designed for different numeric ranges and precision. Always aim to minimize the number of bits used to represent a column. As well as integers of different size e.g. Int16, ClickHouse offers unsigned variants whose minimum value is 0. These can allow fewer bits to be used for a column e.g. UInt16 has a maximum value of 65535, twice that of an Int16. Prefer these types over larger signed variants if possible.
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-**Minimal precision for date types** - ClickHouse supports a number of date and datetime types. Date and Date32 can be used for storing pure dates, with the latter supporting a larger date range at the expense of more bits. DateTime and DateTime64 provide support for date times. DateTime is limited to second granularity and uses 32 bits. DateTime64, as the name suggests, uses 64 bits but provides support up to nanosecond granularity. As ever, choose the more coarse version acceptable for queries, minimizing the number of bits needed.
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-**Use LowCardinality** - Numbers, strings, Date or DateTime columns with a low number of unique values can potentially be encoded using the LowCardinality type. This dictionary encodes values, reducing the size on disk. Consider this for columns with less than 10k unique values.
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FixedString for special cases - Strings which have a fixed length can be encoded with the FixedString type e.g. language and currency codes. This is efficient when data has the length of precisely N bytes. In all other cases, it is likely to reduce efficiency and LowCardinality is preferred.
Copy file name to clipboardExpand all lines: docs/en/faq/general/ne-tormozit.md
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# What Does "Не тормозит" Mean? {#what-does-ne-tormozit-mean}
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This question usually arises when people see vintage (limited production) ClickHouse t-shirts. They have large words **"ClickHouse не тормозит"** on the front.
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We often get this question when people see vintage (limited production) ClickHouse t-shirts. They have the words **"ClickHouse не тормозит"** written in big bold text on the front.
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Before ClickHouse became open-source, it was developed as an in-house storage system by a large European IT company, [Yandex](https://yandex.com/company/). That’s why it initially got its slogan in Cyrillic, which is "не тормозит" (pronounced as "ne tormozit"). After the open-source release, we first produced some of those t-shirts for local events, and it was a no-brainer to use the slogan as-is.
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One of the following batches of those t-shirts was supposed to be given away at international events, and we tried to make the English version of the slogan. Unfortunately, the original phrase is kind of elegant in terms of expressing stuff, and there was a restriction of limited space on a t-shirt, so we failed to come up with a good enough translation (most options appeared to be either long or inaccurate) and decided to keep the slogan even on t-shirts produced for international events. It appeared to be a great decision because people all over the world were positively surprised and curious when they saw it.
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A second batch of these t-shirts was supposed to be given away at international events, and we tried to make an English version of the slogan.
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Unfortunately, we just couldn't come up with a punchy equivalent in English. The original phrase is elegant in its expression while being succinct, and restrictions on space on the t-shirt meant that we failed to come up with a good enough translation as most options appeared to be either too long or inaccurate.
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We decided to keep the slogan even on t-shirts produced for international events. It appeared to be a great decision because people all over the world were positively surprised and curious when they saw it.
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So, what does it mean? Here are some ways to translate *"не тормозит"*:
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- If you translate it literally, it’d be something like *"ClickHouse does not press the brake pedal"*.
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- Shorter, but not so precise versions could be *"ClickHouse is not slow"*, *"ClickHouse does not lag"* or just *"ClickHouse is fast"*.
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- If you translate it literally, it sounds something like *"ClickHouse does not press the brake pedal"*.
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- Shorter, but less precise translations might be *"ClickHouse is not slow"*, *"ClickHouse does not lag"* or just *"ClickHouse is fast"*.
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If you haven’t seen one of those t-shirts in person, you can check them out online in many ClickHouse-related videos. For example, this one:
<iframewidth="560"height="315"src="http://www.youtube.com/embed/bSyQahMVZ7w"title="YouTube video player"frameborder="0"allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share"referrerpolicy="strict-origin-when-cross-origin"allowfullscreen></iframe>
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</div>
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P.S. These t-shirts are not for sale, they were given away for free on some [ClickHouse Meetups](https://www.meetup.com/pro/clickhouse/), usually as a gift for best questions or other forms of active participation. Now, these t-shirts are no longer produced, and they have become highly-valued collector's items.
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_P.S. These t-shirts are not for sale_, they were given away for free at some [ClickHouse Meetups](https://www.meetup.com/pro/clickhouse/), usually as a gift for best questions or other forms of active participation. Now, these t-shirts are no longer produced, and they have become highlyvalued collector's items.
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