From c4720d9728ba0e264da4834dea7fcaad6b2a8322 Mon Sep 17 00:00:00 2001 From: Robert Schulze Date: Mon, 9 Sep 2024 11:18:42 +0000 Subject: [PATCH] Minor doc fixups --- .../mergetree-family/mergetree.md | 37 +++++++------------ 1 file changed, 14 insertions(+), 23 deletions(-) diff --git a/docs/en/engines/table-engines/mergetree-family/mergetree.md b/docs/en/engines/table-engines/mergetree-family/mergetree.md index d17208ab099..0bbee5f86f3 100644 --- a/docs/en/engines/table-engines/mergetree-family/mergetree.md +++ b/docs/en/engines/table-engines/mergetree-family/mergetree.md @@ -991,48 +991,39 @@ They can be used for prewhere optimization only if we enable `set allow_statisti ### Available Types of Column Statistics {#available-types-of-column-statistics} -Names of statistics types are case-insensitive, i.e. both - -``` sql -CREATE TABLE tab -( -a LowCardinality(Int64) STATISTICS(minmax) -) [...] -``` -and -``` sql -CREATE TABLE tab -( -a LowCardinality(Int64) STATISTICS(MiNmAx) -) [...] -``` -work. - - `MinMax` The minimum and maximum column value which allows to estimate the selectivity of range filters on numeric columns. + Syntax: `minmax` + - `TDigest` [TDigest](https://github.com/tdunning/t-digest) sketches which allow to compute approximate percentiles (e.g. the 90th percentile) for numeric columns. + Syntax: `tdigest` + - `Uniq` [HyperLogLog](https://en.wikipedia.org/wiki/HyperLogLog) sketches which provide an estimation how many distinct values a column contains. + Syntax: `uniq` + - `CountMin` [CountMin](https://en.wikipedia.org/wiki/Count%E2%80%93min_sketch) sketches which provide an approximate count of the frequency of each value in a column. + Syntax `countmin` + ### Supported Data Types {#supported-data-types} -| | (U)Int* | Float* | Decimal(*) | Date* | Boolean | Enum* | (Fixed)String | -|-----------|---------|--------|------------|-------|---------|-------|------------------| -| CountMin | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | -| MinMax | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✗ | -| TDigest | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✗ | -| Uniq | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | +| | (U)Int*, Float*, Decimal(*), Date*, Boolean, Enum* | String or FixedString | +|-----------|----------------------------------------------------|-----------------------| +| CountMin | ✔ | ✔ | +| MinMax | ✔ | ✗ | +| TDigest | ✔ | ✗ | +| Uniq | ✔ | ✔ | ### Supported Operations {#supported-operations}