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Point to existing system tables for alternatives
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Robert Schulze
parent
82e38f7736
commit
966e93b908
@ -286,21 +286,21 @@ equivalent. If no database is specified, the query assumes the current database
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The optional keyword `EXTENDED` currently has no effect, it only exists for MySQL compatibility.
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The statement produces a result table with the following structure:
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- table - The name of the table (String)
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- table - The name of the table. (String)
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- non_unique - Always `1` as ClickHouse does not support uniqueness constraints. (UInt8)
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- key_name - The name of the index, `PRIMARY` if the index is a primary key index (String)
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- seq_in_index - Currently unused
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- column_name - Currently unused
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- collation - The sorting of the column in the index, `A` if ascending, `D` if descending, `NULL` if unsorted (Nullable(String))
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- key_name - The name of the index, `PRIMARY` if the index is a primary key index. (String)
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- seq_in_index - Currently always `1`. (In MySQL, this field denotes the position of the column in a non-functional index.) (UInt8)
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- column_name - Currently always `` (empty string), also see field `expression`. (In MySQL, this field denotes the name of the column in a non-functional index.) (String)
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- collation - The sorting of the column in the index: `A` if ascending, `D` if descending, `NULL` if unsorted. (Nullable(String))
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- cardinality - An estimation of the index cardinality (number of unique values in the index). Currently always 0. (UInt64)
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- sub_part - Always `NULL` because ClickHouse does not support index prefixes like MySQL (Nullable(String))
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- packed - Always `NULL` because ClickHouse does not support packed (prefix-compressed) indexes like MySQL (Nullable(String))
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- sub_part - Always `NULL` because ClickHouse does not support index prefixes like MySQL. (Nullable(String))
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- packed - Always `NULL` because ClickHouse does not support packed indexes (like MySQL). (Nullable(String))
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- null - Currently unused
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- index_type - The index type, e.g. `PRIMARY`, `MINMAX`, `BLOOM_FILTER` etc. (String)
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- comment - Additional information about the index, currently always `` (empty string) (String)
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- index_comment - `` (empty string) because indexes in ClickHouse cannot have a `COMMENT` field like in MySQL (String)
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- visible - If the index is visible to the optimizer, always `YES` (String)
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- expression - The index expression (String)
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- comment - Additional information about the index, currently always `` (empty string). (String)
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- index_comment - `` (empty string) because indexes in ClickHouse cannot have a `COMMENT` field (like in MySQL). (String)
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- visible - If the index is visible to the optimizer, always `YES`. (String)
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- expression - The index expression. (In MySQL this field is only used for functional-indexes.) (String)
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**Examples**
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@ -314,11 +314,11 @@ Result:
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``` text
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┌─table─┬─non_unique─┬─key_name─┬─seq_in_index─┬─column_name─┬─collation─┬─cardinality─┬─sub_part─┬─packed─┬─null─┬─index_type───┬─comment─┬─index_comment─┬─visible─┬─expression─┐
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│ tbl │ 1 │ blf_idx │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ 0 │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ BLOOM_FILTER │ │ │ YES │ d, b │
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│ tbl │ 1 │ mm1_idx │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ 0 │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ MINMAX │ │ │ YES │ a, c, d │
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│ tbl │ 1 │ mm2_idx │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ 0 │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ MINMAX │ │ │ YES │ c, d, e │
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│ tbl │ 1 │ PRIMARY │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ A │ 0 │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ PRIMARY │ │ │ YES │ c, a │
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│ tbl │ 1 │ set_idx │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ 0 │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ SET │ │ │ YES │ e │
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│ tbl │ 1 │ blf_idx │ 1 │ │ ᴺᵁᴸᴸ │ 0 │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ BLOOM_FILTER │ │ │ YES │ d, b │
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│ tbl │ 1 │ mm1_idx │ 1 │ │ ᴺᵁᴸᴸ │ 0 │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ MINMAX │ │ │ YES │ a, c, d │
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│ tbl │ 1 │ mm2_idx │ 1 │ │ ᴺᵁᴸᴸ │ 0 │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ MINMAX │ │ │ YES │ c, d, e │
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│ tbl │ 1 │ PRIMARY │ 1 │ │ A │ 0 │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ PRIMARY │ │ │ YES │ c, a │
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│ tbl │ 1 │ set_idx │ 1 │ │ ᴺᵁᴸᴸ │ 0 │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ SET │ │ │ YES │ e │
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└───────┴────────────┴──────────┴──────────────┴─────────────┴───────────┴─────────────┴──────────┴────────┴──────┴──────────────┴─────────┴───────────────┴─────────┴────────────┘
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```
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@ -42,8 +42,8 @@ FROM (
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name AS table,
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1 AS non_unique,
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'PRIMARY' AS key_name,
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NULL AS seq_in_index,
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NULL AS column_name,
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1 AS seq_in_index,
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'' AS column_name,
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'A' AS collation,
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0 AS cardinality,
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NULL AS sub_part,
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@ -63,8 +63,8 @@ FROM (
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table AS table,
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1 AS non_unique,
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name AS key_name,
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NULL AS seq_in_index,
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NULL AS column_name,
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1 AS seq_in_index,
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'' AS column_name,
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NULL AS collation,
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0 AS cardinality,
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NULL AS sub_part,
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@ -1,45 +1,45 @@
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--- Aliases of SHOW INDEX
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tbl 1 blf_idx \N \N \N 0 \N \N \N BLOOM_FILTER YES d, b
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tbl 1 mm1_idx \N \N \N 0 \N \N \N MINMAX YES a, c, d
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tbl 1 mm2_idx \N \N \N 0 \N \N \N MINMAX YES c, d, e
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tbl 1 PRIMARY \N \N A 0 \N \N \N PRIMARY YES c, a
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tbl 1 set_idx \N \N \N 0 \N \N \N SET YES e
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tbl 1 blf_idx \N \N \N 0 \N \N \N BLOOM_FILTER YES d, b
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tbl 1 mm1_idx \N \N \N 0 \N \N \N MINMAX YES a, c, d
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tbl 1 mm2_idx \N \N \N 0 \N \N \N MINMAX YES c, d, e
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tbl 1 PRIMARY \N \N A 0 \N \N \N PRIMARY YES c, a
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tbl 1 set_idx \N \N \N 0 \N \N \N SET YES e
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tbl 1 blf_idx \N \N \N 0 \N \N \N BLOOM_FILTER YES d, b
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tbl 1 mm1_idx \N \N \N 0 \N \N \N MINMAX YES a, c, d
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tbl 1 mm2_idx \N \N \N 0 \N \N \N MINMAX YES c, d, e
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tbl 1 PRIMARY \N \N A 0 \N \N \N PRIMARY YES c, a
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tbl 1 set_idx \N \N \N 0 \N \N \N SET YES e
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tbl 1 blf_idx \N \N \N 0 \N \N \N BLOOM_FILTER YES d, b
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tbl 1 mm1_idx \N \N \N 0 \N \N \N MINMAX YES a, c, d
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tbl 1 mm2_idx \N \N \N 0 \N \N \N MINMAX YES c, d, e
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tbl 1 PRIMARY \N \N A 0 \N \N \N PRIMARY YES c, a
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tbl 1 set_idx \N \N \N 0 \N \N \N SET YES e
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tbl 1 blf_idx 1 \N 0 \N \N \N BLOOM_FILTER YES d, b
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tbl 1 mm1_idx 1 \N 0 \N \N \N MINMAX YES a, c, d
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tbl 1 mm2_idx 1 \N 0 \N \N \N MINMAX YES c, d, e
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tbl 1 PRIMARY 1 A 0 \N \N \N PRIMARY YES c, a
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tbl 1 set_idx 1 \N 0 \N \N \N SET YES e
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tbl 1 blf_idx 1 \N 0 \N \N \N BLOOM_FILTER YES d, b
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tbl 1 mm1_idx 1 \N 0 \N \N \N MINMAX YES a, c, d
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tbl 1 mm2_idx 1 \N 0 \N \N \N MINMAX YES c, d, e
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tbl 1 PRIMARY 1 A 0 \N \N \N PRIMARY YES c, a
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tbl 1 set_idx 1 \N 0 \N \N \N SET YES e
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tbl 1 blf_idx 1 \N 0 \N \N \N BLOOM_FILTER YES d, b
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tbl 1 mm1_idx 1 \N 0 \N \N \N MINMAX YES a, c, d
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tbl 1 mm2_idx 1 \N 0 \N \N \N MINMAX YES c, d, e
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tbl 1 PRIMARY 1 A 0 \N \N \N PRIMARY YES c, a
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tbl 1 set_idx 1 \N 0 \N \N \N SET YES e
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tbl 1 blf_idx 1 \N 0 \N \N \N BLOOM_FILTER YES d, b
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tbl 1 mm1_idx 1 \N 0 \N \N \N MINMAX YES a, c, d
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tbl 1 mm2_idx 1 \N 0 \N \N \N MINMAX YES c, d, e
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tbl 1 PRIMARY 1 A 0 \N \N \N PRIMARY YES c, a
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tbl 1 set_idx 1 \N 0 \N \N \N SET YES e
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--- EXTENDED
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tbl 1 blf_idx \N \N \N 0 \N \N \N BLOOM_FILTER YES d, b
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tbl 1 mm1_idx \N \N \N 0 \N \N \N MINMAX YES a, c, d
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tbl 1 mm2_idx \N \N \N 0 \N \N \N MINMAX YES c, d, e
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tbl 1 PRIMARY \N \N A 0 \N \N \N PRIMARY YES c, a
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tbl 1 set_idx \N \N \N 0 \N \N \N SET YES e
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tbl 1 blf_idx 1 \N 0 \N \N \N BLOOM_FILTER YES d, b
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tbl 1 mm1_idx 1 \N 0 \N \N \N MINMAX YES a, c, d
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tbl 1 mm2_idx 1 \N 0 \N \N \N MINMAX YES c, d, e
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tbl 1 PRIMARY 1 A 0 \N \N \N PRIMARY YES c, a
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tbl 1 set_idx 1 \N 0 \N \N \N SET YES e
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--- WHERE
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--- Check with weird table names
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$4@^7 1 PRIMARY \N \N A 0 \N \N \N PRIMARY YES c
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NULL 1 PRIMARY \N \N A 0 \N \N \N PRIMARY YES c
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\' 1 PRIMARY \N \N A 0 \N \N \N PRIMARY YES c
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\' 1 PRIMARY \N \N A 0 \N \N \N PRIMARY YES c
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$4@^7 1 PRIMARY 1 A 0 \N \N \N PRIMARY YES c
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NULL 1 PRIMARY 1 A 0 \N \N \N PRIMARY YES c
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\' 1 PRIMARY 1 A 0 \N \N \N PRIMARY YES c
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\' 1 PRIMARY 1 A 0 \N \N \N PRIMARY YES c
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--- Original table
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tbl 1 blf_idx \N \N \N 0 \N \N \N BLOOM_FILTER YES d, b
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tbl 1 mm1_idx \N \N \N 0 \N \N \N MINMAX YES a, c, d
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tbl 1 mm2_idx \N \N \N 0 \N \N \N MINMAX YES c, d, e
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tbl 1 PRIMARY \N \N A 0 \N \N \N PRIMARY YES c, a
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tbl 1 set_idx \N \N \N 0 \N \N \N SET YES e
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tbl 1 blf_idx 1 \N 0 \N \N \N BLOOM_FILTER YES d, b
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tbl 1 mm1_idx 1 \N 0 \N \N \N MINMAX YES a, c, d
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tbl 1 mm2_idx 1 \N 0 \N \N \N MINMAX YES c, d, e
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tbl 1 PRIMARY 1 A 0 \N \N \N PRIMARY YES c, a
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tbl 1 set_idx 1 \N 0 \N \N \N SET YES e
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--- Equally named table in other database
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tbl 1 mmi_idx \N \N \N 0 \N \N \N MINMAX YES b
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tbl 1 PRIMARY \N \N A 0 \N \N \N PRIMARY YES a
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tbl 1 mmi_idx 1 \N 0 \N \N \N MINMAX YES b
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tbl 1 PRIMARY 1 A 0 \N \N \N PRIMARY YES a
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--- Short form
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tbl 1 mmi_idx \N \N \N 0 \N \N \N MINMAX YES b
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tbl 1 PRIMARY \N \N A 0 \N \N \N PRIMARY YES a
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tbl 1 mmi_idx 1 \N 0 \N \N \N MINMAX YES b
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tbl 1 PRIMARY 1 A 0 \N \N \N PRIMARY YES a
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