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Why do ROWSTORE tables using HASH indexes use a significant amount of memory even without any rows being added to the table?
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Tables created using hash indexes occupy memory even when they are empty. This is because, for a table using the hash index, a hash table of size 32MB is built on all the partitions of the particular database.
Hence, the total memory occupied by an empty table using the hash index would be -> 32 X the number of database partitions.
References:
Understanding Keys and Indexes in SingleStore
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