containers Table Column Constraints-opracowanie

containers Table Column Constraints
• key_columns: The maximum limit for a memcached key is 250 characters, which is enforced by
memcached. If a mapped key longer than the maximum limit is used, the operation will fail. The
mapped key must be a non-Null CHAR or VARCHAR type.
• value_columns: Must be mapped to a CHAR, VARCHAR, or BLOB column. There is no length
restriction and the value can be NULL.
• cas_column: The cas value is a 64 bit integer. It must be mapped to a BIGINT of at least 8 bytes
and can be NULL.
• expiration_time_column: Must mapped to an INTEGER of at least 4 bytes and can be NULL.
Expiration time is defined as a 32-bit integer for Unix time (the number of seconds since January 1,
1970, as a 32-bit value), or the number of seconds starting from the current time. For the latter, the
number of seconds may not exceed 60*60*24*30 (the number of seconds in 30 days). If the number
sent by a client is larger, the server will consider it to be a real Unix time value rather than an offset
from the current time.
• flags: Must be mapped to an INTEGER of at least 32-bits and can be NULL.
A pre-check is performed at plugin load time to enforce column constraints. If any mismatches are
found, the plugin will not load.
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