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Does MySQL support TTL?
Because TiDB is MySQL compatible, TiDB’s TTL table can automatically delete the expired data according to the retention cycle set by the user.
What is database TTL?
Time to Live (TTL) is a mechanism that allows you to automatically expire database records. TTL is expressed as the amount of time data is allowed to live in the database. Data which has reached its expiration timeout value can no longer be retrieved, and will not appear in any database statistics.
What is a record in MySQL?
1) In computer data processing, a record is a collection of data items arranged for processing by a program. Multiple records are contained in a file or data set. Typically, records can be of fixed-length or be of variable length with the length information contained within the record.
What means TTL?
Time-to-live
Time-to-live (TTL) is a value for the period of time that a packet, or data, should exist on a computer or network before being discarded.
Can you create a TTL Index on a non-TTL field?
If a non-TTL single-field index already exists for a field, you cannot create a TTL index on the same field since you cannot create indexes that have the same key specification and differ only by the options. To change a non-TTL single-field index to a TTL index, you must drop the index first and recreate with the expireAfterSeconds option.
When does a TTL Index in MongoDB expire?
TTL indexes expire documents after the specified number of seconds has passed since the indexed field value; i.e. the expiration threshold is the indexed field value plus the specified number of seconds.
Can you create a TTL Index on a capped collection?
You cannot create a TTL index on a capped collection because MongoDB cannot remove documents from a capped collection. You cannot use createIndex () to change the value of expireAfterSeconds of an existing index. Instead use the collMod database command in conjunction with the index collection flag.
When does the TTL background thread delete documents?
On replica set members, the TTL background thread only deletes documents when a member is in state primary. The TTL background thread is idle when a member is in state secondary. Secondary members replicate deletion operations from the primary.