# Record metadata Aerospike record metadata expressions allow you to access and evaluate record-level metadata in queries. This guide covers expressions like `record_size`, `key_exists`, `ttl`, `last_update`, and `since_update`, which return details such as record size, existence, and update times. Code examples show how to use these expressions for efficient filtering and data retrieval. ## Ops #### `device_size` ```python device_size() ``` Description: Deprecated in Database 8.1. Use [`record_size`](https://aerospike.com/docs/develop/expressions/metadata#record_size) instead. Returns the record’s storage size in bytes as an integer. Value is 0 when namespace is configured [`storage-engine memory`](https://aerospike.com/database/reference/config#namespace__storage-engine). Returns: `integer_value` Introduced: 5.2.0.4 Example: Find records that occupy more than 1 MiB of storage space. - [c](#tab-panel-591) - [java](#tab-panel-592) ```c as_exp_build(predexp, as_exp_gt(as_exp_device_size(), as_exp_int(1024 * 1024))); ``` ```java Expression exp = Exp.build( Exp.gt(Exp.deviceSize(), Exp.val(1024 * 1024))); ``` --- #### `digest_modulo` ```python digest_modulo(mod) ``` Description: Returns a record digest modulo as an integer. Arguments: | Name | Type | | --- | --- | | `mod` | `integer_value` | Returns: `integer_value` Introduced: 5.2.0.4 Example: Sample records where digest mod 3 equals 0 - [c](#tab-panel-593) - [java](#tab-panel-594) ```c as_exp_build(predexp, as_exp_cmp_eq(as_exp_digest_modulo(3), as_exp_int(0))); ``` ```java Expression exp = Exp.build( Exp.eq(Exp.digestModulo(3), Exp.val(0))); ``` --- #### `is_tombstone` ```python is_tombstone() ``` Description: Returns `true` if the record is a tombstone, otherwise it returns `false`. **Note:** Only applies to XDR filters and when used in a write request with a read/write expressions. Returns: `boolean_value` Introduced: 5.2.0.4 Example: Create an XDR filter to only ship tombstones. - [c](#tab-panel-595) - [java](#tab-panel-596) ```c as_exp_build(predexp, as_exp_is_tombstone()); ``` ```java Expression exp = Exp.build(Exp.isTombstone()); ``` --- #### `key_exists` ```python key_exists() ``` Description: “Returns `true` if the record has a stored key, otherwise it returns `false`.” Returns: `boolean_value` Introduced: 5.2.0.4 Example: Return all records that have a stored key. - [c](#tab-panel-597) - [java](#tab-panel-598) ```c as_exp_build(predexp, as_exp_key_exists()); ``` ```java Expression exp = Exp.build(Exp.keyExists()); ``` --- #### `last_update` ```python last_update() ``` Description: Returns the record’s last-update-time (LUT) in nanoseconds (millisecond resolution) from Unix Epoch (1/1/1970) as an integer. Returns: `integer_value` Introduced: 5.2.0.4 Example: Return all records where the last-update-time is less than bin ‘updateBy’. - [c](#tab-panel-599) - [java](#tab-panel-600) ```c as_exp_build(predexp, as_exp_cmp_lt( as_exp_last_update(), as_exp_bin_int("updateby")));; ``` ```java Expression exp = Exp.build( Exp.lt(Exp.lastUpdate(), Exp.intBin("updateBy"))); ``` --- #### `memory_size` ```python memory_size() ``` Description: Deprecated in Database 8.1. Use [`record_size`](https://aerospike.com/docs/develop/expressions/metadata#record_size) instead. Returns the record’s size in bytes as an integer when the namespace is configured [`storage-engine memory`](https://aerospike.com/docs/database/reference/config#namespace__storage-engine), otherwise returns 0. Prior to Database 7.0: Returns the record’s memory size in bytes as an integer when either the namespace is configured [`data-in-memory true`](https://aerospike.com/docs/database/reference/config#namespace__data-in-memory) or \[`storage-engine memory`\](/database/reference/config#namespace\_\_storage-engine”, otherwise returns 0. Note: deprecated as of Database 7.0.0 since the `data-size` and `memory-size` are now the same size. Use [`record_size`](#record_size) instead. Returns: `integer_value` Introduced: 5.3.0 Example: Find records that occupy more than 1 MiB of memory. - [c](#tab-panel-601) - [java](#tab-panel-602) ```c as_exp_build(predexp, as_exp_gt(as_exp_memory_size(), as_exp_int(1024 * 1024))); ``` ```java Expression exp = Exp.build( Exp.gt(Exp.memorySize(), Exp.val(1024 * 1024))); ``` --- #### `record_size` ```python record_size() ``` Description: Returns the record’s size in bytes as an integer. This is the physical size of the record in the namespace storage device. If compression is turned on, the record size reflects the compressed size of the record, not the logical uncompressed size. Returns: `integer_value` Introduced: 7.0.0 Example: Find records that occupy more than 1 MiB of memory. - [c](#tab-panel-603) - [java](#tab-panel-604) ```c as_exp_build(predexp, as_exp_gt(as_exp_record_size(), as_exp_int(1024 * 1024))); ``` ```java Expression exp = Exp.build( Exp.gt(Exp.recordSize(), Exp.val(1024 * 1024))); ``` --- #### `set_name` ```python set_name() ``` Description: Returns the record’s set\_name as a string. Returns: `string_value` Introduced: 5.2.0.4 Example: Return all records where the set\_name is either ‘groupA’ or ‘groupB’. - [c](#tab-panel-605) - [java](#tab-panel-606) ```c as_exp_build(predexp, as_exp_or( as_exp_cmp_eq(as_exp_set_name(), as_exp_str("groupA")), as_exp_cmp_eq(as_exp_set_name(), as_exp_str("groupB")))); ``` ```java Expression exp = Exp.build(Exp.or( Exp.eq(Exp.setName(), Exp.val("groupA")), Exp.eq(Exp.setName(), Exp.val("groupB")))); ``` --- #### `since_update` ```python since_update() ``` Description: Returns the time (in milliseconds) since the record was last updated. Returns: `integer_value` Introduced: 5.2.0.4 Example: Return records that were updated within the last 2 hours. - [c](#tab-panel-607) - [java](#tab-panel-608) ```c as_exp_build(predexp, as_exp_cmp_lt( as_exp_since_update(), as_exp_int(2 * 60 * 60 * 1000)));; ``` ```java Expression exp = Exp.build( Exp.lt(Exp.sinceUpdate(), Exp.val(2 * 60 * 60 * 1000))); ``` --- #### `ttl` ```python ttl() ``` Description: Returns the record’s TTL (Time To Live) as an integer. Returns: `integer_value` Introduced: 5.2.0.4 Example: Return all records that will expire within 24 hours. - [c](#tab-panel-609) - [java](#tab-panel-610) ```c as_exp_build(predexp, as_exp_cmp_le(as_exp_ttl(), as_exp_int(24 * 60 * 60))); ``` ```java Expression exp = Exp.build( Exp.le(Exp.ttl(), Exp.val(24 * 60 * 60))); ``` --- #### `void_time` ```python void_time() ``` Description: Returns the record’s expiration time in nanoseconds (resolution in seconds) as an integer. Returns: `integer_value` Introduced: 5.2.0.4 Example: Return all records where the void-time is set to ‘never expire’. - [c](#tab-panel-611) - [java](#tab-panel-612) ```c as_exp_build(predexp, as_exp_cmp_eq(as_exp_void_time(), as_exp_int(-1))) ``` ```java Expression exp = Exp.build(Exp.eq(Exp.voidTime(), Exp.val(-1))); ``` ---