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In order to execute a scan using the Scan API, an as_scan object must be initialized and populated.
Before using an as_scan, it must be initialized via either:
as_scan_init() should be used on a stack allocated as_scan. It will initialize the as_scan with the given namespace and set. On success, it will return a pointer to the initialized as_scan. Otherwise, NULL is returned.
as_scan_new() should be used to allocate and initialize a heap allocated as_scan. It will allocate the as_scan, then initialized it with the given namespace and set. On success, it will return a pointer to the initialized as_scan. Otherwise, NULL is returned.
When you are finished with the as_scan, you can destroy it and associated resources:
An initialized as_scan can be populated with additional fields.
as_scan_select() is used to specify the bins to be selected by the scan. If a scan specifies bins to be selected, then only those bins will be returned. If no bins are selected, then all bins will be returned.
Before adding bins to select, the select structure must be initialized via either:
Both functions are given the number of bins to be selected.
A complete example using as_scan_select_inita()
A scan can return only record meta data, and exclude bins.
A scan can be made to scan all the nodes in parallel
A scan can define the percentage of record in the cluster to be scaned.
To set the priority of the scan, the set as_scan.priority.
The priority of a scan can be defined as either:
AS_SCAN_PRIORITY_AUTOAS_SCAN_PRIORITY_LOWAS_SCAN_PRIORITY_MEDIUMAS_SCAN_PRIORITY_HIGHA UDF can be applied to each record scanned.
To define the UDF for the scan, use as_scan_apply_each().
#include "as_scan.h"
Collaboration diagram for as_scan:Data Fields | |
| as_udf_call | apply_each |
| bool | concurrent |
| bool | deserialize_list_map |
| bool | no_bins |
| as_namespace | ns |
| struct as_operations_s * | ops |
| bool | paginate |
| as_partitions_status * | parts_all |
| as_scan_bins | select |
| as_set | set |
| uint32_t | ttl |
Related Symbols | |
(Note that these are not member symbols.) | |
| AS_EXTERN bool | as_scan_apply_each (as_scan *scan, const char *module, const char *function, as_list *arglist) |
| AS_EXTERN bool | as_scan_compare (as_scan *s1, as_scan *s2) |
| AS_EXTERN void | as_scan_destroy (as_scan *scan) |
| AS_EXTERN bool | as_scan_from_bytes (as_scan *scan, const uint8_t *bytes, uint32_t bytes_size) |
| AS_EXTERN as_scan * | as_scan_from_bytes_new (const uint8_t *bytes, uint32_t bytes_size) |
| AS_EXTERN as_scan * | as_scan_init (as_scan *scan, const char *ns, const char *set) |
| static bool | as_scan_is_done (as_scan *scan) |
| AS_EXTERN as_scan * | as_scan_new (const char *ns, const char *set) |
| AS_EXTERN bool | as_scan_select (as_scan *scan, const char *bin) |
| AS_EXTERN bool | as_scan_select_init (as_scan *scan, uint16_t n) |
| #define | as_scan_select_inita(__scan, __n) |
| AS_EXTERN bool | as_scan_set_concurrent (as_scan *scan, bool concurrent) |
| AS_EXTERN bool | as_scan_set_nobins (as_scan *scan, bool nobins) |
| static void | as_scan_set_paginate (as_scan *scan, bool paginate) |
| static void | as_scan_set_partitions (as_scan *scan, as_partitions_status *parts_all) |
| AS_EXTERN bool | as_scan_to_bytes (const as_scan *scan, uint8_t **bytes, uint32_t *bytes_size) |
|
related |
Initializes as_scan.select with a capacity of n using alloca
For heap allocation, use as_scan_select_init().
| __scan | The scan to initialize. |
| __n | The number of bins to allocate. |
| as_udf_call as_scan::apply_each |
UDF to apply to results of the background scan.
Should be set via as_scan_apply_each().
| bool as_scan::concurrent |
| bool as_scan::deserialize_list_map |
| bool as_scan::no_bins |
| as_namespace ns |
Namespace to be scanned.
Should be initialized via either:
| struct as_operations_s* as_scan::ops |
Perform write operations on a background scan. If ops is set, ops will be destroyed when as_scan_destroy() is called.
| bool as_scan::paginate |
Set to true if as_policy_scan.max_records is set and you need to scan data in pages.
Default: false
| as_partitions_status* as_scan::parts_all |
| as_scan_bins as_scan::select |
Name of bins to select.
Use either of the following function to initialize:
Use as_scan_select() to populate.
| as_set as_scan::set |
Set to be scanned.
Should be initialized via either:
| uint32_t as_scan::ttl |
The time-to-live (expiration) of the record in seconds. Note that ttl is only used on background scan writes.
There are also special values that can be set in the record ttl:
1.10.0 