Queries and mutations

The example stores the people in a database and queries their names. It collects query pages, updates Ada's age, and reads the changed age.

The optional adaptive query planner learns from runs and compares alternative plans for stored queries. Enable it through the database's plugins open option.

Example

The example compares these results:

a committed mutation
a repeated mutation
a query that matches no entity

Give Ada her birthday and read her age

birthday_text holds this document:

json

186 B

{
  "query": {
    "find": [
      "?e"
    ],
    "where": [
      [
        "?e",
        "name",
        "Ada"
      ]
    ]
  },
  "patch": {
    "?e": {
      "age": 37
    }
  }
}

query_text holds this document:

json

150 B

{
  "find": [
    "?age"
  ],
  "where": [
    [
      "?e",
      "name",
      "Ada"
    ],
    [
      "?e",
      "age",
      "?age"
    ]
  ]
}

1.5 kB

stardust_document *birthday = NULL;
stardust_document *definition = NULL;
stardust_db_mutation *mutation = NULL;
stardust_result *committed = NULL;
stardust_db_query *query = NULL;
stardust_db_rows *rows = NULL;
stardust_result *page = NULL;
stardust_document *result = NULL;
uint32_t status = stardust_parse(birthday_text, STARDUST_JSON, &birthday);
if (status == STARDUST_OK) status = stardust_parse(query_text, STARDUST_JSON, &definition);
stardust_db_source change = {.kind = STARDUST_SOURCE_DOCUMENT, .document = birthday};
stardust_db_source source = {.kind = STARDUST_SOURCE_DOCUMENT, .document = definition};
if (status == STARDUST_OK) status = stardust_db_mutation_open(db, &change, &mutation);
if (status == STARDUST_OK) status = stardust_db_mutation_run(mutation, NULL, NULL, NULL, &committed);
if (status == STARDUST_OK) status = stardust_db_query_open(db, &source, &query);
if (status == STARDUST_OK) status = stardust_db_query_run(query, NULL, NULL, NULL, &rows);
if (status == STARDUST_OK) status = stardust_db_rows_next(rows, &page);
if (status == STARDUST_OK) status = stardust_result_take_document(page, &result);
stardust_result_release(page);
stardust_db_rows_release(rows);
stardust_db_query_release(query);
stardust_result_release(committed);
stardust_db_mutation_release(mutation);
stardust_document_release(definition);
stardust_document_release(birthday);
if (status != STARDUST_OK) {stardust_document_release(result); return status;}

Result / 25 B

[
  {
    "age": 37
  }
]

Query pages

Each query page is an owned document.

You can keep a page after you release the rows handle, query, or database that produced it.
Release each page when you finish with its values. The document ownership rule applies.

The database can keep completed native fact joins as owned binding rows before aggregation. When you run the same query and plan again, the cache can supply those rows at the same database snapshot. Aggregates and output expressions still run for each call.

The cache uses the database working-memory budget and gives memory back when queries need it. The cache discards rows from joins that do not complete. After a write, new queries use a new snapshot. An active reader keeps the rows from its original snapshot.

Parameterized, temporal and overlay queries use their normal execution paths. Queries with predicates, derivations, member clauses or transaction terms also use those paths. Background planner trials and sampled foreground measurements execute joins directly.

Exact indexes

A query or mutation definition that compares a field with a value makes the database build that field's exact index. The comparison is a fact clause with a constant or a parameter value, or a =, <, <=, >, >= or hasPrefix predicate on a fact clause's value. With the index, a hasPrefix predicate reads only the texts that start with the prefix, and no value of another type.

Storing the definition starts the build. An inline query or mutation that compares a field the same way also starts one.
The database builds the index in the background, including the values committed before the definition. The call that started it does not wait.
Queries scan the field until its index is ready. The results are the same; only the time differs.
Use indexes_sync to wait until every index that earlier definitions and inline runs ask for is ready, for example before you measure a query.
An index that no definition uses any more stays until the database next opens.

Operations

Operation	Returns	Summary
stardust_db_read_entity	Status. document through output	database.read_entity(entity, max_depth, max_entities) atomically returns an owned {document links revisions truncated} document, expanding links up to max_depth hops.
stardust_db_query_open	Status. query through output	Open an owned query from a path or an inline definition.
stardust_db_mutation_open	Status. mutation through output	Open an owned mutation from a path or an inline definition.
stardust_db_query_run	Status. rows through output	Run the query and return an owned row cursor.
stardust_db_query_release	`void`	Release the query handle.
stardust_db_rows_next	Status. document through output	Read the next page as an owned document.
pages	Unavailable	rows.pages() iterates the non-empty pages of the cursor.
all_pages	Unavailable	rows.all_pages() reads every remaining page into one owned array document.
stardust_db_rows_release	`void`	Release the rows handle.
stardust_db_query_subscribe	Status. subscription through output	query.subscribe(parameters, options) opens an owned live subscription.
stardust_db_subscription_next	Status. event through output	Wait for the next live event.
events	Unavailable	subscription.events() delivers events in order until the subscription is cancelled, closes or fails.
stardust_db_subscription_cancel	`void`	subscription.cancel() ends the subscription.
stardust_db_subscription_release	`void`	Release the subscription handle.
stardust_db_mutation_run	Status. commit through output	Run the mutation and return commit information.
stardust_db_mutation_release	`void`	Release the mutation handle.
stardust_db_merge_patch	Status. commit through output	database.merge_patch(patch) applies an entity-keyed patch document in one transaction and returns commit information.
stardust_db_indexes_sync	Status. none through output	database.indexes_sync(max_wait) waits until the database built every exact index that earlier definition commits and inline runs ask for.
stardust_db_bulk_begin	Status. none through output	database.bulk_begin() starts a bulk build of data merge patches held by the database.
stardust_db_bulk_add	Status. none through output	database.bulk_add(patch) copies and queues one merge-patch document in the bulk build.
stardust_db_bulk_finish	Status. document through output	database.bulk_finish() publishes the bulk build with one commit, ends it and returns an owned summary document.
stardust_db_bulk_abort	`void`	database.bulk_abort() drops the bulk build in progress without writing it.
stardust_db_subscription_set_notify	status	Wake a host scheduler when a subscription may be ready.

stardust_db_read_entity

133 B

uint32_t stardust_db_read_entity(stardust_db *db, int64_t entity, int64_t max_depth, int64_t max_entities, stardust_result **output);

92 B

uint32_t stardust_result_take_document(stardust_result *result, stardust_document **output);

96 B

uint32_t stardust_result_error(const stardust_result *result, stardust_diagnostic_view *output);

54 B

void stardust_result_release(stardust_result *result);

Parameters

stardust_db_read_entity

Parameter	Type	Ownership	Default	Meaning
`db`	`stardust_db *`	Borrowed handle	Required	Keep the handle alive until the call returns.
`entity`	`int64_t`	Value	Required	The decimal user entity ID.
`max_depth`	`int64_t`	Value	Required	Link hops to expand along each path, 0 through 32. 0, the default, leaves every link a {#link id} reference.
`max_entities`	`int64_t`	Value	Required	The most entity documents the result holds, counting the root and every expanded or absent target each time it is placed. 0 selects the default of 1000.
`output`	`stardust_result **`	Owned output	Required	Receives a library-owned handle. Release it after use.

stardust_result_take_document

Parameter	Type	Ownership	Default	Meaning
`result`	`stardust_result *`	Borrowed handle	Required	Keep the handle alive until the call returns.
`output`	`stardust_document **`	Owned output	Required	Receives a library-owned handle. Release it after use.

stardust_result_error

Parameter	Type	Ownership	Default	Meaning
`result`	`const stardust_result *`	Borrowed handle	Required	Keep the handle alive until the call returns.
`output`	`stardust_diagnostic_view *`	Caller-owned output	Required	Receives a record. Its pointer fields follow the record's ownership contract.

stardust_result_release

Parameter	Type	Ownership	Default	Meaning
`result`	`stardust_result *`	Consumed handle	NULL	Ends ownership. Do not use the handle after this call.

Errors

Status	When
`STARDUST_INVALID_ARGUMENT`	the entity ID is outside the user entity range, `max_depth` is negative or above 32, or `max_entities` is negative
`STARDUST_CLOSED`	the database is closed
`STARDUST_OUT_OF_MEMORY`	native memory is exhausted

Notes

revisions maps each placed entity's decimal ID to its last-touch transaction for #_tx.stardust/checkAndSet. Empty object and array fields are omitted recursively. See entity reads for result fields, JSON Pointer links and expansion rules.

Examples

Read Bob with his mentor expanded

330 B

stardust_document *result = NULL;
stardust_result *outcome = NULL;
uint32_t status = stardust_db_read_entity(db, 2, 1, 0, &outcome);
if (status == STARDUST_OK) status = stardust_result_take_document(outcome, &result);
stardust_result_release(outcome);
if (status != STARDUST_OK) {stardust_document_release(result); return status;}

Result / 291 B

{
  "document": {
    "age": 41,
    "mentor": {
      "age": 36,
      "name": "Ada",
      "role": "engineer"
    },
    "name": "Bob",
    "role": "engineer"
  },
  "links": {
    "/mentor": {
      "#link": 1
    }
  },
  "revisions": {
    "1": 4,
    "2": 4
  },
  "truncated": false
}

Also calls: stardust_result_take_document, stardust_result_error, stardust_result_release

stardust_db_query_open

111 B

uint32_t stardust_db_query_open(stardust_db *db, const stardust_db_source *source, stardust_db_query **output);

100 B

uint32_t stardust_db_query_error(const stardust_db_query *handle, stardust_diagnostic_view *output);

Parameters

stardust_db_query_open

Parameter	Type	Ownership	Default	Meaning
`db`	`stardust_db *`	Borrowed handle	Required	Keep the handle alive until the call returns.
`source`	`const stardust_db_source *`	Borrowed input	Required	An inline native definition or a stored definition path.
`output`	`stardust_db_query **`	Owned output	Required	Receives a library-owned handle. Release it after use.

stardust_db_query_error

Parameter	Type	Ownership	Default	Meaning
`handle`	`const stardust_db_query *`	Borrowed handle	Required	Keep the handle alive until the call returns.
`output`	`stardust_diagnostic_view *`	Caller-owned output	Required	Receives a record. Its pointer fields follow the record's ownership contract.

Errors

Status	When
`STARDUST_NOT_FOUND`	no definition is stored at the path
`STARDUST_INVALID_DEFINITION`	the definition is invalid
`STARDUST_CLOSED`	the database is closed
`STARDUST_OUT_OF_MEMORY`	native memory is exhausted
`STARDUST_INVALID_ARGUMENT`	a required input or output pointer is NULL, or an input owner is not ready

Notes

Inline definitions are copied. Stored paths select their definition at run time.

Query documents.

Examples

Open an inline query and read its first page

query_text holds this document:

json

134 B

{
  "find": [
    "?name"
  ],
  "where": [
    [
      "?e",
      "name",
      "?name"
    ]
  ],
  "orderBy": [
    "?name"
  ]
}

868 B

stardust_document *definition = NULL;
stardust_db_query *query = NULL;
stardust_db_rows *rows = NULL;
stardust_result *page = NULL;
stardust_document *result = NULL;
uint32_t status = stardust_parse(query_text, STARDUST_JSON, &definition);
stardust_db_source source = {.kind = STARDUST_SOURCE_DOCUMENT, .document = definition};
if (status == STARDUST_OK) status = stardust_db_query_open(db, &source, &query);
if (status == STARDUST_OK) status = stardust_db_query_run(query, NULL, NULL, NULL, &rows);
if (status == STARDUST_OK) status = stardust_db_rows_next(rows, &page);
if (status == STARDUST_OK) status = stardust_result_take_document(page, &result);
stardust_result_release(page);
stardust_db_rows_release(rows);
stardust_db_query_release(query);
stardust_document_release(definition);
if (status != STARDUST_OK) {stardust_document_release(result); return status;}

Result / 82 B

[
  {
    "name": "Ada"
  },
  {
    "name": "Bob"
  },
  {
    "name": "Cy"
  }
]

Refuse an invalid query definition

definition_text holds this document:

json

29 B

{
  "find": [
    "?x"
  ]
}

496 B

stardust_document *definition = NULL;
uint32_t status = stardust_parse(definition_text, STARDUST_JSON, &definition);
if (status != STARDUST_OK) {stardust_document_release(definition); return status;}
stardust_db_source source = {.kind = STARDUST_SOURCE_DOCUMENT, .document = definition};
stardust_db_query *failed = NULL;
status = stardust_db_query_open(db, &source, &failed);
stardust_document_release(definition);
stardust_diagnostic_view result = {0};
stardust_db_query_error(failed, &result);

Result / 168 B

{
  "code": "unbound_variable",
  "message": "Unbound_Variable",
  "path": null,
  "field": null,
  "entity": null,
  "offset": null,
  "status": "invalid_definition"
}

Report a missing stored query

287 B

stardust_db_source source = {.kind = STARDUST_SOURCE_PATH, .path = {(const uint8_t *)"people/missing", 14}};
stardust_db_query *failed = NULL;
uint32_t status = stardust_db_query_open(db, &source, &failed);
stardust_diagnostic_view result = {0};
stardust_db_query_error(failed, &result);

Result / 174 B

{
  "code": "not_found",
  "message": "no definition at this path",
  "path": "people/missing",
  "field": null,
  "entity": null,
  "offset": null,
  "status": "not_found"
}

Also calls: stardust_db_query_error

stardust_db_mutation_open

117 B

uint32_t stardust_db_mutation_open(stardust_db *db, const stardust_db_source *source, stardust_db_mutation **output);

106 B

uint32_t stardust_db_mutation_error(const stardust_db_mutation *handle, stardust_diagnostic_view *output);

Parameters

stardust_db_mutation_open

Parameter	Type	Ownership	Default	Meaning
`db`	`stardust_db *`	Borrowed handle	Required	Keep the handle alive until the call returns.
`source`	`const stardust_db_source *`	Borrowed input	Required	An inline native definition or a stored definition path.
`output`	`stardust_db_mutation **`	Owned output	Required	Receives a library-owned handle. Release it after use.

stardust_db_mutation_error

Parameter	Type	Ownership	Default	Meaning
`handle`	`const stardust_db_mutation *`	Borrowed handle	Required	Keep the handle alive until the call returns.
`output`	`stardust_diagnostic_view *`	Caller-owned output	Required	Receives a record. Its pointer fields follow the record's ownership contract.

Errors

Status	When
`STARDUST_NOT_FOUND`	no definition is stored at the path
`STARDUST_INVALID_DEFINITION`	the definition is invalid
`STARDUST_CLOSED`	the database is closed
`STARDUST_OUT_OF_MEMORY`	native memory is exhausted
`STARDUST_INVALID_ARGUMENT`	a required input or output pointer is NULL, or an input owner is not ready

Notes

Inline definitions are copied. Stored paths select their definition at run time.

Mutation documents.

Examples

database/mutation

birthday_text holds this document:

json

186 B

{
  "query": {
    "find": [
      "?e"
    ],
    "where": [
      [
        "?e",
        "name",
        "Ada"
      ]
    ]
  },
  "patch": {
    "?e": {
      "age": 37
    }
  }
}

615 B

stardust_document *definition = NULL;
stardust_db_mutation *mutation = NULL;
stardust_result *result = NULL;
uint32_t status = stardust_parse(birthday_text, STARDUST_JSON, &definition);
stardust_db_source source = {.kind = STARDUST_SOURCE_DOCUMENT, .document = definition};
if (status == STARDUST_OK) status = stardust_db_mutation_open(db, &source, &mutation);
if (status == STARDUST_OK) status = stardust_db_mutation_run(mutation, NULL, NULL, NULL, &result);
stardust_db_mutation_release(mutation);
stardust_document_release(definition);
if (status != STARDUST_OK) {stardust_result_release(result); return status;}

Result / 111 B

{
  "status": "committed",
  "transaction": 5,
  "facts": 1,
  "committed_at": 17923367930692901,
  "ids": {}
}

Also calls: stardust_db_mutation_error

stardust_db_query_run

206 B

uint32_t stardust_db_query_run(stardust_db_query *query_handle, const stardust_document *parameters, const stardust_db_query_options *options, stardust_db_query_explain *explain, stardust_db_rows **output);

96 B

uint32_t stardust_db_rows_error(const stardust_db_rows *rows, stardust_diagnostic_view *output);

Parameters

stardust_db_query_run

Parameter	Type	Ownership	Default	Meaning
`query_handle`	`stardust_db_query *`	Borrowed handle	Required	Keep the handle alive until the call returns.
`parameters`	`const stardust_document *`	Borrowed handle	NULL	An optional object of parameter values that merge-patches the definition's declared parameters. A parameter matched in the entity position of a fact clause takes an entity reference {#link id}, never the bare ID number: a commit returns IDs as numbers, so wrap one as {#link id}, or as the typed Link value where the binding has one, before passing it. A query run fails with `entity_reference_expected` when a bare number reaches that position. Projected and found entities also read back as {#link id}, so a typed field that receives one uses Link rather than a plain integer.
`options`	`const stardust_db_query_options *`	Borrowed input	NULL	The operation's options record. See its field defaults.
`explain`	`stardust_db_query_explain *`	Caller-owned output	NULL	Receives a record. Its pointer fields follow the record's ownership contract.
`output`	`stardust_db_rows **`	Owned output	Required	Receives a library-owned handle. Release it after use.

stardust_db_rows_error

Parameter	Type	Ownership	Default	Meaning
`rows`	`const stardust_db_rows *`	Borrowed handle	Required	Keep the handle alive until the call returns.
`output`	`stardust_diagnostic_view *`	Caller-owned output	Required	Receives a record. Its pointer fields follow the record's ownership contract.

Errors

Status	When
`STARDUST_NOT_FOUND`	the stored query definition was deleted
`STARDUST_INVALID_DEFINITION`	the loaded query definition is invalid
`STARDUST_INVALID_ARGUMENT`	the parameters or run options are invalid
`STARDUST_EVALUATION_FAILED`	the query fails or exceeds `max_cost`
`STARDUST_CLOSED`	the parent database is closed
`STARDUST_OUT_OF_MEMORY`	native memory is exhausted

Notes

Query documents.

Examples

Open an inline query and read its first page

query_text holds this document:

json

134 B

{
  "find": [
    "?name"
  ],
  "where": [
    [
      "?e",
      "name",
      "?name"
    ]
  ],
  "orderBy": [
    "?name"
  ]
}

868 B

stardust_document *definition = NULL;
stardust_db_query *query = NULL;
stardust_db_rows *rows = NULL;
stardust_result *page = NULL;
stardust_document *result = NULL;
uint32_t status = stardust_parse(query_text, STARDUST_JSON, &definition);
stardust_db_source source = {.kind = STARDUST_SOURCE_DOCUMENT, .document = definition};
if (status == STARDUST_OK) status = stardust_db_query_open(db, &source, &query);
if (status == STARDUST_OK) status = stardust_db_query_run(query, NULL, NULL, NULL, &rows);
if (status == STARDUST_OK) status = stardust_db_rows_next(rows, &page);
if (status == STARDUST_OK) status = stardust_result_take_document(page, &result);
stardust_result_release(page);
stardust_db_rows_release(rows);
stardust_db_query_release(query);
stardust_document_release(definition);
if (status != STARDUST_OK) {stardust_document_release(result); return status;}

Result / 82 B

[
  {
    "name": "Ada"
  },
  {
    "name": "Bob"
  },
  {
    "name": "Cy"
  }
]

Capture the host duration boundary

query_text holds this document:

json

134 B

{
  "find": [
    "?name"
  ],
  "where": [
    [
      "?e",
      "name",
      "?name"
    ]
  ],
  "orderBy": [
    "?name"
  ]
}

boundary_text holds this document:

json

20 B

9223372036854775807

1.1 kB

stardust_document *definition = NULL;
stardust_db_query *query = NULL;
stardust_db_rows *rows = NULL;
stardust_document *boundary = NULL;
uint32_t boundary_root = 0;
int64_t ticks = 0;
uint32_t status = stardust_parse(boundary_text, STARDUST_JSON, &boundary);
if (status == STARDUST_OK) status = stardust_document_root(boundary, &boundary_root);
if (status == STARDUST_OK) status = stardust_document_i64(boundary, boundary_root, &ticks);
stardust_document_release(boundary);
if (status == STARDUST_OK) status = stardust_parse(query_text, STARDUST_JSON, &definition);
stardust_db_source source = {.kind = STARDUST_SOURCE_DOCUMENT, .document = definition};
stardust_db_query_options result = {.size=sizeof(result), .version=1, .page_size=2, .max_cost_ticks=ticks};
if (status == STARDUST_OK) status = stardust_db_query_open(db, &source, &query);
if (status == STARDUST_OK) status = stardust_db_query_run(query, NULL, &result, NULL, &rows);
stardust_db_rows_release(rows);
stardust_db_query_release(query);
stardust_document_release(definition);
if (status != STARDUST_OK) return status;

Result / 69 B

{
  "page_size": 2,
  "max_cost": 9223372036854775807,
  "as_of": 0
}

The C ABI takes complete 100-ns ticks

query_text holds this document:

json

134 B

{
  "find": [
    "?name"
  ],
  "where": [
    [
      "?e",
      "name",
      "?name"
    ]
  ],
  "orderBy": [
    "?name"
  ]
}

532 B

stardust_document *definition = NULL;
stardust_db_query *query = NULL;
uint32_t status = stardust_parse(query_text, STARDUST_JSON, &definition);
stardust_db_source source = {.kind = STARDUST_SOURCE_DOCUMENT, .document = definition};
stardust_db_query_options result = {.size=sizeof(result), .version=1, .page_size=2, .max_cost_ticks=1};
if (status == STARDUST_OK) status = stardust_db_query_open(db, &source, &query);
stardust_db_query_release(query);
stardust_document_release(definition);
if (status != STARDUST_OK) return status;

Result / 51 B

{
  "page_size": 2,
  "max_cost": 1,
  "as_of": 0
}

Explain query execution

query_text holds this document:

json

134 B

{
  "find": [
    "?name"
  ],
  "where": [
    [
      "?e",
      "name",
      "?name"
    ]
  ],
  "orderBy": [
    "?name"
  ]
}

671 B

stardust_document *definition = NULL;
stardust_db_query *query = NULL;
stardust_db_rows *rows = NULL;
stardust_db_query_explain explain = {0};
uint32_t status = stardust_parse(query_text, STARDUST_JSON, &definition);
stardust_db_source source = {.kind = STARDUST_SOURCE_DOCUMENT, .document = definition};
if (status == STARDUST_OK) status = stardust_db_query_open(db, &source, &query);
if (status == STARDUST_OK) status = stardust_db_query_run(query, NULL, NULL, &explain, &rows);
stardust_db_rows_release(rows);
stardust_db_query_release(query);
stardust_document_release(definition);
if (status != STARDUST_OK) return status;
stardust_db_query_explain result = explain;

Result / 670 B

{
  "load_definition": {
    "cpu": 1870,
    "wall": 1878,
    "arena_bytes": 1680
  },
  "parameters": {
    "cpu": 8,
    "wall": 10,
    "arena_bytes": 0
  },
  "run": {
    "cpu": 8937,
    "wall": 8968,
    "arena_bytes": 7424
  },
  "total": {
    "cpu": 10842,
    "wall": 10883,
    "arena_bytes": 9104
  },
  "arena_capacity": 4194304,
  "work": 5761,
  "rows": 3,
  "compile": 372,
  "plan": 517,
  "execute": 0,
  "group": 0,
  "order": 0,
  "memory_bytes": 5995,
  "memory_refusals": 0,
  "budget_bytes": 10489856512,
  "budget_used_bytes": 10194,
  "budget_peak_bytes": 14267,
  "budget_refusals": 0,
  "retry": 0,
  "stages_completed": 3,
  "retries": 0
}

A negative configured duration is not an absent field

90 B

stardust_db_query_options result = {.size=sizeof(result), .version=1, .max_cost_ticks=-1};

Result / 52 B

{
  "page_size": 0,
  "max_cost": -1,
  "as_of": 0
}

Run with typed query options

query_text holds this document:

json

134 B

{
  "find": [
    "?name"
  ],
  "where": [
    [
      "?e",
      "name",
      "?name"
    ]
  ],
  "orderBy": [
    "?name"
  ]
}

713 B

stardust_document *definition = NULL;
stardust_db_query *query = NULL;
stardust_db_rows *rows = NULL;
uint32_t status = stardust_parse(query_text, STARDUST_JSON, &definition);
stardust_db_source source = {.kind = STARDUST_SOURCE_DOCUMENT, .document = definition};
stardust_db_query_options result = {.size=sizeof(result), .version=1, .page_size=2, .max_cost_ticks=STARDUST_TICKS_PER_SECOND};
if (status == STARDUST_OK) status = stardust_db_query_open(db, &source, &query);
if (status == STARDUST_OK) status = stardust_db_query_run(query, NULL, &result, NULL, &rows);
stardust_db_rows_release(rows);
stardust_db_query_release(query);
stardust_document_release(definition);
if (status != STARDUST_OK) return status;

Result / 58 B

{
  "page_size": 2,
  "max_cost": 10000000,
  "as_of": 0
}

Also calls: stardust_db_rows_error

stardust_db_query_release

64 B

void stardust_db_query_release(stardust_db_query *query_handle);

Consumes the receiver handle.

Parameters

Parameter	Type	Ownership	Default	Meaning
`query_handle`	`stardust_db_query *`	Consumed handle	NULL	Ends ownership. Do not use the handle after this call.

Examples

Open an inline query and read its first page

query_text holds this document:

json

134 B

{
  "find": [
    "?name"
  ],
  "where": [
    [
      "?e",
      "name",
      "?name"
    ]
  ],
  "orderBy": [
    "?name"
  ]
}

868 B

stardust_document *definition = NULL;
stardust_db_query *query = NULL;
stardust_db_rows *rows = NULL;
stardust_result *page = NULL;
stardust_document *result = NULL;
uint32_t status = stardust_parse(query_text, STARDUST_JSON, &definition);
stardust_db_source source = {.kind = STARDUST_SOURCE_DOCUMENT, .document = definition};
if (status == STARDUST_OK) status = stardust_db_query_open(db, &source, &query);
if (status == STARDUST_OK) status = stardust_db_query_run(query, NULL, NULL, NULL, &rows);
if (status == STARDUST_OK) status = stardust_db_rows_next(rows, &page);
if (status == STARDUST_OK) status = stardust_result_take_document(page, &result);
stardust_result_release(page);
stardust_db_rows_release(rows);
stardust_db_query_release(query);
stardust_document_release(definition);
if (status != STARDUST_OK) {stardust_document_release(result); return status;}

Result / 82 B

[
  {
    "name": "Ada"
  },
  {
    "name": "Bob"
  },
  {
    "name": "Cy"
  }
]

stardust_db_rows_next

79 B

uint32_t stardust_db_rows_next(stardust_db_rows *rows, stardust_result **page);

92 B

uint32_t stardust_result_take_document(stardust_result *result, stardust_document **output);

96 B

uint32_t stardust_result_error(const stardust_result *result, stardust_diagnostic_view *output);

54 B

void stardust_result_release(stardust_result *result);

Parameters

stardust_db_rows_next

Parameter	Type	Ownership	Default	Meaning
`rows`	`stardust_db_rows *`	Borrowed handle	Required	Keep the handle alive until the call returns.
`page`	`stardust_result **`	Owned output	Required	Receives a library-owned handle. Release it after use.

stardust_result_take_document

Parameter	Type	Ownership	Default	Meaning
`result`	`stardust_result *`	Borrowed handle	Required	Keep the handle alive until the call returns.
`output`	`stardust_document **`	Owned output	Required	Receives a library-owned handle. Release it after use.

stardust_result_error

Parameter	Type	Ownership	Default	Meaning
`result`	`const stardust_result *`	Borrowed handle	Required	Keep the handle alive until the call returns.
`output`	`stardust_diagnostic_view *`	Caller-owned output	Required	Receives a record. Its pointer fields follow the record's ownership contract.

stardust_result_release

Parameter	Type	Ownership	Default	Meaning
`result`	`stardust_result *`	Consumed handle	NULL	Ends ownership. Do not use the handle after this call.

Errors

Status	When
`STARDUST_EVALUATION_FAILED`	the page does not render
`STARDUST_CLOSED`	the parent database is closed
`STARDUST_OUT_OF_MEMORY`	native memory is exhausted
`STARDUST_INVALID_ARGUMENT`	a required input or output pointer is NULL, or an input owner is not ready

Notes

An empty array ends the cursor. Every page reads the snapshot selected by the run. Returned pages survive cursor and database closure.

Examples

Open an inline query and read its first page

query_text holds this document:

json

134 B

{
  "find": [
    "?name"
  ],
  "where": [
    [
      "?e",
      "name",
      "?name"
    ]
  ],
  "orderBy": [
    "?name"
  ]
}

868 B

stardust_document *definition = NULL;
stardust_db_query *query = NULL;
stardust_db_rows *rows = NULL;
stardust_result *page = NULL;
stardust_document *result = NULL;
uint32_t status = stardust_parse(query_text, STARDUST_JSON, &definition);
stardust_db_source source = {.kind = STARDUST_SOURCE_DOCUMENT, .document = definition};
if (status == STARDUST_OK) status = stardust_db_query_open(db, &source, &query);
if (status == STARDUST_OK) status = stardust_db_query_run(query, NULL, NULL, NULL, &rows);
if (status == STARDUST_OK) status = stardust_db_rows_next(rows, &page);
if (status == STARDUST_OK) status = stardust_result_take_document(page, &result);
stardust_result_release(page);
stardust_db_rows_release(rows);
stardust_db_query_release(query);
stardust_document_release(definition);
if (status != STARDUST_OK) {stardust_document_release(result); return status;}

Result / 82 B

[
  {
    "name": "Ada"
  },
  {
    "name": "Bob"
  },
  {
    "name": "Cy"
  }
]

Also calls: stardust_result_take_document, stardust_result_error, stardust_result_release

pages

Call stardust_db_rows_next until a page root has no first child.

Also calls: stardust_db_rows_next, stardust_result_take_document, stardust_result_error, stardust_result_release, stardust_document_root, stardust_document_read_many, stardust_document_release

all_pages

Copy each page's rows into one stardust_document_builder_add_many array.

Also calls: stardust_db_rows_next, stardust_result_take_document, stardust_result_error, stardust_result_release, stardust_document_count, stardust_document_read_many, stardust_document_i64, stardust_document_f64, stardust_document_release, stardust_document_builder_create, stardust_document_builder_add_many, stardust_document_builder_seal, stardust_document_builder_release

stardust_db_rows_release

54 B

void stardust_db_rows_release(stardust_db_rows *rows);

Consumes the receiver handle.

Parameters

Parameter	Type	Ownership	Default	Meaning
`rows`	`stardust_db_rows *`	Consumed handle	NULL	Ends ownership. Do not use the handle after this call.

Examples

Open an inline query and read its first page

query_text holds this document:

json

134 B

{
  "find": [
    "?name"
  ],
  "where": [
    [
      "?e",
      "name",
      "?name"
    ]
  ],
  "orderBy": [
    "?name"
  ]
}

868 B

stardust_document *definition = NULL;
stardust_db_query *query = NULL;
stardust_db_rows *rows = NULL;
stardust_result *page = NULL;
stardust_document *result = NULL;
uint32_t status = stardust_parse(query_text, STARDUST_JSON, &definition);
stardust_db_source source = {.kind = STARDUST_SOURCE_DOCUMENT, .document = definition};
if (status == STARDUST_OK) status = stardust_db_query_open(db, &source, &query);
if (status == STARDUST_OK) status = stardust_db_query_run(query, NULL, NULL, NULL, &rows);
if (status == STARDUST_OK) status = stardust_db_rows_next(rows, &page);
if (status == STARDUST_OK) status = stardust_result_take_document(page, &result);
stardust_result_release(page);
stardust_db_rows_release(rows);
stardust_db_query_release(query);
stardust_document_release(definition);
if (status != STARDUST_OK) {stardust_document_release(result); return status;}

Result / 82 B

[
  {
    "name": "Ada"
  },
  {
    "name": "Bob"
  },
  {
    "name": "Cy"
  }
]

184 B

uint32_t stardust_db_query_subscribe(stardust_db_query *query_handle, const stardust_document *parameters, const stardust_db_query_options *options, stardust_db_subscription **output);

111 B

uint32_t stardust_db_subscription_error(const stardust_db_subscription *sub, stardust_diagnostic_view *output);

Parameters

Parameter	Type	Ownership	Default	Meaning
`query_handle`	`stardust_db_query *`	Borrowed handle	Required	Keep the handle alive until the call returns.
`parameters`	`const stardust_document *`	Borrowed handle	NULL	An optional object of parameter values that merge-patches the definition's declared parameters. A parameter matched in the entity position of a fact clause takes an entity reference {#link id}, never the bare ID number: a commit returns IDs as numbers, so wrap one as {#link id}, or as the typed Link value where the binding has one, before passing it. A query run fails with `entity_reference_expected` when a bare number reaches that position. Projected and found entities also read back as {#link id}, so a typed field that receives one uses Link rather than a plain integer.
`options`	`const stardust_db_query_options *`	Borrowed input	NULL	The operation's options record. See its field defaults.
`output`	`stardust_db_subscription **`	Owned output	Required	Receives a library-owned handle. Release it after use.

stardust_db_subscription_error

Parameter	Type	Ownership	Default	Meaning
`sub`	`const stardust_db_subscription *`	Borrowed handle	Required	Keep the handle alive until the call returns.
`output`	`stardust_diagnostic_view *`	Caller-owned output	Required	Receives a record. Its pointer fields follow the record's ownership contract.

Errors

Status	When
`STARDUST_INVALID_DEFINITION`	the query or its callable definitions are invalid
`STARDUST_INVALID_ARGUMENT`	the parameters or subscription options are invalid
`STARDUST_CLOSED`	the parent database is closed
`STARDUST_OUT_OF_MEMORY`	native memory is exhausted

Notes

The subscription copies its definition and parameters. Later definition edits do not change it. The page_size option is ignored.

Blocking next works without registration. To wake your scheduler, see Readiness callbacks for registration, waiting and context lifetime.

Query documents.

Examples

query_text holds this document:

json

134 B

{
  "find": [
    "?name"
  ],
  "where": [
    [
      "?e",
      "name",
      "?name"
    ]
  ],
  "orderBy": [
    "?name"
  ]
}

835 B

stardust_document *definition = NULL;
stardust_db_query *query = NULL;
stardust_db_subscription *subscription = NULL;
stardust_db_live_event event = {0};
uint32_t status = stardust_parse(query_text, STARDUST_JSON, &definition);
stardust_db_source source = {.kind = STARDUST_SOURCE_DOCUMENT, .document = definition};
if (status == STARDUST_OK) status = stardust_db_query_open(db, &source, &query);
if (status == STARDUST_OK) status = stardust_db_query_subscribe(query, NULL, NULL, &subscription);
if (status == STARDUST_OK) status = stardust_db_subscription_next(subscription, 0, &event);
stardust_db_subscription_release(subscription);
stardust_db_query_release(query);
stardust_document_release(definition);
if (status != STARDUST_OK) {stardust_document_release(event.result); return status;}
stardust_document *result = event.result;

Result / 82 B

[
  {
    "name": "Ada"
  },
  {
    "name": "Bob"
  },
  {
    "name": "Cy"
  }
]

Read the complete initial subscription event

query_text holds this document:

json

134 B

{
  "find": [
    "?name"
  ],
  "where": [
    [
      "?e",
      "name",
      "?name"
    ]
  ],
  "orderBy": [
    "?name"
  ]
}

832 B

stardust_document *definition = NULL;
stardust_db_query *query = NULL;
stardust_db_subscription *subscription = NULL;
stardust_db_live_event event = {0};
uint32_t status = stardust_parse(query_text, STARDUST_JSON, &definition);
stardust_db_source source = {.kind = STARDUST_SOURCE_DOCUMENT, .document = definition};
if (status == STARDUST_OK) status = stardust_db_query_open(db, &source, &query);
if (status == STARDUST_OK) status = stardust_db_query_subscribe(query, NULL, NULL, &subscription);
if (status == STARDUST_OK) status = stardust_db_subscription_next(subscription, 0, &event);
stardust_db_subscription_release(subscription);
stardust_db_query_release(query);
stardust_document_release(definition);
if (status != STARDUST_OK) {stardust_document_release(event.result); return status;}
stardust_db_live_event result = event;

Result / 174 B

{
  "sequence": 1,
  "superseded": 0,
  "transaction": 4,
  "result": [
    {
      "name": "Ada"
    },
    {
      "name": "Bob"
    },
    {
      "name": "Cy"
    }
  ]
}

Also calls: stardust_db_subscription_error

stardust_db_subscription_next

125 B

uint32_t stardust_db_subscription_next(stardust_db_subscription *sub, int64_t max_wait_ticks, stardust_db_live_event *event);

111 B

uint32_t stardust_db_subscription_error(const stardust_db_subscription *sub, stardust_diagnostic_view *output);

55 B

void stardust_document_release(stardust_document *doc);

Parameters

stardust_db_subscription_next

Parameter	Type	Ownership	Default	Meaning
`sub`	`stardust_db_subscription *`	Borrowed handle	Required	Keep the handle alive until the call returns.
`max_wait_ticks`	`int64_t`	Value	Required	Value passed to the call.
`event`	`stardust_db_live_event *`	Caller-owned output	Required	Receives a record. Its pointer fields follow the record's ownership contract.

stardust_db_subscription_error

Parameter	Type	Ownership	Default	Meaning
`sub`	`const stardust_db_subscription *`	Borrowed handle	Required	Keep the handle alive until the call returns.
`output`	`stardust_diagnostic_view *`	Caller-owned output	Required	Receives a record. Its pointer fields follow the record's ownership contract.

stardust_document_release

Parameter	Type	Ownership	Default	Meaning
`doc`	`stardust_document *`	Consumed handle	NULL	Ends ownership. Do not use the handle after this call.

Errors

Status	When
`STARDUST_INVALID_ARGUMENT`	`max_wait` is negative
`STARDUST_CANCELLED`	the subscription is cancelled or closed
`STARDUST_EVALUATION_FAILED`	a rerun of the query failed. Every later call reports this failure
`STARDUST_CLOSED`	the parent database is closed
`STARDUST_OUT_OF_MEMORY`	native memory is exhausted

Notes

Each event replaces the entire result. superseded counts skipped computed results, not commits. Cancel, close and database close wake blocked waits. Windows rounds deadlines to milliseconds.

Examples

subscription/next

query_text holds this document:

json

134 B

{
  "find": [
    "?name"
  ],
  "where": [
    [
      "?e",
      "name",
      "?name"
    ]
  ],
  "orderBy": [
    "?name"
  ]
}

835 B

stardust_document *definition = NULL;
stardust_db_query *query = NULL;
stardust_db_subscription *subscription = NULL;
stardust_db_live_event event = {0};
uint32_t status = stardust_parse(query_text, STARDUST_JSON, &definition);
stardust_db_source source = {.kind = STARDUST_SOURCE_DOCUMENT, .document = definition};
if (status == STARDUST_OK) status = stardust_db_query_open(db, &source, &query);
if (status == STARDUST_OK) status = stardust_db_query_subscribe(query, NULL, NULL, &subscription);
if (status == STARDUST_OK) status = stardust_db_subscription_next(subscription, 0, &event);
stardust_db_subscription_release(subscription);
stardust_db_query_release(query);
stardust_document_release(definition);
if (status != STARDUST_OK) {stardust_document_release(event.result); return status;}
stardust_document *result = event.result;

Result / 82 B

[
  {
    "name": "Ada"
  },
  {
    "name": "Bob"
  },
  {
    "name": "Cy"
  }
]

Also calls: stardust_db_subscription_error, stardust_document_release

events

Call stardust_db_subscription_next repeatedly.

Also calls: stardust_db_subscription_next, stardust_db_subscription_error

stardust_db_subscription_cancel

68 B

void stardust_db_subscription_cancel(stardust_db_subscription *sub);

Parameters

Parameter	Type	Ownership	Default	Meaning
`sub`	`stardust_db_subscription *`	Borrowed handle	NULL	Keep the handle alive until the call returns.

Notes

Repeated cancellation is safe. Close the subscription separately to release its handle.

Examples

subscription/cancel

query_text holds this document:

json

134 B

{
  "find": [
    "?name"
  ],
  "where": [
    [
      "?e",
      "name",
      "?name"
    ]
  ],
  "orderBy": [
    "?name"
  ]
}

882 B

stardust_document *definition = NULL;
stardust_db_query *query = NULL;
stardust_db_subscription *subscription = NULL;
stardust_db_live_event event = {0};
uint32_t status = stardust_parse(query_text, STARDUST_JSON, &definition);
stardust_db_source source = {.kind = STARDUST_SOURCE_DOCUMENT, .document = definition};
if (status == STARDUST_OK) status = stardust_db_query_open(db, &source, &query);
if (status == STARDUST_OK) status = stardust_db_query_subscribe(query, NULL, NULL, &subscription);
if (status == STARDUST_OK) status = stardust_db_subscription_next(subscription, 0, &event);
stardust_db_subscription_cancel(subscription);
stardust_db_subscription_release(subscription);
stardust_db_query_release(query);
stardust_document_release(definition);
if (status != STARDUST_OK) {stardust_document_release(event.result); return status;}
stardust_document *result = event.result;

Result / 82 B

[
  {
    "name": "Ada"
  },
  {
    "name": "Bob"
  },
  {
    "name": "Cy"
  }
]

stardust_db_subscription_release

69 B

void stardust_db_subscription_release(stardust_db_subscription *sub);

Consumes the receiver handle.

Parameters

Parameter	Type	Ownership	Default	Meaning
`sub`	`stardust_db_subscription *`	Consumed handle	NULL	Ends ownership. Do not use the handle after this call.

Examples

subscription/close

query_text holds this document:

json

134 B

{
  "find": [
    "?name"
  ],
  "where": [
    [
      "?e",
      "name",
      "?name"
    ]
  ],
  "orderBy": [
    "?name"
  ]
}

835 B

stardust_document *definition = NULL;
stardust_db_query *query = NULL;
stardust_db_subscription *subscription = NULL;
stardust_db_live_event event = {0};
uint32_t status = stardust_parse(query_text, STARDUST_JSON, &definition);
stardust_db_source source = {.kind = STARDUST_SOURCE_DOCUMENT, .document = definition};
if (status == STARDUST_OK) status = stardust_db_query_open(db, &source, &query);
if (status == STARDUST_OK) status = stardust_db_query_subscribe(query, NULL, NULL, &subscription);
if (status == STARDUST_OK) status = stardust_db_subscription_next(subscription, 0, &event);
stardust_db_subscription_release(subscription);
stardust_db_query_release(query);
stardust_document_release(definition);
if (status != STARDUST_OK) {stardust_document_release(event.result); return status;}
stardust_document *result = event.result;

Result / 82 B

[
  {
    "name": "Ada"
  },
  {
    "name": "Bob"
  },
  {
    "name": "Cy"
  }
]

stardust_db_mutation_run

210 B

uint32_t stardust_db_mutation_run(stardust_db_mutation *mutation, const stardust_document *parameters, const stardust_db_write_options *options, stardust_db_mutation_explain *explain, stardust_result **output);

102 B

uint32_t stardust_db_result_commit_info(const stardust_result *result, stardust_db_commit_info *info);

96 B

uint32_t stardust_result_error(const stardust_result *result, stardust_diagnostic_view *output);

54 B

void stardust_result_release(stardust_result *result);

Parameters

stardust_db_mutation_run

Parameter	Type	Ownership	Default	Meaning
`mutation`	`stardust_db_mutation *`	Borrowed handle	Required	Keep the handle alive until the call returns.
`parameters`	`const stardust_document *`	Borrowed handle	NULL	An optional object of parameter values that merge-patches the definition's declared parameters. A parameter matched in the entity position of a fact clause takes an entity reference {#link id}, never the bare ID number: a commit returns IDs as numbers, so wrap one as {#link id}, or as the typed Link value where the binding has one, before passing it. A query run fails with `entity_reference_expected` when a bare number reaches that position. Projected and found entities also read back as {#link id}, so a typed field that receives one uses Link rather than a plain integer.
`options`	`const stardust_db_write_options *`	Borrowed input	NULL	The operation's options record. See its field defaults.
`explain`	`stardust_db_mutation_explain *`	Caller-owned output	NULL	Receives a record. Its pointer fields follow the record's ownership contract.
`output`	`stardust_result **`	Owned output	Required	Receives a library-owned handle. Release it after use.

stardust_db_result_commit_info

Parameter	Type	Ownership	Default	Meaning
`result`	`const stardust_result *`	Borrowed handle	Required	Keep the handle alive until the call returns.
`info`	`stardust_db_commit_info *`	Caller-owned output	Required	Receives a record. Its pointer fields follow the record's ownership contract.

stardust_result_error

Parameter	Type	Ownership	Default	Meaning
`result`	`const stardust_result *`	Borrowed handle	Required	Keep the handle alive until the call returns.
`output`	`stardust_diagnostic_view *`	Caller-owned output	Required	Receives a record. Its pointer fields follow the record's ownership contract.

stardust_result_release

Parameter	Type	Ownership	Default	Meaning
`result`	`stardust_result *`	Consumed handle	NULL	Ends ownership. Do not use the handle after this call.

Errors

Status	When
`STARDUST_INVALID_DEFINITION`	the mutation selection or definition is invalid
`STARDUST_INVALID_ARGUMENT`	the parameters or run options are invalid
`STARDUST_SCHEMA_VIOLATION`	the write breaks a schema
`STARDUST_CONFLICT`	concurrent writes prevent the commit
`STARDUST_REJECTED`	a mutation target or write guard refuses the write
`STARDUST_UNAVAILABLE`	the patch sets stardust/history and no enabled plugin purges history
`STARDUST_EVALUATION_FAILED`	the mutation fails
`STARDUST_CLOSED`	the parent database is closed
`STARDUST_OUT_OF_MEMORY`	native memory is exhausted

Notes

Mutation documents.

Examples

mutation/run

birthday_text holds this document:

json

186 B

{
  "query": {
    "find": [
      "?e"
    ],
    "where": [
      [
        "?e",
        "name",
        "Ada"
      ]
    ]
  },
  "patch": {
    "?e": {
      "age": 37
    }
  }
}

615 B

stardust_document *definition = NULL;
stardust_db_mutation *mutation = NULL;
stardust_result *result = NULL;
uint32_t status = stardust_parse(birthday_text, STARDUST_JSON, &definition);
stardust_db_source source = {.kind = STARDUST_SOURCE_DOCUMENT, .document = definition};
if (status == STARDUST_OK) status = stardust_db_mutation_open(db, &source, &mutation);
if (status == STARDUST_OK) status = stardust_db_mutation_run(mutation, NULL, NULL, NULL, &result);
stardust_db_mutation_release(mutation);
stardust_document_release(definition);
if (status != STARDUST_OK) {stardust_result_release(result); return status;}

Result / 111 B

{
  "status": "committed",
  "transaction": 5,
  "facts": 1,
  "committed_at": 17923367935512435,
  "ids": {}
}

Explain mutation execution

birthday_text holds this document:

json

186 B

{
  "query": {
    "find": [
      "?e"
    ],
    "where": [
      [
        "?e",
        "name",
        "Ada"
      ]
    ]
  },
  "patch": {
    "?e": {
      "age": 37
    }
  }
}

711 B

stardust_document *definition = NULL;
stardust_db_mutation *mutation = NULL;
stardust_result *written = NULL;
stardust_db_mutation_explain explain = {0};
uint32_t status = stardust_parse(birthday_text, STARDUST_JSON, &definition);
stardust_db_source source = {.kind = STARDUST_SOURCE_DOCUMENT, .document = definition};
if (status == STARDUST_OK) status = stardust_db_mutation_open(db, &source, &mutation);
if (status == STARDUST_OK) status = stardust_db_mutation_run(mutation, NULL, NULL, &explain, &written);
stardust_result_release(written);
stardust_db_mutation_release(mutation);
stardust_document_release(definition);
if (status != STARDUST_OK) return status;
stardust_db_mutation_explain result = explain;

Result / 389 B

{
  "load_definition": {
    "cpu": 1202,
    "wall": 1209,
    "arena_bytes": 2320
  },
  "parameters": {
    "cpu": 6,
    "wall": 8,
    "arena_bytes": 0
  },
  "run": {
    "cpu": 7245,
    "wall": 47836,
    "arena_bytes": 43856
  },
  "total": {
    "cpu": 8537,
    "wall": 49139,
    "arena_bytes": 46176
  },
  "arena_capacity": 4194304,
  "stages_completed": 3,
  "attempts": 1
}

Also calls: stardust_db_result_commit_info, stardust_result_error, stardust_result_release

stardust_db_mutation_release

66 B

void stardust_db_mutation_release(stardust_db_mutation *mutation);

Consumes the receiver handle.

Parameters

Parameter	Type	Ownership	Default	Meaning
`mutation`	`stardust_db_mutation *`	Consumed handle	NULL	Ends ownership. Do not use the handle after this call.

Examples

mutation/close

birthday_text holds this document:

json

186 B

{
  "query": {
    "find": [
      "?e"
    ],
    "where": [
      [
        "?e",
        "name",
        "Ada"
      ]
    ]
  },
  "patch": {
    "?e": {
      "age": 37
    }
  }
}

615 B

stardust_document *definition = NULL;
stardust_db_mutation *mutation = NULL;
stardust_result *result = NULL;
uint32_t status = stardust_parse(birthday_text, STARDUST_JSON, &definition);
stardust_db_source source = {.kind = STARDUST_SOURCE_DOCUMENT, .document = definition};
if (status == STARDUST_OK) status = stardust_db_mutation_open(db, &source, &mutation);
if (status == STARDUST_OK) status = stardust_db_mutation_run(mutation, NULL, NULL, NULL, &result);
stardust_db_mutation_release(mutation);
stardust_document_release(definition);
if (status != STARDUST_OK) {stardust_result_release(result); return status;}

Result / 111 B

{
  "status": "committed",
  "transaction": 5,
  "facts": 1,
  "committed_at": 17923367934714808,
  "ids": {}
}

stardust_db_merge_patch

186 B

uint32_t stardust_db_merge_patch(stardust_db *db, const stardust_document *patch, const stardust_db_write_options *options, stardust_db_patch_explain *explain, stardust_result **output);

102 B

uint32_t stardust_db_result_commit_info(const stardust_result *result, stardust_db_commit_info *info);

96 B

uint32_t stardust_result_error(const stardust_result *result, stardust_diagnostic_view *output);

54 B

void stardust_result_release(stardust_result *result);

Parameters

stardust_db_merge_patch

Parameter	Type	Ownership	Default	Meaning
`db`	`stardust_db *`	Borrowed handle	Required	Keep the handle alive until the call returns.
`patch`	`const stardust_document *`	Borrowed handle	Required	An entity-keyed native patch. Temporary names use `#_name`. `#_tx` holds metadata and an optional stardust/checkAndSet map from entity IDs to expected transactions. Positive expectations match exact last-touch transactions; zero requires no current facts. Conditions are consumed and checked atomically, including for no-ops.
`options`	`const stardust_db_write_options *`	Borrowed input	NULL	Caller-owned record read during the call.
`explain`	`stardust_db_patch_explain *`	Caller-owned output	NULL	Receives a record. Its pointer fields follow the record's ownership contract.
`output`	`stardust_result **`	Owned output	Required	Receives a library-owned handle. Release it after use.

stardust_db_result_commit_info

Parameter	Type	Ownership	Default	Meaning
`result`	`const stardust_result *`	Borrowed handle	Required	Keep the handle alive until the call returns.
`info`	`stardust_db_commit_info *`	Caller-owned output	Required	Receives a record. Its pointer fields follow the record's ownership contract.

stardust_result_error

Parameter	Type	Ownership	Default	Meaning
`result`	`const stardust_result *`	Borrowed handle	Required	Keep the handle alive until the call returns.
`output`	`stardust_diagnostic_view *`	Caller-owned output	Required	Receives a record. Its pointer fields follow the record's ownership contract.

stardust_result_release

Parameter	Type	Ownership	Default	Meaning
`result`	`stardust_result *`	Consumed handle	NULL	Ends ownership. Do not use the handle after this call.

Errors

Status	When
`STARDUST_INVALID_COMMIT_TIME`	the `#_tx` commit time is not later than the last commit
`STARDUST_CONFLICT`	an entity revision check fails or a concurrent writer prevents the commit; a revision mismatch reports the entity and expected and actual revisions
`STARDUST_REJECTED`	the database refuses the patch; the code and diagnostic path name the reason and key
`STARDUST_UNAVAILABLE`	the patch sets stardust/history and no enabled plugin purges history
`STARDUST_INVALID_ARGUMENT`	the patch is not an entity-keyed object, or a link names an ID outside the user entity range
`STARDUST_CLOSED`	the database is closed
`STARDUST_OUT_OF_MEMORY`	native memory is exhausted

Notes

Patch documents.

Examples

database/merge_patch

seed_text holds this document:

json

333 B

{
  "#_ada": {
    "name": "Ada",
    "role": "engineer",
    "age": 36
  },
  "#_bob": {
    "name": "Bob",
    "role": "engineer",
    "age": 41,
    "mentor": {
      "#link": "#_ada"
    }
  },
  "#_cy": {
    "name": "Cy",
    "role": "designer",
    "age": 29
  },
  "#_tx": {
    "author": "smoke",
    "reason": "seed"
  }
}

336 B

stardust_document *patch = NULL;
stardust_result *result = NULL;
uint32_t status = stardust_parse(seed_text, STARDUST_JSON, &patch);
if (status == STARDUST_OK) status = stardust_db_merge_patch(db, patch, NULL, NULL, &result);
stardust_document_release(patch);
if (status != STARDUST_OK) {stardust_result_release(result); return status;}

Result / 161 B

{
  "status": "committed",
  "transaction": 4,
  "facts": 12,
  "committed_at": 17923367928294190,
  "ids": {
    "#_ada": 1,
    "#_bob": 2,
    "#_cy": 3
  }
}

Explain patch validation and commit

seed_text holds this document:

json

333 B

{
  "#_ada": {
    "name": "Ada",
    "role": "engineer",
    "age": 36
  },
  "#_bob": {
    "name": "Bob",
    "role": "engineer",
    "age": 41,
    "mentor": {
      "#link": "#_ada"
    }
  },
  "#_cy": {
    "name": "Cy",
    "role": "designer",
    "age": 29
  },
  "#_tx": {
    "author": "smoke",
    "reason": "seed"
  }
}

426 B

stardust_document *patch = NULL;
stardust_db_patch_explain explain = {0};
stardust_result *written = NULL;
uint32_t status = stardust_parse(seed_text, STARDUST_JSON, &patch);
if (status == STARDUST_OK) status = stardust_db_merge_patch(db, patch, NULL, &explain, &written);
stardust_result_release(written);
stardust_document_release(patch);
if (status != STARDUST_OK) return status;
stardust_db_patch_explain result = explain;

Result / 298 B

{
  "copy_patch": {
    "cpu": 11049,
    "wall": 11091,
    "arena_bytes": 3096
  },
  "commit": {
    "cpu": 315,
    "wall": 31173,
    "arena_bytes": 8008
  },
  "total": {
    "cpu": 11512,
    "wall": 42419,
    "arena_bytes": 11118
  },
  "arena_capacity": 4194304,
  "stages_completed": 2
}

Refuse a metadata-only transaction

patch_text holds this document:

json

38 B

{
  "#_tx": {
    "author": "x"
  }
}

390 B

stardust_document *patch = NULL;
stardust_result *failed = NULL;
uint32_t status = stardust_parse(patch_text, STARDUST_JSON, &patch);
if (status != STARDUST_OK) {stardust_document_release(patch); return status;}
status = stardust_db_merge_patch(db, patch, NULL, NULL, &failed);
stardust_document_release(patch);
stardust_diagnostic_view result = {0};
stardust_result_error(failed, &result);

Result / 199 B

{
  "code": "transaction_only",
  "message": "a patch of only #_tx is refused: #_tx annotates a write",
  "path": "#_tx",
  "field": null,
  "entity": null,
  "offset": null,
  "status": "rejected"
}

Refuse a repeated commit time

future_text holds this document:

json

120 B

{
  "#_d": {
    "x": 1
  },
  "#_tx": {
    "stardust/committedAt": {
      "#utc": "2200-01-01T00:00:00Z"
    }
  }
}

patch_text holds this document:

json

120 B

{
  "#_e": {
    "x": 2
  },
  "#_tx": {
    "stardust/committedAt": {
      "#utc": "2200-01-01T00:00:00Z"
    }
  }
}

716 B

stardust_document *future = NULL;
stardust_document *patch = NULL;
stardust_result *committed = NULL;
uint32_t status = stardust_parse(future_text, STARDUST_JSON, &future);
if (status == STARDUST_OK) status = stardust_parse(patch_text, STARDUST_JSON, &patch);
if (status == STARDUST_OK) status = stardust_db_merge_patch(db, future, NULL, NULL, &committed);
stardust_result_release(committed);
stardust_document_release(future);
if (status != STARDUST_OK) {stardust_document_release(patch); return status;}
stardust_result *failed = NULL;
status = stardust_db_merge_patch(db, patch, NULL, NULL, &failed);
stardust_document_release(patch);
stardust_diagnostic_view result = {0};
stardust_result_error(failed, &result);

Result / 227 B

{
  "code": "invalid_commit_time",
  "message": "stardust/committedAt must be strictly newer than the latest commit time",
  "path": null,
  "field": null,
  "entity": null,
  "offset": null,
  "status": "invalid_commit_time"
}

Also calls: stardust_db_result_commit_info, stardust_result_error, stardust_result_release

stardust_db_indexes_sync

75 B

uint32_t stardust_db_indexes_sync(stardust_db *db, int64_t max_wait_ticks);

Parameters

Parameter	Type	Ownership	Default	Meaning
`db`	`stardust_db *`	Borrowed handle	Required	Keep the handle alive until the call returns.
`max_wait_ticks`	`int64_t`	Value	Required	Value passed to the call.

Errors

Status	When
`STARDUST_INVALID_ARGUMENT`	`max_wait` is negative
`STARDUST_TIMEOUT`	`max_wait` passed first
`STARDUST_CLOSED`	the database is closed

Notes

An index that cannot be built does not hold this wait.

Examples

Wait for the exact indexes of the stored queries

542 B

stardust_result *listed = NULL;
stardust_bytes kind = {(const uint8_t *)"queries", 7};
stardust_bytes pattern = {(const uint8_t *)"people/.*", 9};
uint32_t status = stardust_db_indexes_sync(db, 50000000);
if (status == STARDUST_OK) status = stardust_db_definition_list(db, kind, pattern, &listed);
if (status != STARDUST_OK) { stardust_result_release(listed); return status; }
stardust_document *result = NULL;
status = stardust_result_take_document(listed, &result);
stardust_result_release(listed);
if (status != STARDUST_OK) return status;

Result / 22 B

[
  "people/by_role"
]

stardust_db_bulk_begin

49 B

uint32_t stardust_db_bulk_begin(stardust_db *db);

Parameters

Parameter	Type	Ownership	Default	Meaning
`db`	`stardust_db *`	Borrowed handle	Required	Keep the handle alive until the call returns.

Errors

Status	When
`STARDUST_INVALID_ARGUMENT`	a bulk build is already in progress on the database
`STARDUST_CLOSED`	the database is closed
`STARDUST_OUT_OF_MEMORY`	native memory is exhausted

Notes

On a database with existing facts, each added patch commits immediately and the summary reports fallback true. Closing the database drops an unfinished build.

Examples

Start a bulk build and drop it

282 B

uint32_t status = stardust_db_bulk_begin(db);
if (status != STARDUST_OK) return status;
// A second build on the same database is refused while this one runs.
if (stardust_db_bulk_begin(db) != STARDUST_INVALID_ARGUMENT) return STARDUST_EVALUATION_FAILED;
stardust_db_bulk_abort(db);

stardust_db_bulk_add

79 B

uint32_t stardust_db_bulk_add(stardust_db *db, const stardust_document *patch);

Parameters

Parameter	Type	Ownership	Default	Meaning
`db`	`stardust_db *`	Borrowed handle	Required	Keep the handle alive until the call returns.
`patch`	`const stardust_document *`	Borrowed handle	Required	One borrowed entity-keyed merge-patch document, as `merge_patch` takes it. Temporary names use `#_name` and are scoped to this patch. Transaction metadata uses `#_tx`. The document is borrowed only until the call returns.

Errors

Status	When
`STARDUST_INVALID_ARGUMENT`	no bulk build is in progress
`STARDUST_REJECTED`	the database refuses the patch; the build has failed and later adds report the same status
`STARDUST_CLOSED`	the database is closed
`STARDUST_OUT_OF_MEMORY`	native memory is exhausted

Notes

Patches retain add order. Entity and field order within a patch does not matter. Temporary names resolve within one patch. The call waits for space within the build's memory budget. After failure, use finish for its diagnostic or abort for cleanup.

Patch documents.

Examples

Queue patches in commit order

826 B

// The first entity of an empty database is 1, so the second patch updates it.
const char *patches[] = {"{\"#_ada\":{\"name\":\"Ada\"}}", "{\"1\":{\"title\":\"Countess\"}}"};
stardust_result *finished = NULL;
uint32_t status = stardust_db_bulk_begin(db);
for (size_t index = 0; status == STARDUST_OK && index < 2; index++) {
    stardust_bytes patch = {(const uint8_t *)patches[index], (int64_t)strlen(patches[index])};
    stardust_document *document = NULL;
    status = stardust_parse(patch, STARDUST_JSON, &document);
    if (status == STARDUST_OK) status = stardust_db_bulk_add(db, document);
    stardust_document_release(document);
}
if (status == STARDUST_OK) status = stardust_db_bulk_finish(db, &finished);
else stardust_db_bulk_abort(db);
stardust_result_release(finished);
if (status != STARDUST_OK) return status;

stardust_db_bulk_finish

76 B

uint32_t stardust_db_bulk_finish(stardust_db *db, stardust_result **output);

92 B

uint32_t stardust_result_take_document(stardust_result *result, stardust_document **output);

96 B

uint32_t stardust_result_error(const stardust_result *result, stardust_diagnostic_view *output);

54 B

void stardust_result_release(stardust_result *result);

Parameters

stardust_db_bulk_finish

Parameter	Type	Ownership	Default	Meaning
`db`	`stardust_db *`	Borrowed handle	Required	Keep the handle alive until the call returns.
`output`	`stardust_result **`	Owned output	Required	Receives a library-owned handle. Release it after use.

stardust_result_take_document

Parameter	Type	Ownership	Default	Meaning
`result`	`stardust_result *`	Borrowed handle	Required	Keep the handle alive until the call returns.
`output`	`stardust_document **`	Owned output	Required	Receives a library-owned handle. Release it after use.

stardust_result_error

Parameter	Type	Ownership	Default	Meaning
`result`	`const stardust_result *`	Borrowed handle	Required	Keep the handle alive until the call returns.
`output`	`stardust_diagnostic_view *`	Caller-owned output	Required	Receives a record. Its pointer fields follow the record's ownership contract.

stardust_result_release

Parameter	Type	Ownership	Default	Meaning
`result`	`stardust_result *`	Consumed handle	NULL	Ends ownership. Do not use the handle after this call.

Errors

Status	When
`STARDUST_INVALID_ARGUMENT`	no bulk build is in progress
`STARDUST_REJECTED`	the database refuses a patch; an initial build publishes nothing and fallback keeps earlier commits
`STARDUST_CONFLICT`	another write committed to the database during the build
`STARDUST_CLOSED`	the database is closed
`STARDUST_OUT_OF_MEMORY`	native memory is exhausted

Notes

Finish ends the build even on failure. An initial build publishes all patches or none. Fallback keeps patches already committed.

The summary contains:

Field	Meaning
status	committed, or `no_change` when nothing was written
patches, transactions, facts, entities	Load counts
firstTransaction, lastTransaction	Assigned transaction range
fallback	Whether patches committed individually
threads	Worker count
tempBytes	Temporary run bytes
memoryBytes, memoryPeakBytes	Reserved memory share and its peak use
phases	parse, assign, rows, updates, spill, build and commit timings, each with wallNs and cpuNs

The memory budget covers build allocations. It excludes operating-system file cache and the process baseline.

Examples

Load patches with one commit and read the summary

928 B

const char *text = "{\"#_ada\":{\"name\":\"Ada\",\"title\":\"Countess\"}}";
stardust_bytes patch = {(const uint8_t *)text, (int64_t)strlen(text)};
stardust_result *finished = NULL;
stardust_document *summary = NULL;
uint32_t status = stardust_db_bulk_begin(db);
stardust_document *document = NULL;
if (status == STARDUST_OK) status = stardust_parse(patch, STARDUST_JSON, &document);
if (status == STARDUST_OK) status = stardust_db_bulk_add(db, document);
stardust_document_release(document);
// finish ends the build also when it fails.
if (status == STARDUST_OK) status = stardust_db_bulk_finish(db, &finished);
else stardust_db_bulk_abort(db);
if (status == STARDUST_OK) status = stardust_result_take_document(finished, &summary);
stardust_result_release(finished);
// summary holds status, patches, transactions, facts, entities and phase timings.
stardust_document_release(summary);
if (status != STARDUST_OK) return status;

Also calls: stardust_result_take_document, stardust_result_error, stardust_result_release

stardust_db_bulk_abort

45 B

void stardust_db_bulk_abort(stardust_db *db);

Parameters

Parameter	Type	Ownership	Default	Meaning
`db`	`stardust_db *`	Borrowed handle	NULL	Keep the handle alive until the call returns.

Notes

Abort preserves patches already committed in fallback mode. It is safe without a build or after database closure.

Examples

Drop a bulk build without writing it

527 B

const char *text = "{\"#_ada\":{\"name\":\"Ada\"}}";
stardust_bytes patch = {(const uint8_t *)text, (int64_t)strlen(text)};
uint32_t status = stardust_db_bulk_begin(db);
stardust_document *document = NULL;
if (status == STARDUST_OK) status = stardust_parse(patch, STARDUST_JSON, &document);
if (status == STARDUST_OK) status = stardust_db_bulk_add(db, document);
stardust_document_release(document);
// Abort writes nothing; without a build it does nothing.
stardust_db_bulk_abort(db);
if (status != STARDUST_OK) return status;

stardust_db_subscription_set_notify

59 B

typedef void (*stardust_db_subscription_notify)(void *ctx);

127 B

uint32_t stardust_db_subscription_set_notify(stardust_db_subscription *sub, stardust_db_subscription_notify notify, void *ctx);

Parameters

Parameter	Requirement	Meaning
`sub`	Required	Subscription receiving the callback. Use the handle exclusively during registration.
`notify`	Required	Readiness callback.
`ctx`	NULL is valid	Caller-owned state, passed unchanged to the callback. Stardust does not read or free it.

Notes

Use this optional callback to wake a host scheduler without polling or a dedicated waiting thread. Blocking next works without registration.

Register a borrowed signal-only C callback once, before any next call. NULL context is valid. Native registration allocates nothing. Install the application waiter before next with zero wait; TIMEOUT arms a coalesced readiness hint. The callback may run on any thread, must return promptly, and must not call Stardust or run application work. Keep callback code and context valid until subscription release returns; no callback is running or can run afterward. Concurrent next calls race for events. A null subscription or callback, duplicate registration, or registration after next reports invalid_argument. A failed subscription preserves its saved failure. A rejected registration retains nothing.

The example requires a C implementation with C11 threads (<threads.h>) and timed condition waits.

Examples

Wait through a readiness callback

query_text holds this document:

json

134 B

{
  "find": [
    "?name"
  ],
  "where": [
    [
      "?e",
      "name",
      "?name"
    ]
  ],
  "orderBy": [
    "?name"
  ]
}

2.6 kB

#include <threads.h>
#include <time.h>
#include <stdlib.h>

struct subscription_waiter {
    mtx_t mutex;
    cnd_t changed;
    uint64_t generation;
};

static void notify_sync_check(int status) {
    if (status != thrd_success) abort();
}

static void subscription_ready(void *ctx) {
    struct subscription_waiter *waiter = ctx;
    notify_sync_check(mtx_lock(&waiter->mutex));
    waiter->generation++;
    notify_sync_check(cnd_broadcast(&waiter->changed));
    notify_sync_check(mtx_unlock(&waiter->mutex));
}

struct subscription_waiter waiter = {0};
if (mtx_init(&waiter.mutex, mtx_plain) != thrd_success) return STARDUST_OUT_OF_MEMORY;
if (cnd_init(&waiter.changed) != thrd_success) {
    mtx_destroy(&waiter.mutex);
    return STARDUST_OUT_OF_MEMORY;
}
stardust_document *definition = NULL;
stardust_db_query *query = NULL;
stardust_db_subscription *subscription = NULL;
stardust_db_live_event event = {0};
uint32_t status = stardust_parse(query_text, STARDUST_JSON, &definition);
stardust_db_source source = {.kind = STARDUST_SOURCE_DOCUMENT, .document = definition};
if (status == STARDUST_OK) status = stardust_db_query_open(db, &source, &query);
if (status == STARDUST_OK) status = stardust_db_query_subscribe(query, NULL, NULL, &subscription);
if (status == STARDUST_OK) status = stardust_db_subscription_set_notify(subscription, subscription_ready, &waiter);
struct timespec deadline = {0};
if (timespec_get(&deadline, TIME_UTC) != TIME_UTC) status = STARDUST_INVALID_ARGUMENT;
deadline.tv_sec += 5;
while (status == STARDUST_OK) {
    notify_sync_check(mtx_lock(&waiter.mutex));
    uint64_t observed = waiter.generation;
    notify_sync_check(mtx_unlock(&waiter.mutex));
    status = stardust_db_subscription_next(subscription, 0, &event);
    if (status != STARDUST_TIMEOUT) break;
    notify_sync_check(mtx_lock(&waiter.mutex));
    int waited = thrd_success;
    while (waiter.generation == observed && waited == thrd_success)
        waited = cnd_timedwait(&waiter.changed, &waiter.mutex, &deadline);
    notify_sync_check(mtx_unlock(&waiter.mutex));
    if (waited == thrd_success) status = STARDUST_OK;
    else if (waited != thrd_timedout) status = STARDUST_INVALID_ARGUMENT;
}
// Release joins callbacks before the stack context or its mutex is destroyed.
stardust_db_subscription_release(subscription);
stardust_db_query_release(query);
stardust_document_release(definition);
cnd_destroy(&waiter.changed);
mtx_destroy(&waiter.mutex);
if (status != STARDUST_OK) {stardust_document_release(event.result); return status;}
stardust_document *result = event.result;

Result / 82 B

[
  {
    "name": "Ada"
  },
  {
    "name": "Bob"
  },
  {
    "name": "Cy"
  }
]

stardust_db_query_options

This record supplies options for query and mutation run. Zero selects each default. Mutations use DB_Write_Options, whose fields are a subset.

Note

Supply size and version with each record. NULL options select the defaults of the call.

Field	C type	Unit	Range	Default	Meaning
`size`	`uint32_t`	Bytes	Unsigned u32	Required: sizeof(stardust_db_query_options)	—
`version`	`uint32_t`	None	Unsigned u32	Required: 1	—
`page_size`	`uint32_t`	Count	Unsigned u32	0 selects the default page size	Rows per page. 0 selects the default page size. Queries only.
`reserved`	`uint32_t`	None	Unsigned u32	0	Must be zero.
`max_cost_ticks`	`int64_t`	100 ns ticks	Signed i64	0 selects the dynamic CPU budget	Thread CPU duration limit. 0 selects the engine’s dynamic budget.
`as_of`	`int64_t`	None	Signed i64	Zero	A positive transaction runs a stored definition as of that transaction.

stardust_db_write_options

Note

Supply size and version with each record. NULL options select the defaults of the call.

Field	C type	Unit	Range	Default	Meaning
`size`	`uint32_t`	Bytes	Unsigned u32	Required: sizeof(stardust_db_write_options)	—
`version`	`uint32_t`	None	Unsigned u32	Required: 1	—
`max_cost_ticks`	`int64_t`	100 ns ticks	Signed i64	0 selects the dynamic CPU budget	Thread CPU duration limit. 0 selects the engine’s dynamic budget.
`as_of`	`int64_t`	None	Signed i64	Zero	A positive transaction runs a stored definition as of that transaction.

stardust_db_commit_info

This record contains the result of mutation run, merge_patch and patch_definition.

Field	C type	Unit	Range	Default	Meaning
`status`	`uint32_t`	None	Unsigned u32	The call sets it	—
`reserved`	`uint32_t`	None	Unsigned u32	0	Must be zero.
`transaction`	`int64_t`	None	Signed i64	The call sets it	Zero when nothing was written.
`facts`	`int64_t`	Count	Signed i64	The call sets it	—
`committed_at_ticks`	`int64_t`	100 ns ticks since the Unix epoch (UTC)	Signed i64	The call sets it	Recorded commit time as a UTC instant. The call measures this value. Independent calls can differ.

stardust_db_live_event

This record contains the result of subscription next.

Field	C type	Unit	Range	Meaning
`sequence`	`int64_t`	Count	Signed i64	Event number. Event 1 is the initial result.
`superseded`	`int64_t`	Count	Signed i64	Intermediate computed results skipped by this subscription since its previous event. Zero for its first event. The delivered result replaces them in full. This value counts neither commits nor changed rows.
`transaction`	`int64_t`	None	Signed i64	Transaction the result was computed at.
`result`	`stardust_document *`	None	C type range	The full query result. The event owns it and the consumer closes it.