DQL Learning
- Dgraph Zero controls the Dgraph cluster, and stores information about it. It automatically moves data between different Dgraph Alpha instances based on the size of the data served by each Alpha instance. Before you can run dgraph alpha, you must run at least one dgraph zero node
-
Dgraph Alpha provides several HTTP endpoints for administrators, as follows:
/health?all-
/admin/shutdowninitiates a proper shutdown of the Alpha.
Run dgraph zero and alpha separately
# Run Dgraph zero
docker run -it -p 5080:5080 -p 6080:6080 -p 8080:8080 \
-p 9080:9080 -p 8000:8000 -v ~/dgraph:/dgraph --name dgraph \
dgraph/dgraph:v21.03.0 dgraph zero
# In another terminal, now run Dgraph alpha
docker exec -it dgraph dgraph alpha --cache size-mb=2048 --zero localhost:5080 --security whitelist=0.0.0.0/0
or Standalone
docker run -it -p 5080:5080 -p 6080:6080 -p 8080:8080 \
-p 9080:9080 -p 8000:8000 -v ~/dgraph:/dgraph --name dgraph \
dgraph/standalone:v21.03.0
GET http://localhost:8080/admin/shutdown
A. To drop all data and schema:
$ curl -X POST localhost:8080/alter -d '{"drop_all": true}'
B. To drop all data only (keep schema):
$ curl -X POST localhost:8080/alter -d '{"drop_op": "DATA"}'
curl -X POST localhost:8080/admin/schema --data @schema.graphql
$ dgraph live -f 1million.rdf.gz --alpha localhost:9080 --zero localhost:5080 -c 1
or
$ docker exec -it dgraph dgraph live -f 1million.rdf.gz --alpha localhost:9080 --zero localhost:5080 -c 1
dgraph live --help
Run Dgraph Live Loader
Usage:
dgraph live [flags]
Flags:
-a, --alpha string Comma-separated list of Dgraph alpha gRPC server addresses (default "127.0.0.1:9080")
-t, --auth_token string The auth token passed to the server for Alter operation of the schema file. If used with --slash_grpc_endpoint, then this should be set to the API token issuedby Slash GraphQL
-b, --batch int Number of N-Quads to send as part of a mutation. (default 1000)
-m, --bufferSize string Buffer for each thread (default "100")
-c, --conc int Number of concurrent requests to make to Dgraph (default 10)
--creds string Various login credentials if login is required.
user defines the username to login.
password defines the password of the user.
namespace defines the namespace to log into.
Sample flag could look like --creds user=username;password=mypass;namespace=2
--encryption string [Enterprise Feature] Encryption At Rest options
key-file=; The file that stores the symmetric key of length 16, 24, or 32 bytes.The key size determines the chosen AES cipher (AES-128, AES-192, and AES-256 respectively).
(default "key-file=")
-f, --files string Location of *.rdf(.gz) or *.json(.gz) file(s) to load
--force-namespace int Namespace onto which to load the data.Only guardian of galaxy should use this for loading data into multiple namespaces or somespecific namespace. Setting it to negative value will preserve the namespace.
--format string Specify file format (rdf or json) instead of getting it from filename
-h, --help help for live
--http string Address to serve http (pprof). (default "localhost:6060")
--new_uids Ignore UIDs in load files and assign new ones.
-s, --schema string Location of schema file
--slash_grpc_endpoint string Path to Slash GraphQL GRPC endpoint. If --slash_grpc_endpoint is set, all other TLS options and connection options will beignored
--tls string TLS Client options
ca-cert=; The CA cert file used to verify server certificates. Required for enabling TLS.
client-cert=; (Optional) The Cert file provided by the client to the server.
client-key=; (Optional) The private Key file provided by the clients to the server.
internal-port=false; (Optional) Enable inter-node TLS encryption between cluster nodes.
server-name=; Used to verify the server hostname.
use-system-ca=true; Includes System CA into CA Certs.
(default "use-system-ca=true; internal-port=false;")
--tmp string Directory to store temporary buffers. (default "t")
-U, --upsertPredicate string run in upsertPredicate mode. the value would be used to store blank nodes as an xid
-C, --use_compression Enable compression on connection to alpha server
--vault string Vault options
addr=http://localhost:8200; Vault server address (format: http://ip:port).
enc-field=; Vault field containing encryption key.
enc-format=base64; Encryption key format, can be 'raw' or 'base64'.
path=secret/data/dgraph; Vault KV store path (e.g. 'secret/data/dgraph' for KV V2, 'kv/dgraph' for KV V1).
role-id-file=; Vault RoleID file, used for AppRole authentication.
secret-id-file=; Vault SecretID file, used for AppRole authentication.
(default "addr=http://localhost:8200; role-id-file=; secret-id-file=; path=secret/data/dgraph; enc-field=; enc-format=base64")
--verbose Run the live loader in verbose mode
-x, --xidmap string Directory to store xid to uid mapping
-z, --zero string Dgraph zero gRPC server address (default "127.0.0.1:5080")
Global Flags:
--alsologtostderr log to standard error as well as files
--bindall Use 0.0.0.0 instead of localhost to bind to all addresses on local machine. (default true)
--block_rate int Block profiling rate. Must be used along with block profile_mode
--config string Configuration file. Takes precedence over default values, but is overridden to values set with environment variables and flags.
--cwd string Change working directory to the path specified. The parent must exist.
--expose_trace Allow trace endpoint to be accessible from remote
--log_backtrace_at traceLocation when logging hits line file:N, emit a stack trace (default :0)
--log_dir string If non-empty, write log files in this directory
--logtostderr log to standard error instead of files
--profile_mode string Enable profiling mode, one of [cpu, mem, mutex, block]
-v, --v Level log level for V logs
--vmodule moduleSpec comma-separated list of pattern=N settings for file-filtered logging
{
q(func: allofterms(name@., "Michael")) {
name
age
friend(orderasc: age, offset: 1, first: 2) @filter(ge(age, 27) AND le(age, 48)) {
name@.
age
}
count(friend) @filter(between(age, 27, 48))
}
}
{
lots_of_friends(func: ge(count(friend), 2)) {
name@.
age
friend {
name@.
}
}
}
- returns only edges listed with an alias, and
- flattens the result to remove nesting
{
michael_and_pet_name(func: allofterms(name@., "Michael")) @normalize {
name: name
age # this wont come out because there is no alias
friend {
friend_name: name
}
}
}
$ curl -sH "Content-Type: application/rdf" "localhost:8080/mutate?commitNow=true" -XPOST -d $'
{
set {
# -- Facets on scalar predicates
_:alice <name> "Alice" .
_:alice <mobile> "040123456" (since=2006-01-02T15:04:05) .
_:alice <car> "MA0123" (since=2006-02-02T13:01:09, first=true) .
}
} | python -m json.tool
{
"set": [
{
"uid": "_:company1",
"industry": "Machinery",
"dgraph.type": "Company",
"name": "CompanyABC"
}
]
}