Francis Chuang created CALCITE-1196:
---------------------------------------
Summary: Cache statement handle signatures for prepared statements
so that the client won't have to send them during execution
Key: CALCITE-1196
URL: https://issues.apache.org/jira/browse/CALCITE-1196
Project: Calcite
Issue Type: Improvement
Components: avatica
Affects Versions: avatica-1.7.1
Reporter: Francis Chuang
Priority: Minor
With avatica 1.7.1, to prepare and execute a statement, we need to do the
following (shown using curl):
{code}
C:\Users\user
λ curl localhost:8765 -XPOST --data '{"request": "prepare","connectionId":
"my-conn","sql": "SELECT * FROM my_table","maxRowCount": 1}'
{
"response": "prepare",
"statement": {
"connectionId": "my-conn",
"id": 25,
"signature": {
"columns": [
{
"ordinal": 0,
"autoIncrement": false,
"caseSensitive": false,
"searchable": true,
"currency": false,
"nullable": 0,
"signed": true,
"displaySize": 40,
"label": "K",
"columnName": "K",
"schemaName": "",
"precision": 0,
"scale": 0,
"tableName": "MY_TABLE",
"catalogName": "",
"type": {
"type": "scalar",
"id": -5,
"name": "BIGINT",
"rep": "PRIMITIVE_LONG"
},
"readOnly": true,
"writable": false,
"definitelyWritable": false,
"columnClassName": "java.lang.Long"
},
{
"ordinal": 1,
"autoIncrement": false,
"caseSensitive": false,
"searchable": true,
"currency": false,
"nullable": 1,
"signed": false,
"displaySize": 40,
"label": "V",
"columnName": "V",
"schemaName": "",
"precision": 0,
"scale": 0,
"tableName": "MY_TABLE",
"catalogName": "",
"type": {
"type": "scalar",
"id": 12,
"name": "VARCHAR",
"rep": "STRING"
},
"readOnly": true,
"writable": false,
"definitelyWritable": false,
"columnClassName": "java.lang.String"
}
],
"sql": "SELECT * FROM my_table",
"parameters": [],
"cursorFactory": {
"style": "LIST",
"clazz": null,
"fieldNames": null
},
"statementType": null
}
},
"rpcMetadata": {
"response": "rpcMetadata",
"serverAddress": "f826338-phoenix-server.f826338:8765"
}
}
C:\Users\user
λ curl localhost:8765 -XPOST --data '{
"request": "execute",
"statementHandle": {
"connectionId": "my-conn",
"id": 25,
"signature": {
"columns": [
{
"ordinal": 0,
"autoIncrement": false,
"caseSensitive": false,
"searchable": true,
"currency": false,
"nullable": 0,
"signed": true,
"displaySize": 40,
"label": "K",
"columnName": "K",
"schemaName": "",
"precision": 0,
"scale": 0,
"tableName": "MY_TABLE",
"catalogName": "",
"type": {
"type": "scalar",
"id": -5,
"name": "BIGINT",
"rep": "PRIMITIVE_LONG"
},
"readOnly": true,
"writable": false,
"definitelyWritable": false,
"columnClassName": "java.lang.Long"
},
{
"ordinal": 1,
"autoIncrement": false,
"caseSensitive": false,
"searchable": true,
"currency": false,
"nullable": 1,
"signed": false,
"displaySize": 40,
"label": "V",
"columnName": "V",
"schemaName": "",
"precision": 0,
"scale": 0,
"tableName": "MY_TABLE",
"catalogName": "",
"type": {
"type": "scalar",
"id": 12,
"name": "VARCHAR",
"rep": "STRING"
},
"readOnly": true,
"writable": false,
"definitelyWritable": false,
"columnClassName": "java.lang.String"
}
],
"sql": "SELECT * FROM my_table",
"parameters": [],
"cursorFactory": {
"style": "LIST",
"clazz": null,
"fieldNames": null
},
"statementType": null
}
},
"parameterValues": [],
"maxRowCount": 1
}'
{code}
Notice that we receive the signature in the {{statementHandle}} when running a
prepare request. We then attach this so the execute request to execute the
statement.
The UX can be improved by caching that signature on the server along with the
prepared statement to avoid having to ask the client to send it with the
execution request.
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