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https://issues.apache.org/jira/browse/CALCITE-1196?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15238538#comment-15238538
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Josh Elser commented on CALCITE-1196:
-------------------------------------
[~julianhyde], I was wonder if you recall a reason that the Signature isn't
cached with a StatementInfo inside the server. It seems like we could avoid
sending it back over the wire in Execute.
If not, no a big deal. I can mess around with it.
> 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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