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(core) fix filters with many values when querying directly from db

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Summary:
This fixes DocStorage.fetchQuery when the number of parameters
exceeds the maximum that can be passed directly to sqlite.
In this case, parameters are now stored and used from a temporary
table.

Problem first noticed via a use of DocStorage.fetchQuery by
granular access controls.  Access control should be optimized
to make fewer such queries, but that is a separate issue.

Test Plan: added tests

Reviewers: dsagal

Reviewed By: dsagal

Differential Revision: https://phab.getgrist.com/D2772
This commit is contained in:
Paul Fitzpatrick 2021-04-14 11:00:25 -04:00
parent 45141ed438
commit 9e8e895abd
1 changed files with 55 additions and 6 deletions
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61
app/server/lib/DocStorage.ts
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@ -796,6 +796,14 @@ export class DocStorage implements ISQLiteDB {
* are not easily stored as sqlite's native types.
*/
public async fetchQuery(query: ExpandedQuery): Promise<Buffer> {
// Check if there are a lot of parameters, and if so, switch to a method that can support
// that.
const totalParameters = Object.values(query.filters).map(vs => vs.length).reduce((a, b) => a + b, 0);
if (totalParameters > maxSQLiteVariables) {
// Fall back on using temporary tables if there are many parameters.
return this._fetchQueryWithManyParameters(query);
}
// Convert query to SQL.
const params: any[] = [];
const whereParts: string[] = [];
@ -805,12 +813,7 @@ export class DocStorage implements ISQLiteDB {
whereParts.push(`${quoteIdent(query.tableId)}.${quoteIdent(colId)} IN (${values.map(() => '?').join(', ')})`);
params.push(...values);
}
const whereClause = whereParts.length > 0 ? `WHERE ${whereParts.join(' AND ')}` : '';
const limitClause = (typeof query.limit === 'number') ? `LIMIT ${query.limit}` : '';
const joinClauses = query.joins ? query.joins.join(' ') : '';
const selects = query.selects ? query.selects.join(', ') : '*';
const sql = `SELECT ${selects} FROM ${quoteIdent(query.tableId)} ` +
`${joinClauses} ${whereClause} ${limitClause}`;
const sql = this._getSqlForQuery(query, whereParts);
return this._getDB().allMarshal(sql, params);
}
@ -1450,6 +1453,52 @@ export class DocStorage implements ISQLiteDB {
"AND tbl_name NOT LIKE '_grist%' " +
"ORDER BY tableId, colId") as any;
}
/**
* Implement a filtered query by adding any parameters into
* temporary tables, to avoid hitting an SQLite parameter limit.
* Backing for temporary tables lies outside of the document database,
* and operates with `synchronous=OFF` and `journal_mode=PERSIST`, so
* should be reasonably fast:
* https://sqlite.org/tempfiles.html#temp_databases
*/
public async _fetchQueryWithManyParameters(query: ExpandedQuery): Promise<Buffer> {
const db = this._getDB();
return db.execTransaction(async () => {
const tableNames: string[] = [];
const whereParts: string[] = [];
for (const colId of Object.keys(query.filters)) {
const values = query.filters[colId];
const tableName = `_grist_tmp_${tableNames.length}_${uuidv4().replace(/-/g, '_')}`;
await db.exec(`CREATE TEMPORARY TABLE ${tableName}(data)`);
for (const valuesChunk of chunk(values, maxSQLiteVariables)) {
const placeholders = valuesChunk.map(() => '(?)').join(',');
await db.run(`INSERT INTO ${tableName}(data) VALUES ${placeholders}`, valuesChunk);
}
whereParts.push(`${quoteIdent(query.tableId)}.${quoteIdent(colId)} IN (SELECT data FROM ${tableName})`);
}
const sql = this._getSqlForQuery(query, whereParts);
try {
return await db.allMarshal(sql);
} finally {
await Promise.all(tableNames.map(tableName => db.exec(`DROP TABLE ${tableName}`)));
}
});
}
/**
* Construct SQL for an ExpandedQuery. Expects that filters have been converted into
* a set of WHERE terms that should be ANDed.
*/
public _getSqlForQuery(query: ExpandedQuery, whereParts: string[]) {
const whereClause = whereParts.length > 0 ? `WHERE ${whereParts.join(' AND ')}` : '';
const limitClause = (typeof query.limit === 'number') ? `LIMIT ${query.limit}` : '';
const joinClauses = query.joins ? query.joins.join(' ') : '';
const selects = query.selects ? query.selects.join(', ') : '*';
const sql = `SELECT ${selects} FROM ${quoteIdent(query.tableId)} ` +
`${joinClauses} ${whereClause} ${limitClause}`;
return sql;
}
}
interface RebuildResult {