Implement heirarchical query for getting previous entity (#216)

* Implement heirarchical query for getting previous entity.

* Check entity id in hierarchical query to limit number of recursions.

Co-authored-by: nabarun <nabarun@deepstacksoft.com>
This commit is contained in:
Ashwin Phatak 2021-08-16 17:55:23 +05:30 committed by GitHub
parent 9e1ed70d18
commit 23bfcc02dc
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3 changed files with 184 additions and 28 deletions

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@ -0,0 +1,87 @@
# database
## Hierarchical Queries
For fetching previous entity that would be updated at a particular blockHash, we need to traverse the parent hashes. As the same entity might be present on a different branch chain with different values. These branches occur in the frothy region and so a recursive query is done to get the blockHash of the previous entity in this region.
Let the blockHash be `0xBlockHash` and the entity id be `entityId`, then the hierarchical query is
```pgsql
WITH RECURSIVE cte_query AS
(
SELECT
b.block_hash,
b.block_number,
b.parent_hash,
1 as depth,
e.id
FROM
block_progress b
LEFT JOIN
entityTable e ON e.block_hash = b.block_hash
WHERE
b.block_hash = '0xBlockHash'
UNION ALL
SELECT
b.block_hash,
b.block_number,
b.parent_hash,
c.depth + 1,
e.id
FROM
block_progress b
LEFT JOIN
${repo.metadata.tableName} e
ON e.block_hash = b.block_hash
AND e.id = 'entityId'
INNER JOIN
cte_query c ON c.parent_hash = b.block_hash
WHERE
c.id IS NULL AND c.depth < 16
)
SELECT
block_hash, block_number, id
FROM
cte_query
ORDER BY block_number ASC
LIMIT 1;
```
The second WHERE clause checks that the loop continues only till MAX_REORG_DEPTH `16` which specifies the frothy region or stop when the entity is found.
The resulting blockHash is then used to fetch the previous entity.
For fetching multiple entities, we fetch all the blockHashes in the frothy region. So it fetches the entities from the correct branch in the frothy and then from the pruned region.
Hierarchical query for getting blockHashes in the frothy region
```pgsql
WITH RECURSIVE cte_query AS
(
SELECT
block_hash,
block_number,
parent_hash,
1 as depth
FROM
block_progress
WHERE
block_hash = '0xBlockHash'
UNION ALL
SELECT
b.block_hash,
b.block_number,
b.parent_hash,
c.depth + 1
FROM
block_progress b
INNER JOIN
cte_query c ON c.parent_hash = b.block_hash
WHERE
c.depth < 16
)
SELECT
block_hash, block_number
FROM
cte_query;
```

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@ -3,7 +3,7 @@
//
import assert from 'assert';
import { Brackets, Connection, ConnectionOptions, createConnection, DeepPartial, FindConditions, FindOneOptions, In, LessThanOrEqual, QueryRunner, Repository } from 'typeorm';
import { Brackets, Connection, ConnectionOptions, createConnection, DeepPartial, FindConditions, FindOneOptions, LessThanOrEqual, QueryRunner, Repository } from 'typeorm';
import { SnakeNamingStrategy } from 'typeorm-naming-strategies';
import { MAX_REORG_DEPTH } from '@vulcanize/util';
@ -458,7 +458,7 @@ export class Database {
.where(`subTable.id = ${tableName}.id`);
if (block.hash) {
const { canonicalBlockNumber, blockHashes } = await this._getBranchInfo(queryRunner, block.hash);
const { canonicalBlockNumber, blockHashes } = await this._getFrothyRegion(queryRunner, block.hash);
subQuery = subQuery
.andWhere(new Brackets(qb => {
@ -783,38 +783,107 @@ export class Database {
}
async _getPrevEntityVersion<Entity> (queryRunner: QueryRunner, repo: Repository<Entity>, findOptions: { [key: string]: any }): Promise<Entity | undefined> {
// Check whether query is ordered by blockNumber to get the latest entity.
assert(findOptions.order.blockNumber);
const { canonicalBlockNumber, blockHashes } = await this._getBranchInfo(queryRunner, findOptions.where.blockHash);
findOptions.where.blockHash = In(blockHashes);
let entity = await repo.findOne(findOptions);
if (!entity) {
delete findOptions.where.blockHash;
findOptions.where.blockNumber = LessThanOrEqual(canonicalBlockNumber);
entity = await repo.findOne(findOptions);
// Hierarchical query for getting the entity in the frothy region.
// TODO: Use syncStatus.latestCanonicalBlockNumber instead of MAX_REORG_DEPTH after pruning is implemented.
const heirerchicalQuery = `
WITH RECURSIVE cte_query AS
(
SELECT
b.block_hash,
b.block_number,
b.parent_hash,
1 as depth,
e.id
FROM
block_progress b
LEFT JOIN
${repo.metadata.tableName} e ON e.block_hash = b.block_hash
WHERE
b.block_hash = $1
UNION ALL
SELECT
b.block_hash,
b.block_number,
b.parent_hash,
c.depth + 1,
e.id
FROM
block_progress b
LEFT JOIN
${repo.metadata.tableName} e
ON e.block_hash = b.block_hash
AND e.id = $2
INNER JOIN
cte_query c ON c.parent_hash = b.block_hash
WHERE
c.id IS NULL AND c.depth < $3
)
SELECT
block_hash, block_number, id
FROM
cte_query
ORDER BY block_number ASC
LIMIT 1;
`;
// Fetching blockHash for previous entity in frothy region.
const [{ block_hash: blockHash, block_number: blockNumber, id }] = await queryRunner.query(heirerchicalQuery, [findOptions.where.blockHash, findOptions.where.id, MAX_REORG_DEPTH]);
if (id) {
// Entity found in frothy region.
findOptions.where.blockHash = blockHash;
return repo.findOne(findOptions);
}
return entity;
// If entity not found in frothy region get latest entity in the pruned region.
delete findOptions.where.blockHash;
const canonicalBlockNumber = blockNumber + 1;
findOptions.where.blockNumber = LessThanOrEqual(canonicalBlockNumber);
return repo.findOne(findOptions);
}
async _getBranchInfo (queryRunner: QueryRunner, blockHash: string): Promise<{ canonicalBlockNumber: number, blockHashes: string[] }> {
const blockRepo = queryRunner.manager.getRepository(BlockProgress);
let block = await blockRepo.findOne({ blockHash });
assert(block);
async _getFrothyRegion (queryRunner: QueryRunner, blockHash: string): Promise<{ canonicalBlockNumber: number, blockHashes: string[] }> {
// TODO: Use syncStatus.latestCanonicalBlockNumber instead of MAX_REORG_DEPTH after pruning is implemented.
const heirerchicalQuery = `
WITH RECURSIVE cte_query AS
(
SELECT
block_hash,
block_number,
parent_hash,
1 as depth
FROM
block_progress
WHERE
block_hash = $1
UNION ALL
SELECT
b.block_hash,
b.block_number,
b.parent_hash,
c.depth + 1
FROM
block_progress b
INNER JOIN
cte_query c ON c.parent_hash = b.block_hash
WHERE
c.depth < $2
)
SELECT
block_hash, block_number
FROM
cte_query;
`;
// TODO: Should be calcualted from chainHeadBlockNumber?
const canonicalBlockNumber = block.blockNumber - MAX_REORG_DEPTH;
// Get blocks in the frothy region using heirarchical query.
const blocks = await queryRunner.query(heirerchicalQuery, [blockHash, MAX_REORG_DEPTH]);
const blockHashes = blocks.map(({ block_hash: blockHash }: any) => blockHash);
const syncStatus = await this.getSyncStatus(queryRunner);
assert(syncStatus);
const blockHashes = [block.blockHash];
while (block.blockNumber > canonicalBlockNumber && block.blockNumber > syncStatus.latestCanonicalBlockNumber) {
blockHash = block.parentHash;
block = await blockRepo.findOne({ blockHash });
assert(block);
blockHashes.push(block.blockHash);
}
// Canonical block is the block after the last block in frothy region.
const canonicalBlockNumber = blocks[blocks.length - 1].block_number + 1;
return { canonicalBlockNumber, blockHashes };
}

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@ -260,7 +260,7 @@ export class Indexer {
let res;
try {
res = this._db.getBundle(dbTx, { id, blockHash: block.hash, blockNumber: block.number });
res = await this._db.getBundle(dbTx, { id, blockHash: block.hash, blockNumber: block.number });
await dbTx.commitTransaction();
} catch (error) {
await dbTx.rollbackTransaction();
@ -294,7 +294,7 @@ export class Indexer {
let res;
try {
res = this._db.getToken(dbTx, { id, blockHash: block.hash, blockNumber: block.number });
res = await this._db.getToken(dbTx, { id, blockHash: block.hash, blockNumber: block.number });
await dbTx.commitTransaction();
} catch (error) {
await dbTx.rollbackTransaction();