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Branching

PyroSQL branching works like Git branches, but for data. A branch is a lightweight, copy-on-write snapshot of the entire database. It can be queried and mutated independently of its parent, then either merged back or discarded — without affecting any other branch.

Because branches use copy-on-write storage, creating a branch is nearly instantaneous and consumes no additional disk space until rows are actually modified on the branch.

Use cases​

  • Feature branches — develop schema migrations or data transformations in isolation before promoting them to production.
  • Staging environments — give each developer or CI job its own live copy of production data without duplicating storage.
  • A/B testing — run two variants of an application against diverging data sets and merge the winning variant.
  • Safe bulk operations — run a destructive UPDATE or DELETE on a branch, verify the result, then merge; discard on failure.

PyroBranchManager​

PyroBranchManager is the entry point for all branch lifecycle operations. It requires a DBAL connection and a PyroSqlDriver instance, and all its methods assert that the connection is backed by PyroSQL before executing.

use Weaver\ORM\PyroSQL\Branch\PyroBranchManager;
use Weaver\ORM\PyroSQL\PyroSqlDriver;

$driver  = new PyroSqlDriver($connection);
$manager = new PyroBranchManager($connection, $driver);

create(string $name, string $from = 'main', ?DateTimeImmutable $asOf = null): PyroBranch​

Create a new branch from an existing one. By default branches off main at the current state. Pass $asOf to branch from a historical snapshot.

// Branch off the current state of main
$branch = $manager->create('feature/new-pricing');

// Branch off main as it existed on a specific date
$branch = $manager->create(
    name: 'audit/q1-snapshot',
    from: 'main',
    asOf: new \DateTimeImmutable('2024-03-31 23:59:59'),
);

Executes:

CREATE BRANCH "feature/new-pricing" FROM "main"
-- or
CREATE BRANCH "audit/q1-snapshot" FROM "main" AS OF TIMESTAMP '2024-03-31 23:59:59'

list(): PyroBranch[]​

Return all branches visible on the current connection, ordered by creation time ascending.

foreach ($manager->list() as $branch) {
    printf(
        "%-30s  parent: %-20s  created: %s\n",
        $branch->getName(),
        $branch->getParentName(),
        $branch->getCreatedAt()->format('Y-m-d H:i:s'),
    );
}

exists(string $name): bool​

Check whether a branch with the given name exists.

if (!$manager->exists('feature/new-pricing')) {
    $branch = $manager->create('feature/new-pricing');
}

delete(string $name): void​

Permanently drop a branch. Throws BranchNotFoundException if the branch does not exist.

$manager->delete('feature/old-experiment');

switch(string $name): void​

Switch the session context to the named branch. All subsequent queries on the current connection are routed to this branch until switched again.

$manager->switch('feature/new-pricing');

// All queries now read from / write to the feature/new-pricing branch
$products = $productRepo->query()->where('active', true)->get();

Executes:

SET pyrosql.branch = 'feature/new-pricing'

PyroBranch​

PyroBranch is a value object representing a branch. Obtain instances via PyroBranchManager::create() or PyroBranchManager::get().

connection(): Doctrine\DBAL\Connection​

Set the session context to this branch and return the DBAL connection. All subsequent queries on the returned connection are scoped to the branch.

$branch = $manager->create('feature/new-pricing');
$conn   = $branch->connection();

// Use $conn directly for raw queries on this branch
$conn->executeStatement("UPDATE products SET price = price * 1.05");

mergeTo(string $targetBranch = 'main'): void​

Merge this branch back into another branch (defaults to main). Changes made on the branch are applied to the target.

$branch->mergeTo('main');
// or merge into a different branch
$branch->mergeTo('staging');

Executes:

MERGE BRANCH "feature/new-pricing" INTO "main"

delete(): void​

Drop this branch permanently.

$branch->delete();

storageBytes(): int​

Returns the number of bytes consumed by this branch's copy-on-write delta versus its parent. A freshly created branch with no modifications returns 0.

$bytes = $branch->storageBytes();
printf("Branch %s uses %.2f MB of storage.\n", $branch->getName(), $bytes / 1_048_576);

Branch naming​

Branch names follow the same rules as PyroSQL identifiers. Names may contain letters, digits, hyphens, underscores, and forward slashes (e.g. feature/my-branch). Quoting is handled automatically by PyroBranchManager.

Full example: create a branch, modify data, merge back​

use Weaver\ORM\PyroSQL\Branch\PyroBranchManager;
use Weaver\ORM\PyroSQL\PyroSqlDriver;

$driver  = new PyroSqlDriver($connection);
$manager = new PyroBranchManager($connection, $driver);

// 1. Create a feature branch off main
$branch = $manager->create('feature/price-increase');

// 2. Switch the session to the branch
$branchConn = $branch->connection();

// 3. Make changes on the branch
$branchConn->executeStatement(
    "UPDATE products SET price = ROUND(price * 1.10, 2) WHERE category = 'electronics'"
);

// 4. Verify the changes look correct
$branchConn->executeStatement("SET pyrosql.branch = 'feature/price-increase'");
$affectedCount = (int) $branchConn->fetchOne(
    "SELECT COUNT(*) FROM products WHERE category = 'electronics'"
);
printf("Updated %d products on branch.\n", $affectedCount);

// 5. Check storage overhead
printf("Branch storage: %d bytes\n", $branch->storageBytes());

// 6a. Merge the branch into main if satisfied
$branch->mergeTo('main');
$branch->delete();

// 6b. Or just discard if not satisfied
// $branch->delete();