Postgres: Switch the datasource plugin from lib/pq to pgx (#83768)

postgres: switch from lib/pq to pgx

pkg/tsdb/grafana-postgresql-datasource/locker.go

@@ -1,85 +0,0 @@
-package postgres
-
-import (
-	"fmt"
-	"sync"
-)
-
-// locker is a named reader/writer mutual exclusion lock.
-// The lock for each particular key can be held by an arbitrary number of readers or a single writer.
-type locker struct {
-	locks   map[any]*sync.RWMutex
-	locksRW *sync.RWMutex
-}
-
-func newLocker() *locker {
-	return &locker{
-		locks:   make(map[any]*sync.RWMutex),
-		locksRW: new(sync.RWMutex),
-	}
-}
-
-// Lock locks named rw mutex with specified key for writing.
-// If the lock with the same key is already locked for reading or writing,
-// Lock blocks until the lock is available.
-func (lkr *locker) Lock(key any) {
-	lk, ok := lkr.getLock(key)
-	if !ok {
-		lk = lkr.newLock(key)
-	}
-	lk.Lock()
-}
-
-// Unlock unlocks named rw mutex with specified key for writing. It is a run-time error if rw is
-// not locked for writing on entry to Unlock.
-func (lkr *locker) Unlock(key any) {
-	lk, ok := lkr.getLock(key)
-	if !ok {
-		panic(fmt.Errorf("lock for key '%s' not initialized", key))
-	}
-	lk.Unlock()
-}
-
-// RLock locks named rw mutex with specified key for reading.
-//
-// It should not be used for recursive read locking for the same key; a blocked Lock
-// call excludes new readers from acquiring the lock. See the
-// documentation on the golang RWMutex type.
-func (lkr *locker) RLock(key any) {
-	lk, ok := lkr.getLock(key)
-	if !ok {
-		lk = lkr.newLock(key)
-	}
-	lk.RLock()
-}
-
-// RUnlock undoes a single RLock call for specified key;
-// it does not affect other simultaneous readers of locker for specified key.
-// It is a run-time error if locker for specified key is not locked for reading
-func (lkr *locker) RUnlock(key any) {
-	lk, ok := lkr.getLock(key)
-	if !ok {
-		panic(fmt.Errorf("lock for key '%s' not initialized", key))
-	}
-	lk.RUnlock()
-}
-
-func (lkr *locker) newLock(key any) *sync.RWMutex {
-	lkr.locksRW.Lock()
-	defer lkr.locksRW.Unlock()
-
-	if lk, ok := lkr.locks[key]; ok {
-		return lk
-	}
-	lk := new(sync.RWMutex)
-	lkr.locks[key] = lk
-	return lk
-}
-
-func (lkr *locker) getLock(key any) (*sync.RWMutex, bool) {
-	lkr.locksRW.RLock()
-	defer lkr.locksRW.RUnlock()
-
-	lock, ok := lkr.locks[key]
-	return lock, ok
-}