fix hangs create and restore when CLICKHOUSE_MAX_CONNECTIONS=0, fix

#933
Altinity · Jun 19, 2024 · 7707ecd · 7707ecd
1 parent 7e84f9f
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diff --git a/ChangeLog.md b/ChangeLog.md
@@ -1,3 +1,7 @@
+# v2.5.15
+BUG FIXES
+- fix hangs `create` and `restore` when CLICKHOUSE_MAX_CONNECTIONS=0, fix [933](https://github.com/Altinity/clickhouse-backup/issues/933)
+
 # v2.5.14
 IMPROVEMENTS
 - add http_send_timeout=300, http_receive_timeout=300 to embedded backup/restore operations

diff --git a/ReadMe.md b/ReadMe.md
@@ -77,8 +77,12 @@ A more detailed description is available here: https://www.youtube.com/watch?v=m
 
 ## Default Config
 
-By default, the config file is located at `/etc/clickhouse-backup/config.yml`, but it can be redefined via the `CLICKHOUSE_BACKUP_CONFIG` environment variable.
+By default, the config file is located at `/etc/clickhouse-backup/config.yml`, but it can be redefined via the `CLICKHOUSE_BACKUP_CONFIG` environment variable or via `--config` command line parameter.
 All options can be overwritten via environment variables.
+Use `clickhouse-backup default-config` to print default config.
+
+## Explain config parameters
+following values is not default, it just explain which each config parameter actually means
 Use `clickhouse-backup print-config` to print current config.
 
 ```yaml

diff --git a/pkg/backup/create.go b/pkg/backup/create.go
@@ -255,7 +255,7 @@ func (b *Backuper) createBackupLocal(ctx context.Context, backupName, diffFromRe
 	var backupDataSize, backupObjectDiskSize, backupMetadataSize uint64
 	var metaMutex sync.Mutex
 	createBackupWorkingGroup, createCtx := errgroup.WithContext(ctx)
-	createBackupWorkingGroup.SetLimit(b.cfg.ClickHouse.MaxConnections)
+	createBackupWorkingGroup.SetLimit(max(b.cfg.ClickHouse.MaxConnections,1))
 
 	var tableMetas []metadata.TableTitle
 	for tableIdx, tableItem := range tables {

diff --git a/pkg/backup/restore.go b/pkg/backup/restore.go
@@ -1196,7 +1196,7 @@ func (b *Backuper) restoreDataRegular(ctx context.Context, backupName string, ba
 		return fmt.Errorf("%s is not created. Restore schema first or create missing tables manually", strings.Join(missingTables, ", "))
 	}
 	restoreBackupWorkingGroup, restoreCtx := errgroup.WithContext(ctx)
-	restoreBackupWorkingGroup.SetLimit(b.cfg.ClickHouse.MaxConnections)
+	restoreBackupWorkingGroup.SetLimit(max(b.cfg.ClickHouse.MaxConnections,1))
 
 	for i := range tablesForRestore {
 		tableRestoreStartTime := time.Now()