UBERF-8122: Fix backup service

Signed-off-by: Andrey Sobolev <haiodo@gmail.com>

server/postgres/src/storage.ts

@@ -18,6 +18,7 @@ import core, {
   type AttachedDoc,
   type Class,
   type Doc,
+  type DocInfo,
   type DocumentQuery,
   type DocumentUpdate,
   type Domain,
@@ -941,12 +942,12 @@ abstract class PostgresAdapterBase implements DbAdapter {
       )
     }
 
-    const next = async (): Promise<Doc | null> => {
-      const result = await client.query(`FETCH 1 FROM ${cursorName}`)
+    const next = async (limit: number): Promise<Doc[]> => {
+      const result = await client.query(`FETCH ${limit} FROM ${cursorName}`)
       if (result.rows.length === 0) {
-        return null
+        return []
       }
-      return result.rows[0] !== undefined ? parseDoc(result.rows[0]) : null
+      return result.rows.filter((it) => it != null).map((it) => parseDoc(it))
     }
 
     const flush = async (flush = false): Promise<void> => {
@@ -975,47 +976,51 @@ abstract class PostgresAdapterBase implements DbAdapter {
           await init('_id, data', "data ->> '%hash%' IS NOT NULL AND data ->> '%hash%' <> ''")
           initialized = true
         }
-        let d = await ctx.with('next', { mode }, async () => await next())
-        if (d == null && mode === 'hashed') {
+        let docs = await ctx.with('next', { mode }, async () => await next(50))
+        if (docs.length === 0 && mode === 'hashed') {
           await close(cursorName)
           mode = 'non_hashed'
           await init('*', "data ->> '%hash%' IS NULL OR data ->> '%hash%' = ''")
-          d = await ctx.with('next', { mode }, async () => await next())
+          docs = await ctx.with('next', { mode }, async () => await next(50))
         }
-        if (d == null) {
-          return undefined
+        if (docs.length === 0) {
+          return []
         }
-        let digest: string | null = (d as any)['%hash%']
-        if ('%hash%' in d) {
-          delete d['%hash%']
-        }
-        const pos = (digest ?? '').indexOf('|')
-        if (digest == null || digest === '') {
-          const cs = ctx.newChild('calc-size', {})
-          const size = estimateDocSize(d)
-          cs.end()
-
-          const hash = createHash('sha256')
-          updateHashForDoc(hash, d)
-          digest = hash.digest('base64')
-
-          bulkUpdate.set(d._id, `${digest}|${size.toString(16)}`)
-
-          await ctx.with('flush', {}, async () => {
-            await flush()
-          })
-          return {
-            id: d._id,
-            hash: digest,
-            size
+        const result: DocInfo[] = []
+        for (const d of docs) {
+          let digest: string | null = (d as any)['%hash%']
+          if ('%hash%' in d) {
+            delete d['%hash%']
           }
-        } else {
-          return {
-            id: d._id,
-            hash: digest.slice(0, pos),
-            size: parseInt(digest.slice(pos + 1), 16)
+          const pos = (digest ?? '').indexOf('|')
+          if (digest == null || digest === '') {
+            const cs = ctx.newChild('calc-size', {})
+            const size = estimateDocSize(d)
+            cs.end()
+
+            const hash = createHash('sha256')
+            updateHashForDoc(hash, d)
+            digest = hash.digest('base64')
+
+            bulkUpdate.set(d._id, `${digest}|${size.toString(16)}`)
+
+            await ctx.with('flush', {}, async () => {
+              await flush()
+            })
+            result.push({
+              id: d._id,
+              hash: digest,
+              size
+            })
+          } else {
+            result.push({
+              id: d._id,
+              hash: digest.slice(0, pos),
+              size: parseInt(digest.slice(pos + 1), 16)
+            })
           }
         }
+        return result
       },
       close: async () => {
         await ctx.with('flush', {}, async () => {