From 3178843b72aa14239d044d3f39a0d34bf9092438 Mon Sep 17 00:00:00 2001
From: Minglei Jin <mljin@taosdata.com>
Date: Tue, 10 Jan 2023 10:11:17 +0800
Subject: [PATCH 1/2] tsdb/cache: reseek with busy always

---
 source/dnode/vnode/src/tsdb/tsdbCacheRead.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/source/dnode/vnode/src/tsdb/tsdbCacheRead.c b/source/dnode/vnode/src/tsdb/tsdbCacheRead.c
index 1c1626ba5c..1eea398fdf 100644
--- a/source/dnode/vnode/src/tsdb/tsdbCacheRead.c
+++ b/source/dnode/vnode/src/tsdb/tsdbCacheRead.c
@@ -208,13 +208,21 @@ static int32_t tsdbCacheQueryReseek(void* pQHandle) {
   int32_t           code = 0;
   SCacheRowsReader* pReader = pQHandle;
 
-  taosThreadMutexLock(&pReader->readerMutex);
+  code = taosThreadMutexTryLock(&pReader->readerMutex);
+  if (code == 0) {
+    // pause current reader's state if not paused, save ts & version for resuming
+    // just wait for the big all tables' snapshot untaking for now
 
-  // pause current reader's state if not paused, save ts & version for resuming
-  // just wait for the big all tables' snapshot untaking for now
+    code = TSDB_CODE_VND_QUERY_BUSY;
 
-  taosThreadMutexUnlock(&pReader->readerMutex);
-  return code;
+    taosThreadMutexUnlock(&pReader->readerMutex);
+
+    return code;
+  } else if (code == EBUSY) {
+    return TSDB_CODE_VND_QUERY_BUSY;
+  } else {
+    return -1;
+  }
 }
 
 int32_t tsdbRetrieveCacheRows(void* pReader, SSDataBlock* pResBlock, const int32_t* slotIds, SArray* pTableUidList) {

From d69ec98723f91af0d149aca37428d62c68f4a515 Mon Sep 17 00:00:00 2001
From: Minglei Jin <mljin@taosdata.com>
Date: Tue, 10 Jan 2023 10:38:44 +0800
Subject: [PATCH 2/2] tsdb/read: reseek with try lock mutex

---
 source/dnode/vnode/src/tsdb/tsdbRead.c | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/source/dnode/vnode/src/tsdb/tsdbRead.c b/source/dnode/vnode/src/tsdb/tsdbRead.c
index 68e6a0d86b..785243d365 100644
--- a/source/dnode/vnode/src/tsdb/tsdbRead.c
+++ b/source/dnode/vnode/src/tsdb/tsdbRead.c
@@ -4068,18 +4068,23 @@ static int32_t tsdbSetQueryReseek(void* pQHandle) {
   int32_t      code = 0;
   STsdbReader* pReader = pQHandle;
 
-  taosThreadMutexLock(&pReader->readerMutex);
+  code = taosThreadMutexTryLock(&pReader->readerMutex);
+  if (code == 0) {
+    if (pReader->suspended) {
+      taosThreadMutexUnlock(&pReader->readerMutex);
+      return code;
+    }
+
+    tsdbReaderSuspend(pReader);
 
-  if (pReader->suspended) {
     taosThreadMutexUnlock(&pReader->readerMutex);
+
     return code;
+  } else if (code == EBUSY) {
+    return TSDB_CODE_VND_QUERY_BUSY;
+  } else {
+    return -1;
   }
-
-  tsdbReaderSuspend(pReader);
-
-  taosThreadMutexUnlock(&pReader->readerMutex);
-
-  return code;
 }
 
 int32_t tsdbReaderResume(STsdbReader* pReader) {