Merge pull request #2382 from CortexFoundation/dev

adjust memory table size

Author: ucwong

ctxcdb/pebble/pebble.go

@@ -164,9 +164,12 @@ func New(file string, cache int, handles int, namespace string, readonly bool) (
 	// Taken from https://github.com/cockroachdb/pebble/blob/master/internal/constants/constants.go
 	maxMemTableSize := (1<<31)<<(^uint(0)>>63) - 1
 
-	// Two memory tables is configured which is identical to leveldb,
-	// including a frozen memory table and another live one.
-	memTableLimit := 2
+	// Four memory tables are configured, each with a default size of 256 MB.
+	// Having multiple smaller memory tables while keeping the total memory
+	// limit unchanged allows writes to be flushed more smoothly. This helps
+	// avoid compaction spikes and mitigates write stalls caused by heavy
+	// compaction workloads.
+	memTableLimit := 4
 	memTableSize := cache * 1024 * 1024 / 2 / memTableLimit
 	if memTableSize > maxMemTableSize {
 		memTableSize = maxMemTableSize - 1