Object statistics lru by sharpsalt · Pull Request #11 · sharpsalt/Velox-In-Memory-Database

sharpsalt · 2026-04-23T00:41:41Z

No description provided.

…l(),evictAllKeysLRU()

Copilot

Pull request overview

This PR appears to introduce Redis-like keyspace statistics plus an approximated-LRU eviction strategy by tracking object last-access time and moving expiry metadata into a separate expires dictionary.

Changes:

Adds last-access tracking (LastAccessedAt) to objects to support LRU-style eviction.
Introduces an expires dictionary with helper functions to manage expiry outside the object.
Adds eviction-pool/LRU eviction scaffolding and keyspace stats/INFO reporting hooks.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 23 comments.

Show a summary per file

File	Description
core/store.go	Adds global `expires` map usage, updates Put/Get/Del to track access + stats and consult expiry.
core/stats.go	Introduces `KeyspaceStat` structure and a DB-stat update helper.
core/object.go	Replaces per-object `ExpiresAt` with `LastAccessedAt` for LRU tracking.
core/expire.go	Adds helpers (`hasExpired`, `getExpiry`) for the new `expires` map.
core/evictionpool.go	New eviction pool implementation intended for approximated LRU.
core/eviction.go	Adds eviction strategy switching and approximated LRU clock/idle calculations.
core/eval.go	Updates GET/TTL/EXPIRE behavior around expiry and adds INFO dispatch.
config/main.go	Adds new config definitions for limits and eviction strategy.

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Copilot · 2026-04-23T00:46:19Z

+//TODO: no need to populate everytime, should populate 
+//only when the number of keys to evict is less than what we have in the pool
+funct evictAllKeysLRU(){
+	populateEvictionPool()
+	evictCount:=int16(config.EvictionRatio=float64(config.KeysLimit))
+	for i:=;i<int(evictCount) && len(ePool.pool)>0 ;i++{
+		item:=ePool.Pop()
+		if item==nil{
+			return
+		}
+		Del(item.key)
+	}
+}


evictAllKeysLRU has several syntax/type errors (funct, invalid evictCount assignment expression, malformed for loop initializer). As written, the LRU eviction path will not compile; fix the function signature and compute evictCount as EvictionRatio * KeysLimit similar to evictAllKeysRandom.

Copilot · 2026-04-23T00:46:19Z

+		evictfirst()
+	case "allkets-random":
+		evictAllkeysRandom()
+	case: "allkeys-lru":


The evict switch has invalid Go syntax and mismatched function names/strategy strings (evictfirst vs evictFirst, allkets-random, case:). This will not compile and also won’t match the configured strategy values; fix case labels and call the correct functions.

Suggested change

evictfirst()

case "allkets-random":

evictAllkeysRandom()

case: "allkeys-lru":

evictFirst()

case "allkeys-random":

evictAllKeysRandom()

case "allkeys-lru":

Copilot · 2026-04-23T00:46:19Z

+		case "CLIENT":
+			buf.Write(evalCLIENT(cmd.Args))
+		case "LATENCY":
+			buf.Write(evalLATENCY(cmd.Args))


EvalAndRespond adds cases for CLIENT and LATENCY, but evalCLIENT/evalLATENCY are not defined anywhere in core. This will not compile; either implement these handlers or remove the switch cases.

Suggested change

case "CLIENT":

buf.Write(evalCLIENT(cmd.Args))

case "LATENCY":

buf.Write(evalLATENCY(cmd.Args))

Copilot · 2026-04-23T00:46:20Z

@@ -62,16 +78,21 @@ func Get(k string) *Obj{
 			periodicaly it is mvoing forward and sample randomly 20 keys and seees the expiration and delete the required one
 			and phir se whi loop chalao 
 			*/
-			delete(store,k)
-			return nil
+			if hasExpired(v){
+				Del(k)
+			    return nil
+			}
 		}
 	}
+	v.LastAccessedAt=getCurrentClock()
 	return v


Get sets v.LastAccessedAt = ... unconditionally at the end. If the key doesn't exist (v == nil), this will panic at runtime. Only update LastAccessedAt after confirming v != nil (and after handling expiry/deletion).

Copilot · 2026-04-23T00:46:20Z

+	it gives me current clock and if it is greater than lastaccessedat then for anytimestamp  then diff, other (max-last)*c
+	*/
+	c:=getCurrentClock()
+	if c>=LastAccessdAt{
+		return c-LastAccessdAt
+	}
+	return (0x00FFFFF-LastAccessdAt)*c


getIdleTime wrap-around path returns (mask-last)*c, which multiplies two time values and produces meaningless/overflow-prone results. For a wrapping clock, the idle time should be computed as the remaining ticks until wrap plus the current tick value (i.e., an addition-based wrap calculation).

Suggested change

it gives me current clock and if it is greater than lastaccessedat then for anytimestamp then diff, other (max-last)*c

*/

c:=getCurrentClock()

if c>=LastAccessdAt{

return c-LastAccessdAt

}

return (0x00FFFFF-LastAccessdAt)*c

it gives me current clock and if it is greater than lastaccessedat then for anytimestamp then diff,

otherwise the elapsed time is the remaining ticks until wrap plus the current tick value

*/

c:=getCurrentClock()

if c>=LastAccessdAt{

return c-LastAccessdAt

}

return (0x00FFFFF-LastAccessdAt) + c + 1

Copilot · 2026-04-23T00:46:23Z

+func populateEvictionPool(){
+	sampleSize:=5
+	for k:=range store{
+		ePool.Push(k,store[k].lastaccessedat)
+		sampleSize--
+		if sampleSize==0{
+			break
+		}
+	}


populateEvictionPool references store[k].lastaccessedat, but the field on Obj is LastAccessedAt (exported) and PoolItem uses a different name as well. This mismatch will not compile; align field names and casing across Obj, PoolItem, and call sites.

Copilot · 2026-04-23T00:46:23Z

 	//if key already expired then return nil
 	if obj.ExpiresAt!=-1 && obj.ExpiresAt<=time.Now().UnixMilli(){
 		// c.Write(RESP_NIL)
 		// return nil
 		return RESP_NIL
 	}


evalGET still references obj.ExpiresAt, but Obj no longer defines that field. This will not compile; remove the ExpiresAt checks and rely on the new expires map via hasExpired (and ensure expired keys are deleted so subsequent operations behave like Redis).

Copilot · 2026-04-23T00:46:24Z

+	exp.isExpirySet:=getExpiry(obj)
+	if !isExpirySet{
+		return RESP_MINUS_1
+	}
+
+	//if key expired i.e key does not exist hence return -2
+	if uint64(time.Now().UnixMilli())>exp{
+		return RESP_MINUS_2
+	}
+
+	//compute the time remaining for the key to expire and 
+	//return the RESP encoded form of it 
+	durationMS:=exp-uint64(time.Now().UnixMilli())
+
 	// c.Write(Encode(int64(durationMS/1000),false))
 	// return nil
 	return Encode(int64(durationMs/1000), false)


The new TTL logic has invalid Go syntax and name mismatches: exp.isExpirySet:=getExpiry(obj) should destructure into two variables, and the function mixes durationMS/durationMs. As written, this block will not compile and will return the wrong value; fix tuple assignment and use one duration variable consistently.

Copilot · 2026-04-23T00:46:24Z

 import (
 	"time"
-
+	"store.go"


import ( ... "store.go" ... ) is an invalid import path in Go and will fail to compile. Remove this import; if the intent was to reference types/functions in the same package, no import is needed.

Suggested change

"store.go"

Copilot · 2026-04-23T00:46:24Z

+func (pq *EvictionPool) Push(key string,lastaccessedat uint32){
+	_,ok:=pq.keyset[key]
+	if ok{
+		//while pushing it into eviction pool if it already exists then we don;t have to push it again it in eveiction pool
+		return
+	}
+	ietm:=&PoolItem(key:key,lastaccessedat:lastaccessedat)
+	if len(pq.pool)<ePoolSizeMax{
+		//which means there is some space for adding element
+		//remeber eviction pool is needed to be sorted by idle time
+		pq.keyset[key]=items
+		pq.pool=append(pq.pool,item)
+
+
+		//Performance bottleneck
+		sort.Sort(ByIdleTime(pq.pool))
+	}else if lastaccessedat>pq.pool[len(pq.pool)-1].lastaccessedat{
+		//if i have no space in eviction pool but the element which i have smapled is worse than my current 
+		//i will create space for that by removing the 1st one and adding new element by appending it 
+		///so this way we are ensuring that our pool contains best possible candidates to be evcited
+		pq.pool=pq.pool[1:]
+		pq.keyset[key]=item
+		pq.pool=append(pq.pool,item)
+	}


Push contains multiple identifier/syntax issues that prevent compilation (&PoolItem(key:key,...), ietm vs item, items undefined, etc.). Clean up the composite literal and use a single consistently-named *PoolItem variable when updating keyset and appending to pool.

sharpsalt added 9 commits April 18, 2026 12:34

feat: Implemented evictallkeysrandom

ca4a02d

feat: Implemented INFI,CLIENT,LATENCY of eval each

4ca2614

feat: Implemented getCurrentClock(),getIdleTime(),populateEvictionPoo…

ca9034b

…l(),evictAllKeysLRU()

feat: Implemented hasExpire()

f3b6d91

feat: replaced ExpireAt with LastAccessedAt

6f55d55

feat: Implemented setExpiry

d7cdaa9

feat: setted up configfor eviction,aof,keyslimit,etc

461c28c

feat: Implemented evictionPool from scratch

a0f4405

feat: Implemented UpdateDBState

d5e620d

Copilot AI review requested due to automatic review settings April 23, 2026 00:41

Copilot started reviewing on behalf of sharpsalt April 23, 2026 00:42 View session

sharpsalt merged commit 6edf885 into main Apr 23, 2026
2 of 3 checks passed

Copilot AI reviewed Apr 23, 2026

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Object statistics lru#11

Object statistics lru#11
sharpsalt merged 9 commits intomainfrom
ObjectStatisticsLRU

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Pull request overview

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