[GitHub] [ignite] AMashenkov commented on a change in pull request #6529: IGNITE-11756: SQL: implement a table row count statistics for the local queries.

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AMashenkov commented on a change in pull request #6529: IGNITE-11756: SQL: implement a table row count statistics for the local queries.
URL: https://github.com/apache/ignite/pull/6529#discussion_r283241232
 
 

 ##########
 File path: modules/indexing/src/main/java/org/apache/ignite/internal/processors/query/h2/opt/GridH2Table.java
 ##########
 @@ -1423,4 +1439,62 @@ long version() {
             return ver;
         }
     }
+
+    /**
+     * Table statistics.
+     */
+    public class TableStatistics {
+        /** */
+        private volatile long rowCntStats;
+
+        /** */
+        private volatile long lastSeenTblRowCnt;
+
+        /**
+         * @return Row count statistics.
+         */
+        public long getRowCountStatistics() {
+            QueryContext qctx = rowDescriptor().indexing().queryContextRegistry().getThreadLocal();
+
+            assert qctx != null;
+
+            if (!qctx.local())
+                return 10_000; // Fallback to the previous behavior for distributed queries.
+
+            long curTblRowCnt = getRowCountApproximation();
+
+            // If a table size hasn't been changed since the last call - return the previous value.
+            if (lastSeenTblRowCnt == curTblRowCnt)
+                return rowCntStats;
+
+            lastSeenTblRowCnt = curTblRowCnt;
+
+            GridCacheContext cctx = cacheInfo().cacheContext();
+
+            if (cctx == null) // Cache is not started.
+                return 0;
+
+            // Calculate new row count statistics.
+            long cnt = 0;
+
+            if (cctx.isReplicated())
+                cnt = getRowCountApproximation(); // Count all entries for replicated caches.
+            else {
+                // Consider only primary partitions for partitioned caches.
+                IndexingQueryFilter f = qctx.filter();
+                IndexingQueryCacheFilter filter = f != null ? f.forCache(cacheName()) : null;
+
+                for (IgniteCacheOffheapManager.CacheDataStore store : cctx.offheap().cacheDataStores()) {
 
 Review comment:
   I'm not sure this is correct way.
   GridDhtCacheAdapter uses topology().currentLocalPartitions() for size calculation to filter out Evicted parts.
   Please, recheck this.

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