Apache9 commented on a change in pull request #4078:
URL: https://github.com/apache/hbase/pull/4078#discussion_r795177791
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File path:
hbase-client/src/main/java/org/apache/hadoop/hbase/MetaTableAccessor.java
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@@ -567,19 +569,55 @@ public static Scan getScanForTableName(Configuration
conf, TableName tableName)
// Stop key appends the smallest possible char to the table name
byte[] stopKey = getTableStopRowForMeta(tableName, QueryType.REGION);
- Scan scan = getMetaScan(conf, -1);
+ Scan scan = getMetaScan(null, conf, -1);
scan.setStartRow(startKey);
scan.setStopRow(stopKey);
return scan;
}
- private static Scan getMetaScan(Configuration conf, int rowUpperLimit) {
+ private static Scan getMetaScan(Connection conn, Configuration conf, int
rowUpperLimit) {
Scan scan = new Scan();
int scannerCaching = conf.getInt(HConstants.HBASE_META_SCANNER_CACHING,
HConstants.DEFAULT_HBASE_META_SCANNER_CACHING);
- if (conf.getBoolean(HConstants.USE_META_REPLICAS,
HConstants.DEFAULT_USE_META_REPLICAS)) {
- scan.setConsistency(Consistency.TIMELINE);
+
+ // Get the region locator's meta replica mode.
+ CatalogReplicaMode metaReplicaMode = CatalogReplicaMode.fromString(
+ conf.get(LOCATOR_META_REPLICAS_MODE,
CatalogReplicaMode.NONE.toString()));
+
+ switch (metaReplicaMode) {
+ case LOAD_BALANCE:
+ int numOfReplicas = 1;
+ if (conn != null) {
+ try {
+ try (Table metaTable = getMetaHTable(conn)) {
+ numOfReplicas = metaTable.getDescriptor().getRegionReplication();
Review comment:
Ah, this is a bit painful... We used to expect getMetaScan to only
contain memory operations but here we will have network io... And everytime we
call this method it will generate a rpc calll...
Looking at the code above, in the async code we also have this and we even
introduce a blocking rpc call. I haven't realized this when reviewing the PR
for master, but obviously it is incorrect, we should not do blocking call in
the async code. We should try to find a better way...
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