From 12827a1765b71feaef77cb3a99fae272e1a91f3f Mon Sep 17 00:00:00 2001 From: Andrew Bayer Date: Fri, 22 Jul 2011 20:03:29 +0000 Subject: [PATCH] MAPREDUCE-1224. Calling "SELECT t.* from AS t" to get meta information is too expensive for big tables. Contributed by Spencer Ho. From: Thomas White git-svn-id: https://svn.apache.org/repos/asf/incubator/sqoop/trunk@1149844 13f79535-47bb-0310-9956-ffa450edef68 --- src/java/org/apache/hadoop/sqoop/manager/SqlManager.java | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/src/java/org/apache/hadoop/sqoop/manager/SqlManager.java b/src/java/org/apache/hadoop/sqoop/manager/SqlManager.java index b710c6f3..fc9aafce 100644 --- a/src/java/org/apache/hadoop/sqoop/manager/SqlManager.java +++ b/src/java/org/apache/hadoop/sqoop/manager/SqlManager.java @@ -67,7 +67,8 @@ public SqlManager(final SqoopOptions opts) { * be tuned per-database, but the main extraction loop is still inheritable. */ protected String getColNamesQuery(String tableName) { - return "SELECT t.* FROM " + tableName + " AS t"; + // adding where clause to prevent loading a big table + return "SELECT t.* FROM " + tableName + " AS t WHERE 1=0"; } @Override