External Materialization interleaving loads SYSADMIN.loadMatView ---------------------------------------------------------------- Key: TEIID-4283 URL: https://issues.jboss.org/browse/TEIID-4283 Project: Teiid Issue Type: Bug Components: Query Engine Affects Versions: 8.12.5 Reporter: Jan Stastny Assignee: Steven Hawkins Priority: Blocker Fix For: 9.1, 8.12.5, 9.0.1 Attachments: jdg-log.txt There is a possibility of two concurrent loads of single materialized view when using SYSADMIN.loadMatView function. I observed the issue while: # Waiting for ttl-driven reload and in right time I triggered another load explicitly by invoking the loadMatView function. # Invoking SYSADMIN.loadMatView function multiple times in quick succession. The view definition: {code:sql} CREATE VIEW external_long_ttl ( customer_id integer NOT NULL, total_amount integer ) OPTIONS (MATERIALIZED 'TRUE', UPDATABLE 'FALSE', MATERIALIZED_TABLE 'Source.JSTASTNY.dv_matviews_mat_view', "teiid_rel:ALLOW_MATVIEW_MANAGEMENT" 'true', "teiid_rel:MATVIEW_STATUS_TABLE" 'Source.JSTASTNY.dv_matviews_statustable', "teiid_rel:ON_VDB_START_SCRIPT" 'MERGE INTO dv_matviews_check_table(id,vdb_create) SELECT id, vdb_create+1 FROM dv_matviews_check_table WHERE id=''external_long_ttl'';', "teiid_rel:ON_VDB_DROP_SCRIPT" 'MERGE INTO dv_matviews_check_table(id,vdb_drop) SELECT id, vdb_drop+1 FROM dv_matviews_check_table WHERE id=''external_long_ttl'';', "teiid_rel:MATVIEW_LOAD_SCRIPT" 'INSERT INTO dv_matviews_mat_view_stage(customer_id,total_amount) SELECT CONVERT(c.id,integer) AS customer_id, CONVERT(SUM(o.amount),integer) AS total_amount FROM dv_matviews_customers c INNER JOIN dv_matviews_orders o ON c.id = o.customer_id GROUP BY c.id;', "teiid_rel:MATVIEW_BEFORE_LOAD_SCRIPT" 'exec Source.native(''truncate table ${db.table.prefix}dv_matviews_mat_view_stage'');MERGE INTO dv_matviews_check_table(id,before_load) SELECT id, before_load+1 FROM dv_matviews_check_table WHERE id=''external_long_ttl'';', "teiid_rel:MATVIEW_AFTER_LOAD_SCRIPT" 'exec Source.native(''RENAME TABLE ${db.table.prefix}dv_matviews_mat_view_stage TO ${db.table.prefix}dv_matviews_mat_view_temp'');exec Source.native(''RENAME TABLE ${db.table.prefix}dv_matviews_mat_view TO ${db.table.prefix}dv_matviews_mat_view_stage'');exec Source.native(''RENAME TABLE ${db.table.prefix}dv_matviews_mat_view_temp TO ${db.table.prefix}dv_matviews_mat_view'');MERGE INTO dv_matviews_check_table(id,after_load) SELECT id, after_load+1 FROM dv_matviews_check_table WHERE id=''external_long_ttl'';', "teiid_rel:MATVIEW_ONERROR_ACTION" 'WAIT', "teiid_rel:MATVIEW_TTL" 20000) AS SELECT CONVERT(c.id,integer) AS customer_id, CONVERT(SUM(o.amount),integer) AS total_amount FROM dv_matviews_customers c INNER JOIN dv_matviews_orders o ON c.id = o.customer_id GROUP BY c.id; {code} Query to explicitly load the view: {code:sql} exec SYSADMIN.loadMatView(schemaName=>'View',viewname=>'external_long_ttl', invalidate=>'true') {code} I attached a log which starts with ttl-driven load, then the explicit load is performed. The issue noticed is in teiid_rel:MATVIEW_AFTER_LOAD_SCRIPT , where primary and staging tables are being swapped. The second load (explicit) can't find the original table, as the ttl-driven load had already renamed it. But this situation of two concurrent loads should never occur.