[DRILL-8372] Unfreed buffers when running a LIMIT 0 query over delimited text

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.21.0
• Fix Version/s: 1.21.0
• Component/s: Storage - Text & CSV
• Assignee: James Turton
• Reporter: James Turton
• Created: 20/Dec/22 14:01
• Updated: 08/Feb/23 07:44
• Resolved: 08/Feb/23 07:16

Description

With the following data layout

/tmp/foo
 ├──a
 │  └──test_data.csvh
 └──b
    └──test_data.csvh 

a LIMIT 0 query over it results in unfreed buffer errors.

apache drill (dfs.tmp)> select * from `foo` limit 0;
Error: SYSTEM ERROR: IllegalStateException: Allocator[op:0:0:4:EasySubScan] closed with outstanding buffers allocated (3).
Allocator(op:0:0:4:EasySubScan) 1000000/299008/3182592/10000000000 (res/actual/peak/limit)
  child allocators: 0
  ledgers: 3
    ledger[113] allocator: op:0:0:4:EasySubScan), isOwning: true, size: 262144, references: 1, life: 277785186322881..0, allocatorManager: [109, life: 277785186258906..0] holds 1 buffers.
        DrillBuf[142], udle: [110 0..262144]
    ledger[114] allocator: op:0:0:4:EasySubScan), isOwning: true, size: 32768, references: 1, life: 277785186463824..0, allocatorManager: [110, life: 277785186414654..0] holds 1 buffers.
        DrillBuf[143], udle: [111 0..32768]
    ledger[112] allocator: op:0:0:4:EasySubScan), isOwning: true, size: 4096, references: 1, life: 277785186046095..0, allocatorManager: [108, life: 277785185921147..0] holds 1 buffers.
        DrillBuf[141], udle: [109 0..4096]
  reservations: 0