Re: postgres 9.5 DB corruption - Mailing list pgsql-general

On 7/24/19 7:38 AM, Thomas Tignor wrote:
> Hello postgres community,
> 
> Writing again to see if there are insights on this issue. We have had 
> infrequent but recurring corruption since upgrading from postgres 9.1 to 
> postgres 9.5. We are presently on 9.5.16. Our DB-facing app continually 
> performs a mixture of DML, primarily inserts and updates on two specific 
> tables, with no single op being suspect. In the past, corruption events 
> have produced encoding errors on COPY operations (invalid byte sequence 
> for encoding "UTF8"). More recently, they have caused segmentation 
> faults. We were able to take a cold backup after a recent event. 
> SELECTing the corrupted data on our cold backup yields the following 
> stack. Any info on a solution or how to proceed towards a solution would 
> be much appreciated.

More information would be useful:

1) Schema of the tables.

2) Source of the data.


> 
> Thanks in advance.
> 
> 
> (gdb) where
> #0  pglz_decompress (source=source@entry=0xa617904 "0", slen=8139, dest=dest@entry=0x4268e028 "", rawsize=808452096)
atpg_lzcompress.c:745
 
> #1  0x080f3079 in toast_decompress_datum (attr=0xa6178fc) at tuptoaster.c:2210
> #2  0x080f3716 in heap_tuple_untoast_attr (attr=0xa6178fc) at tuptoaster.c:183
> #3  0x08440955 in pg_detoast_datum_packed (datum=<optimized out>) at fmgr.c:2270
> #4  0x084145bf in text_to_cstring (t=0x7592fd2a) at varlena.c:176
> #5  0x0843e874 in FunctionCall1Coll (flinfo=flinfo@entry=0xa614738, collation=collation@entry=0,
arg1=arg1@entry=1972567338)at fmgr.c:1297
 
> #6  0x0843fef8 in OutputFunctionCall (flinfo=0xa614738, val=1972567338) at fmgr.c:1950
> #7  0x080bf84b in printtup (slot=0xa613bf4, self=0xa60d714) at printtup.c:359
> #8  0x08220f9a in ExecutePlan (dest=0xa60d714, direction=<optimized out>, numberTuples=0, sendTuples=<optimized out>,
operation=CMD_SELECT,planstate=0xa613974, estate=0xa6138ec) at execMain.c:1574
 
> #9  standard_ExecutorRun (queryDesc=0xa6134e4, direction=ForwardScanDirection, count=0) at execMain.c:337
> #10 0x08332c1b in PortalRunSelect (portal=portal@entry=0xa6114dc, forward=forward@entry=1 '\001', count=0,
count@entry=2147483647,dest=dest@entry=0xa60d714) at pquery.c:942
 
> #11 0x08333fa7 in PortalRun (portal=portal@entry=0xa6114dc, count=count@entry=2147483647,
isTopLevel=isTopLevel@entry=1'\001', dest=dest@entry=0xa60d714, altdest=altdest@entry=0xa60d714,
completionTag=completionTag@entry=0xffd5d71c"")
 
>      at pquery.c:786
> #12 0x08330ba8 in exec_simple_query (query_string=0xa5f1754 "select * from ams.alert_attribute_bak;") at
postgres.c:1096
> #13 PostgresMain (argc=1, argv=0xa53dbbc, dbname=0xa53daec "ams", username=0xa53dadc "akamai") at postgres.c:4049
> #14 0x080b53af in BackendRun (port=0xa584b78) at postmaster.c:4312
> #15 BackendStartup (port=0xa584b78) at postmaster.c:3986
> #16 ServerLoop () at postmaster.c:1705
> #17 0x082d0dd7 in PostmasterMain (argc=argc@entry=3, argv=argv@entry=0xa53d2a8) at postmaster.c:1313
> #18 0x080b68eb in main (argc=3, argv=0xa53d2a8) at main.c:228
> (gdb)
> 
> 
> 
> Tom    :-)


-- 
Adrian Klaver
adrian.klaver@aklaver.com