Re: [HACKERS] leaks in TopMemoryContext?

2006-01-11 Thread Neil Conway
On Wed, 2006-01-11 at 02:58 -0500, Tom Lane wrote: One comment is that there are worse things than small memory leaks in seldom-followed code paths, especially if those paths are only taken in error cases. While I agree the problem isn't a showstopper, I think it is still worthy of concern:

[HACKERS] Overflow of bgwriter's request queue

2006-01-11 Thread ITAGAKI Takahiro
Hi Hackers, I encountered overflow of bgwriter's file-fsync request queue. It occurred during checkpoints. Each backend would call fsync disorderly in such cases, so that the checkpoint takes a long time and the performance has decreased. It seems to happen frequently on the machines with a lot

[HACKERS] PG process architecture

2006-01-11 Thread Milen Kulev
Hi listers, I am experienced Oracle DBA und now I was given a task to evaluate Postgresql. May first goal is to compare the architecture of Oracle and Postgres. After reading the fine manuals and several mailing lists, I have found that the following parameters are analogous in PG vs Oracle

Re: [HACKERS] leaks in TopMemoryContext?

2006-01-11 Thread Tom Lane
Neil Conway [EMAIL PROTECTED] writes: While I agree the problem isn't a showstopper, I think it is still worthy of concern: the mbutils example was chosen for being clearly broken, not as being the most serious instance of the problem. The issue might occur in *any* situation in which we're

Re: plperl vs LC_COLLATE (was Re: [HACKERS] Possible savepoint bug)

2006-01-11 Thread Andrew Dunstan
The original of this email appears to have disappeared into the ether. cheers andrew Forwarded Message From: Andrew Dunstan [EMAIL PROTECTED] To: Tom Lane [EMAIL PROTECTED] Cc: Greg Stark [EMAIL PROTECTED], Michael Paesold [EMAIL PROTECTED], PostgreSQL Development

Re: [HACKERS] PG process architecture

2006-01-11 Thread Tom Lane
Milen Kulev [EMAIL PROTECTED] writes: My questions is: Where PG is storing data dictionary information (coming form system pg_* tables) while parsing the queries ? There's a limited-size catalog cache in each backend process, which might be the closest analogy to this. Offhand I think it's

Re: [HACKERS] PG process architecture

2006-01-11 Thread Milen Kulev
Hi Harris, from oracle DBA point of view Enterprise DB is VERY cool. My boss will be very happy to hear that there a way to get (paid) support for a PG DB. But at the end I want to undestand how PG (and its clone Enterprise DB ) is working ;) . Hopefully I don't need to read the whole source of

Re: [HACKERS] PG process architecture

2006-01-11 Thread Joshua D. Drake
Milen Kulev wrote: Hi Harris, from oracle DBA point of view Enterprise DB is VERY cool. My boss will be very happy to hear that there a way to get (paid) support for a PG DB. There several highly qualified support vendors for PostgreSQL: SRA America Pervasive and ourselves, the only

[HACKERS] FW: Intermittent Stats Failiures: firefly: HEAD

2006-01-11 Thread Larry Rosenman
Reposting, since it seems to not have made it :( Larry Rosenman wrote: Ever since the stats collector changes, I've seen intermittent failures on 'firefly' in the buildfarm. This is my machine. There is one posted now, and the history has them as well. Could someone look and tell me

Re: [HACKERS] Overflow of bgwriter's request queue

2006-01-11 Thread Tom Lane
ITAGAKI Takahiro [EMAIL PROTECTED] writes: I encountered overflow of bgwriter's file-fsync request queue. It occurred during checkpoints. Each backend would call fsync disorderly in such cases, so that the checkpoint takes a long time and the performance has decreased. It seems to happen

Re: [HACKERS] FW: Intermittent Stats Failiures: firefly: HEAD

2006-01-11 Thread Tom Lane
Larry Rosenman [EMAIL PROTECTED] writes: Ever since the stats collector changes, I've seen intermittent failures on 'firefly' in the buildfarm. Yeah, you're not the only one. We haven't figured out what's causing them. But while fooling with Joachim Wieland's pg_sleep patch just now, I was

[HACKERS] sort operation leads planner to different number of rows?

2006-01-11 Thread Robert Treat
I'm in the process of upgrading one of my servers from 7.3 to 8.1, and have run across a query that is slower on the new 8.1 box. FWIW The data is all freshly loaded and freshly analyzed, and this is 8.1.1 to be precise. The part that I am really curious about right now is this snippit of the

Re: [HACKERS] sort operation leads planner to different number of rows?

2006-01-11 Thread Tom Lane
Robert Treat [EMAIL PROTECTED] writes: Sort (cost=616.64..620.56 rows=1568 width=12) (actual time=46.579..54.641 rows=6407 loops=1) Sort Key: latest_download.host_id -

[HACKERS] Checkpoint question

2006-01-11 Thread Qingqing Zhou
I understand checkpoint code doing something like this: Get RedoRecPtr; Flush all dirty buffers no matter what's its LSN; Write down checkpoint xlog record; So I wonder is it possible flush only dirty buffers with LSN RedoRecPtr to improve checkpoint caused delay?

Re: [HACKERS] Checkpoint question

2006-01-11 Thread Simon Riggs
On Wed, 2006-01-11 at 18:24 -0500, Qingqing Zhou wrote: I understand checkpoint code doing something like this: Get RedoRecPtr; Flush all dirty buffers no matter what's its LSN; Write down checkpoint xlog record; So I wonder is it possible flush only dirty buffers with

Re: [HACKERS] Checkpoint question

2006-01-11 Thread Qingqing Zhou
On Wed, 11 Jan 2006, Simon Riggs wrote: Probably good idea to read Gray Reuter or Vekum Vossen books on transactional systems theory before any such discussion. So can you give me some hints why my thoughts are just wrong? Regards, Qingqing ---(end of

Re: [HACKERS] Checkpoint question

2006-01-11 Thread Tom Lane
Qingqing Zhou [EMAIL PROTECTED] writes: So I wonder is it possible flush only dirty buffers with LSN RedoRecPtr to improve checkpoint caused delay? Certainly not. If LSN RedoRecPtr then you know the buffer contains some changes more recent than the checkpoint, but you cannot tell whether it

Re: [HACKERS] Checkpoint question

2006-01-11 Thread Qingqing Zhou
On Wed, 11 Jan 2006, Tom Lane wrote: Qingqing Zhou [EMAIL PROTECTED] writes: So I wonder is it possible flush only dirty buffers with LSN RedoRecPtr to improve checkpoint caused delay? Certainly not. If LSN RedoRecPtr then you know the buffer contains some changes more recent than

Re: [HACKERS] Checkpoint question

2006-01-11 Thread Qingqing Zhou
On Wed, 11 Jan 2006, Tom Lane wrote: It'd be possible to do something like this: after establishing RedoRecPtr, make one quick pass through the buffers and make a list of what needs to be dumped at that instant. Then go back and do the actual I/O for only those buffers. I'm dubious that